SpringMVC使用手册

本文最后更新于：2021年1月8日 下午

一、回顾MVC

  1. 用户发请求；
  2. Servlet接收请求数据，并调用响应的业务逻辑方法；
  3. 业务处理完毕后，service层返回更新后的数据给Servlet层；
  4. Servlet转向JSP，由JSP来渲染页面；
  5. 响应给前端更新后的页面

MVC：指Model模型、View视图和Controller控制器的缩写

  • Model：dao、service层等，业务逻辑，保存数据状态
  • View：html、jsp等，显示页面
  • Controller：Servlet等，取得表单数据，调用业务逻辑，转向指定页面

dao层连接数据库；service层调用dao层去执行一些具体的业务；Servlet接收jsp/html等前端的数据，并将数据交给service层处理，之后service层将处理结果返回给servlet层，由servlet控制跳转到哪个界面。

二、回顾Servlet

新建maven工程当父工程，添加pom依赖，之后新建maven module，右键添加框架支持，选择web application 4.0版本，即可获得一个web-app应用module了。

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.2.0.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>jsp-api</artifactId>
        <version>2.2</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>
</dependencies>

  • 编写Servlet类，处理用户请求
package com.gaowl.servlet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

// 该类用于处理用户的请求
public class HelloServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // 1.获取前端参数
        String method = req.getParameter("method");   // 前端的表单中，有一个字段为method，此处我们获取method，并根据其内容做对应的处理
        if (method.equals("add")){
            req.getSession().setAttribute("msg","执行了add方法");
        }
        if (method.equals("delete")){
            req.getSession().setAttribute("msg","执行了delete方法");
        }

        // 2.调用业务层

        // 3.视图转发或者重定向
        req.getRequestDispatcher("/WEB-INF/jsp/hello.jsp").forward(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}
  • 编写前端文件WEB-INF/jsp/hello.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>正在学习Spring和Servlet...2021.1.4</title>
</head>
    
<body>
${msg}
</body>
</html>
  • 在web.xml中注册Servlet
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <!-- 注册对应的Servlet-->
    <servlet>
        <servlet-name>HelloServlet</servlet-name>
        <servlet-class>com.gaowl.servlet.HelloServlet</servlet-class>
    </servlet>
    
    <servlet-mapping>
        <servlet-name>HelloServlet</servlet-name>   <!--和上面名称对应-->
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>

</web-app>
  • 配置tomcat，测试即可
http://localhost:8080/SpringMVC_01_Servlet_war_exploded/hello?method=add

三、SpringMVC介绍

1）优点

  • 轻量级，简单易学
  • 高效 , 基于请求响应的MVC框架
  • 与Spring兼容性好，无缝结合
  • 约定优于配置
  • 功能强大：支持RESTful、数据验证、格式化、拦截器、主题等等

2）执行原理

Spring MVC框架像许多其他MVC框架一样, 以请求为驱动 , 围绕一个中心Servlet分派请求及提供其他功能。

这个中心Servlet指的是DispatcherServlet，它继承自HttpServlet 基类，并将请求分发到不同的处理器。

上图为SpringMVC的一个较完整的流程图，实线表示SpringMVC框架提供的技术，不需要开发者实现，虚线表示需要开发者自己实现。

  1. DispatcherServlet表示前置控制器，是整个SpringMVC的控制中心。用户发出请求，DispatcherServlet接收并拦截请求
  2. HandlerMapping：处理器映射。DispatcherServlet调用HandlerMapping，根据请求url查找Handler。
  3. HandlerExecution：具体的Handler，其根据请求url查找控制器，如上述url中被查找控制器为：hello。
  4. HandlerExecution将解析后的信息传递给DispatcherServlet。
  5. HandlerAdapter处理器适配器，按照特定的规则去执行Handler。
  6. Handler让具体的Controller执行。
  7. Controller将具体的执行信息返回给HandlerAdapter，如ModelAndView。
  8. HandlerAdapter将 视图逻辑名或模型 传递给DispatcherServlet。
  9. DispatcherServlet调用视图解析器(ViewResolver)来解析HandlerAdapter传递的逻辑视图名。
  10. ViewResolver视图解析器，将解析的逻辑视图名传给DispatcherServlet。
  11. DispatcherServlet根据视图解析器解析的视图结果，调用具体的视图。
  12. 将最终视图呈现给用户。

四、使用注解开发

1）初始化

导入pom依赖，创建lib文件夹并导入相关库，通过build防止资源过滤

<build>
   <resources>
       <resource>
           <directory>src/main/java</directory>
           <includes>
               <include>**/*.properties</include>
               <include>**/*.xml</include>
           </includes>
           <filtering>false</filtering>
       </resource>
       <resource>
           <directory>src/main/resources</directory>
           <includes>
               <include>**/*.properties</include>
               <include>**/*.xml</include>
           </includes>
           <filtering>false</filtering>
       </resource>
   </resources>
</build>

2）配置 web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    
    <servlet>
        <!-- 1.注册DispatcherServlet -->
        <servlet-name>SpringMVC</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!-- 2.通过初始化参数关联 SpringMVC配置文件 -->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <!-- 3.设定启动顺序，数字越小，启动越早 -->
        <load-on-startup>1</load-on-startup>
    </servlet>

   
    <servlet-mapping>
        <servlet-name>SpringMVC</servlet-name>
        <url-pattern>/</url-pattern>     <!--所有请求都会被springmvc拦截 -->
    </servlet-mapping>

</web-app>
  • <url-pattern>/</url-pattern>：匹配所有的请求；（不包括.jsp，即.jsp 不会进入spring的 DispatcherServlet类）
  • <url-pattern>/*</url-pattern> ：匹配所有的请求；（包括.jsp）

3）编写SpringMVC配置文件

springmvc-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       https://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc
       https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!-- 1.自动扫描包，让指定包下的注解生效,由IOC容器统一管理 -->
    <!-- 2.让Spring MVC不处理静态资源(.css .js .html  .mp4等) -->
    <!-- 3.通过mvc注解驱动自动配置DefaultAnnotationHandlerMapping 和AnnotationMethodHandlerAdapter实例 -->
    <context:component-scan base-package="com.gaowl.controller"/>
    <mvc:default-servlet-handler />
    <mvc:annotation-driven />


    <!--使用SpringMVC必须配置 处理器映射器、处理器适配器和视图解析器，
        前两者通过 开启注解驱动 后自动配置，因此，只需要配置视图解析器即可-->

    <!-- 视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
          id="internalResourceViewResolver">
        <!-- 前缀和后缀 -->
        <property name="prefix" value="/WEB-INF/jsp/" />
        <property name="suffix" value=".jsp" />
    </bean>

</beans>

4）创建控制器类

package com.gaowl.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("/HelloController")
public class HelloController {

    //真实访问地址 : 项目名/HelloController/hello
    @RequestMapping("/hello")
    public String sayHello(Model model){

        model.addAttribute("msg","hello,this is SpringMVC");  // 封装数据
        return "hello";   // 视图名，其会被视图解析器拼接为web-inf/jsp/hello.jsp
    }
    
    @RequestMapping("tv")
    public String testView(Model model){
        model.addAttribute("msg","测试多个路径指向同一个视图");
        return "hello";
    }

}
  • @Controller注解可以使Spring IOC容器初始化时自动扫描到该控制器类

  • @RequestMapping注解为映射请求路径，这里类与方法上都有映射注解，所以访问路径应该是/HelloController/hello；

  • 方法中声明Model类型的参数是为了把Action中的数据带到视图中；

  • 方法返回的结果是视图名hello，加上配置文件中的前后缀变成WEB-INF/jsp/hello.jsp。

5）创建视图并测试

在WEB-INF/ jsp目录下创建hello.jsp 视图文件， 其可以直接取出并展示从Controller带回的信息；

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
${msg}
</body>
</html>

五、RESTFul风格

采用传统方法操作资源时，url一般为http://127.0.0.1/item/queryItem.action?id=1这种；

RestFul风格隐藏了变量名称，如http://127.0.0.1/item/1，同一个请求地址可以实现不同的功能

  • 在@RequestMapping中通过{}指定变量，之后再通过@PathVariable获取到具体的数据；
  • 当地址栏请求提供的数据 和 限定数据类型不一致时，会报400错误。
  • 此外，可以通过method属性指定请求的类型，如GET、POST、DELETE等。
    • @RequestMapping(value = "/hello",method = {RequestMethod.GET})
    • 所有的地址栏请求 默认为HTTP GET 类型
  • 方法级别的注解，除了RequestMapping外，还有@GetMapping、@PostMapping、@PutMapping、@DeleteMapping、@PatchMapping等，其中GetMapping用的比较多，其等价于@RequestMapping(value = "/hello",method = {RequestMethod.GET})
package com.gaowl.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class RestFulController {
    //映射访问路径
    @RequestMapping("/commit/{p1}/{p2}")
    public String index(@PathVariable int p1, @PathVariable int p2, Model model){

        int result = p1+p2;
        //Spring MVC会自动实例化一个Model对象用于向视图中传值
        model.addAttribute("msg", "结果："+result);
        //返回视图位置
        return "hello";

    }
}

六、结果跳转和数据处理

1）结果转发和重定向

  • ModelAndVIew：最终跳转的视图页面为{视图解析器中前缀} + viewName +{视图解析器中后缀}
<!-- 视图解析器 -->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
     id="internalResourceViewResolver">
   <!-- 前缀、后缀 -->
   <property name="prefix" value="/WEB-INF/jsp/" />
   <property name="suffix" value=".jsp" />
</bean>
public class ControllerTest1 implements Controller {
   public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
       
       //返回一个模型视图对象
       ModelAndView mv = new ModelAndView();
       mv.addObject("msg","ControllerTest1");
       mv.setViewName("test");
       
       return mv;
  }
}
  • ServletAPI：其可以不需要视图解析器
@Controller
public class ResultGo {
   // 输出信息
   @RequestMapping("/result/t1")
   public void test1(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
       rsp.getWriter().println("Hello,Spring BY servlet API");
  }
    
  // 转发  
  @RequestMapping("/result/t2")
   public void test3(HttpServletRequest req, HttpServletResponse rsp) throws Exception {
       req.setAttribute("msg","测试转发请求/result/t2");
       req.getRequestDispatcher("/WEB-INF/jsp/test.jsp").forward(req,rsp);
  }
   // 重定向
   @RequestMapping("/result/t3")
   public void test2(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
       rsp.sendRedirect("/index.jsp");
  }



}
  • SpringMVC：重定向无需视图解析器；转发时，若无视图解析器，需保证文件可以访问到
// 有视图解析器
@Controller
public class ResultSpringMVC2 {
   @RequestMapping("/rsm2/t1")
   public String test1(){
       //转发
       return "test";
  }

   @RequestMapping("/rsm2/t2")
   public String test2(){
       //重定向
       return "redirect:/index.jsp";
       //return "redirect:hello.do"; //hello.do为另一个请求/
  }

}
// 无视图解析器的控制器类实现
@Controller
public class ResultSpringMVC {
   @RequestMapping("/rsm/t1")
   public String test1(){
       //转发
       return "/index.jsp";
  }

   @RequestMapping("/rsm/t2")
   public String test2(){
       //转发二
       return "forward:/index.jsp";
  }

   @RequestMapping("/rsm/t3")
   public String test3(){
       //重定向
       return "redirect:/index.jsp";
  }
}

2）处理提交数据

  • 当提交的域名称和处理方法的参数名不一致时，手动指定参数名@RequestParam("username")
@RequestMapping("/hello")
public String hello(@RequestParam("username") String name){
   System.out.println(name);
   return "hello";
}
  • 当提交的数据是一个对象时，接收方法的参数直接也设置成对象即可。
    • 前端传递的参数名和对象名必须一致，否则会为null
@RequestMapping("/user")
public String user(User user){
   System.out.println(user);
   return "hello";
}

3）数据显示到前端

  • ModelAndView
public class ControllerTest1 implements Controller {
 public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception {
     //返回一个模型视图对象
     ModelAndView mv = new ModelAndView();
     mv.addObject("msg","ControllerTest1");
     mv.setViewName("test");

     return mv;
}
}
  • ModelMap：继承了 LinkedMap ，除了实现了自身的一些方法外，同时还有 LinkedMap 的方法和特性；
@RequestMapping("/hello")
public String hello(@RequestParam("username") String name, ModelMap model){

 model.addAttribute("name",name);   //相当于req.setAttribute("name",name);   
 return "hello";
}
  • Model：方法较少，但简单好用啊！
@RequestMapping("/ct2/hello")
public String hello(@RequestParam("username") String name, Model model){

 model.addAttribute("msg",name);    
 return "test";
}

4）中文乱码问题

  • 在首页 提交表单，
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>
  $END$
  <form action="e/t" method="post">
    <input type="text" name="name">
    <input type="submit">
  </form>
  </body>
</html>
  • 编写其控制器类
package com.gaowl.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class EncodingController {
    @RequestMapping("/e/t")
    public String test(Model model, String name){
        model.addAttribute("msg",name);
        return "hello";
    }
}
  • 此时，测试提交请求会出现中文乱码问题。解决方案非常简单，在web.xml中导入Spring自带的拦截器即可
<filter>
    <filter-name>encoding</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
        <param-name>encoding</param-name>
        <param-value>utf-8</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>encoding</filter-name>
    <url-pattern>/*</url-pattern>   <!-- 带*会拦截JSP文件然后对其进行相应的处理，不带的话就不会拦截-->
</filter-mapping>
  • 若还是乱码（比如get请求等），可尝试下述代码（没试过，占个坑，但愿这辈子都用不到）
package com.kuang.filter;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Map;

/**
* 解决get和post请求 全部乱码的过滤器
*/
public class GenericEncodingFilter implements Filter {

   @Override
   public void destroy() {
  }

   @Override
   public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
       //处理response的字符编码
       HttpServletResponse myResponse=(HttpServletResponse) response;
       myResponse.setContentType("text/html;charset=UTF-8");

       // 转型为与协议相关对象
       HttpServletRequest httpServletRequest = (HttpServletRequest) request;
       // 对request包装增强
       HttpServletRequest myrequest = new MyRequest(httpServletRequest);
       chain.doFilter(myrequest, response);
  }

   @Override
   public void init(FilterConfig filterConfig) throws ServletException {
  }

}

//自定义request对象，HttpServletRequest的包装类
class MyRequest extends HttpServletRequestWrapper {

   private HttpServletRequest request;
   //是否编码的标记
   private boolean hasEncode;
   //定义一个可以传入HttpServletRequest对象的构造函数，以便对其进行装饰
   public MyRequest(HttpServletRequest request) {
       super(request);// super必须写
       this.request = request;
  }

   // 对需要增强方法 进行覆盖
   @Override
   public Map getParameterMap() {
       // 先获得请求方式
       String method = request.getMethod();
       if (method.equalsIgnoreCase("post")) {
           // post请求
           try {
               // 处理post乱码
               request.setCharacterEncoding("utf-8");
               return request.getParameterMap();
          } catch (UnsupportedEncodingException e) {
               e.printStackTrace();
          }
      } else if (method.equalsIgnoreCase("get")) {
           // get请求
           Map<String, String[]> parameterMap = request.getParameterMap();
           if (!hasEncode) { // 确保get手动编码逻辑只运行一次
               for (String parameterName : parameterMap.keySet()) {
                   String[] values = parameterMap.get(parameterName);
                   if (values != null) {
                       for (int i = 0; i < values.length; i++) {
                           try {
                               // 处理get乱码
                               values[i] = new String(values[i]
                                      .getBytes("ISO-8859-1"), "utf-8");
                          } catch (UnsupportedEncodingException e) {
                               e.printStackTrace();
                          }
                      }
                  }
              }
               hasEncode = true;
          }
           return parameterMap;
      }
       return super.getParameterMap();
  }

   //取一个值
   @Override
   public String getParameter(String name) {
       Map<String, String[]> parameterMap = getParameterMap();
       String[] values = parameterMap.get(name);
       if (values == null) {
           return null;
      }
       return values[0]; // 取回参数的第一个值
  }

   //取所有值
   @Override
   public String[] getParameterValues(String name) {
       Map<String, String[]> parameterMap = getParameterMap();
       String[] values = parameterMap.get(name);
       return values;
  }
}

七、JSON交互处理

后端：提供接口和数据

前端：独立部署，对前端数据进行渲染

JSON 是 JavaScript 对象的字符串表示法，它使用文本表示一个 JS 对象的信息，本质是一个字符串。

// javaScript对象
var obj = {a: 'Hello', b: 'World'}; //这是一个对象，注意键名也是可以使用引号包裹的

// json字符串
var json = '{"a": "Hello", "b": "World"}';

1）JSON字符串和对象转换

<script type="text/javascript">
    //编写一个js的对象
    var user = {
        name:"秦疆",
        age:3,
        sex:"男"
    };

    //将js对象转换成json字符串
    var str = JSON.stringify(user);
    console.log(str);

    //将json字符串转换为js对象
    var user2 = JSON.parse(str);
    console.log(user2.age,user2.name,user2.sex);
</script>

2）代码测试

  • 导入库文件
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>SpringMvc_Kuang</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>SpringMVC-05-json</artifactId>

    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>

    <dependencies>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.8</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.16</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.60</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
    </dependencies>

</project>
  • 配置web.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <!--1.注册servlet-->
    <servlet>
        <servlet-name>SpringMVC</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--通过初始化参数指定SpringMVC配置文件的位置，进行关联-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-servlet.xml</param-value>
        </init-param>
        <!-- 启动顺序，数字越小，启动越早 -->
        <load-on-startup>1</load-on-startup>
    </servlet>

    <!--所有请求都会被springmvc拦截 -->
    <servlet-mapping>
        <servlet-name>SpringMVC</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <filter>
        <filter-name>encoding</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

</web-app>
  • 配置Spring的核心配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       https://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc
       https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!-- 自动扫描指定的包，下面所有注解类交给IOC容器管理 -->
    <context:component-scan base-package="com.gaowl.controller"/>

    <!-- 统一解决json中文乱码问题 -->
    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8"/>
            </bean>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                <property name="objectMapper">
                    <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                        <property name="failOnEmptyBeans" value="false"/>
                    </bean>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

    <!-- 视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
          id="internalResourceViewResolver">
        <!-- 前缀 -->
        <property name="prefix" value="/WEB-INF/jsp/" />
        <!-- 后缀 -->
        <property name="suffix" value=".jsp" />
    </bean>

</beans>
  • 编写实体类User
package com.gaowl.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
    private String name;
    private int age;
    private String sex;
}
  • 编写Controller
    • 若有Controller注释，且web.xml中配置了视图解析器，当访问RequestMappering所对应的地址时，所调用的方法返回视图名，跳转到相应的视图
    • 若想不跳转视图，仅返回字符串，可以在方法上加@ResponseBody注解，或者在类上面通过@RestController替换掉原先的@Controller
    • jackson库：
      • 将java对象转换为字符串：new ObjectMapper().writeValueAsString(user)
    • FastJSON库：
      • java对象 和 JSON字符串 互转：JSON.toJSONString(user1)、JSON.parseObject(s2, User.class)
      • Java对象 和 JSON对象 互转：(JSONObject) JSON.toJSON(user1)、JSON.toJavaObject(jsonObject, User.class)
package com.gaowl.controller;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.gaowl.pojo.User;
import org.junit.Test;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import java.lang.reflect.Array;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;


@RestController
// @Controller
public class UserController {

    // 通过指定produces属性解决中文乱码问题
    // @RequestMapping(value = "/json1",produces = "application/json;charset=utf-8")

    @RequestMapping("/j1")
    // @ResponseBody
    public String json1() throws JsonProcessingException {
        //创建一个jackson的对象映射器，用来解析数据
        ObjectMapper mapper = new ObjectMapper();

        User user = new User("阿龙1号", 23, "男");
        String str = mapper.writeValueAsString(user);   // 通过jackson库将 User对象 解析为 json字符串

        //由于@ResponseBody注解，不再返回视图，这里会将str转成json格式返回；十分方便
        return str;
    }


    @RequestMapping("/j2")
    public String json2() throws JsonProcessingException {
        ObjectMapper mapper = new ObjectMapper();

        User user1 = new User("阿龙1号", 23, "男");
        User user2 = new User("阿龙2号", 23, "男");
        User user3 = new User("阿龙3号", 23, "男");
        User user4 = new User("阿龙4号", 23, "男");
        ArrayList<User> list = new ArrayList<>();
        list.add(user1);
        list.add(user2);
        list.add(user3);
        list.add(user4);

        String str = mapper.writeValueAsString(list);
        return str;
    }


    @RequestMapping("/j3")
    public String json3() throws JsonProcessingException {

        ObjectMapper mapper = new ObjectMapper();

        Date date = new Date();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

        String str = mapper.writeValueAsString(sdf.format(date));
        return str;
    }


    @Test
    public void FastJsonDemo(){
        User user1 = new User("1号", 3, "男");
        User user2 = new User("2号", 3, "男");
        User user3 = new User("3号", 3, "男");
        User user4 = new User("4号", 3, "男");
        ArrayList<User> list = new ArrayList<>();
        list.add(user1);
        list.add(user2);
        list.add(user3);
        list.add(user4);
        System.out.println(list+"\n");

        // java对象 转 JSON字符串
        String s1 = JSON.toJSONString(list);
        String s2 = JSON.toJSONString(user1);
        System.out.println(s1+"\n"+s2+"\n");

        // JSON字符串 转 Java对象
        ArrayList<User> array_parse = JSON.parseObject(s1, ArrayList.class);
        User user_parse = JSON.parseObject(s2, User.class);
        System.out.println(array_parse); // TODO列表内部不是User类型的数据....
        System.out.println(user_parse+"\n");


        // Java对象 转 JSON对象
        JSONObject jsonObject = (JSONObject) JSON.toJSON(user1);
        System.out.println(jsonObject+"\n");


        // JSON对象 转 Java对象
        User user = JSON.toJavaObject(jsonObject, User.class);
        System.out.println(user);
    }
}

八、整合SSM框架（！！！重点掌握）

1）构建MySQL数据库

CREATE DATABASE `ssmbuild`;

USE `ssmbuild`;

DROP TABLE IF EXISTS `books`;

CREATE TABLE `books` (
`bookID` INT(10) NOT NULL AUTO_INCREMENT COMMENT '书id',
`bookName` VARCHAR(100) NOT NULL COMMENT '书名',
`bookCounts` INT(11) NOT NULL COMMENT '数量',
`detail` VARCHAR(200) NOT NULL COMMENT '描述',
KEY `bookID` (`bookID`)
) ENGINE=INNODB DEFAULT CHARSET=utf8;

INSERT  INTO `books`(`bookID`,`bookName`,`bookCounts`,`detail`)VALUES 
(1,'Java',1,'从入门到放弃'),
(2,'MySQL',10,'从删库到跑路'),
(3,'Linux',5,'从进门到进牢');

2）基本环境配置

  • 新建maven空项目，添加web支持，导入相关pom依赖，并配置静态资源过滤，添加lib文件夹
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>ssmbuild_kuang</artifactId>
    <version>1.0-SNAPSHOT</version>

    <!-- 安装依赖项：Junit、mysql数据库驱动、连接池、servlet、jsp、mybatis、spring等等 -->
    <dependencies>
        <!--Junit-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <!--数据库驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <!-- 数据库连接池 -->
        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.5.2</version>
        </dependency>

        <!-- Servlet - JSP -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <!--Mybatis-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.6</version>
        </dependency>

        <!--Spring-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.16</version>
        </dependency>
    </dependencies>

    <!-- 静态资源导出 -->
    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>

</project>

  • 建立基本结构和框架

    • com.gaowl.pojo

    • com.gaowl.dao

    • com.gaowl.service

    • com.gaowl.controller

    • mybatis.xml

      <?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
       PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
       "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

</configuration>

    • applicationContext.xml

      <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd">

</beans>

3）编写Mybatis底层文件

  • 编写MysqL数据库配置database.properties

    jdbc.driver=com.mysql.jdbc.Driver
# 如果MySQL版本为8.0+，需要还需要通过serverTimezone=UTC设置时区
jdbc.url=jdbc:mysql://localhost:3306/ssmbuild?useSSL=false&useUnicode=true&characterEncoding=utf8
jdbc.username=root
jdbc.password=root

  • 编写mybatis核心配置文件mybatis-config.xml

    <?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <typeAliases>
        <package name="com.gaowl.pojo"/>
    </typeAliases>
    <mappers>
<!--        <mapper resource="com/gaowl/dao/BookMapper.xml"/>-->
        <mapper class="com.gaowl.dao.BookMapper"/>
    </mappers>

</configuration>

  • 编写数据库对应的实体类Book、其Dao层的Mapper接口、接口实现Mapper.xml

    package com.gaowl.pojo;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Books {
    private int bookID;
    private String bookName;
    private int bookCounts;
    private String detail;
}
    package com.gaowl.dao;
import com.gaowl.pojo.Books;
import org.apache.ibatis.annotations.Param;
import java.util.List;

public interface BookMapper {
    // 增加一本Book
    int addBook(Books book);

    // 根据id删除一本Book
    int deleteBookById(@Param("bookID") int id);

    // 更新Book
    int updateBook(Books books);

    // 根据id查询,返回一本Book
    Books queryBookById(@Param("bookID") int id);

    // 查询全部Book,返回list集合
    List<Books> queryAllBook();
}
    <?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.gaowl.dao.BookMapper">

    <!--增加一个Book-->
    <insert id="addBook" parameterType="Books">
        insert into ssmbuild.books(bookName,bookCounts,detail)
        values (#{bookName}, #{bookCounts}, #{detail})
    </insert>

    <!--根据id删除一个Book-->
    <delete id="deleteBookById" parameterType="int">
        delete from ssmbuild.books where bookID=#{bookID}
    </delete>

    <!--更新Book-->
    <update id="updateBook" parameterType="Books">
        update ssmbuild.books
        set bookName = #{bookName},bookCounts = #{bookCounts},detail = #{detail}
        where bookID = #{bookID}
    </update>

    <!--根据id查询,返回一个Book-->
    <select id="queryBookById" resultType="Books">
        select * from ssmbuild.books
        where bookID = #{bookID}
    </select>

    <!--查询全部Book-->
    <select id="queryAllBook" resultType="Books">
        SELECT * from ssmbuild.books
    </select>

</mapper>

  • 编写service层的接口和实现类，其调用dao层

    package com.gaowl.service;

import com.gaowl.pojo.Books;
import java.util.List;

//BookService：接口中的方法和dao中方法名一致，因此，其可以通过调用dao层的方法实现这些业务
public interface BookService {
    //增加一个Book
    int addBook(Books book);

    //根据id删除一个Book
    int deleteBookById(int id);

    //更新Book
    int updateBook(Books books);

    //根据id查询,返回一个Book
    Books queryBookById(int id);

    //查询全部Book,返回list集合
    List<Books> queryAllBook();
}
    package com.gaowl.service;

import com.gaowl.dao.BookMapper;
import com.gaowl.pojo.Books;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

//@Service
public class BookServiceImpl implements BookService {

    // service层调用dao层：通过set方法指定具体的业务，便于spring管理

    private BookMapper bookMapper;
    //@Autowired
    public void setBookMapper(BookMapper bookMapper) {
        this.bookMapper = bookMapper;
    }

    @Override
    public int addBook(Books book) {
        return bookMapper.addBook(book);
    }

    @Override
    public int deleteBookById(int id) {
        return bookMapper.deleteBookById(id);
    }

    @Override
    public int updateBook(Books books) {
        return bookMapper.updateBook(books);
    }

    @Override
    public Books queryBookById(int id) {
        return bookMapper.queryBookById(id);
    }

    @Override
    public List<Books> queryAllBook() {
        return bookMapper.queryAllBook();
    }
}

    至此，底层所有操作编写完成

4）Spring层

  • 通过配置文件spring-dao.xml整合Mybatis：

    <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       https://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 1.关联数据库文件，mysql和jdbc的一些配置信息 -->
    <context:property-placeholder location="classpath:database.properties"/>

    <!-- 2.数据库连接池 -->
    <!--数据库连接池
        dbcp 半自动化操作 不能自动连接
        c3p0 自动化操作（自动的加载配置文件 并且设置到对象里面）
    -->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!-- 配置连接池属性 -->
        <property name="driverClass" value="${jdbc.driver}"/>
        <property name="jdbcUrl" value="${jdbc.url}"/>
        <property name="user" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>

        <!-- c3p0连接池大小、关闭自动提交、连接超时时间、失败重试次数 -->
        <property name="maxPoolSize" value="30"/>
        <property name="minPoolSize" value="10"/>
        <property name="autoCommitOnClose" value="false"/>
        <property name="checkoutTimeout" value="10000"/>
        <property name="acquireRetryAttempts" value="2"/>
    </bean>

    <!-- 3.配置SqlSessionFactory对象：注入连接池、关联mybatis配置文件 -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
    </bean>

    <!-- 4.配置动态扫描，自动将Dao接口注入到spring容器中 -->
    <!--解释 ：https://www.cnblogs.com/jpfss/p/7799806.html-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!-- 注入sqlSessionFactory -->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <!-- 给出需要扫描Dao接口包 -->
        <property name="basePackage" value="com.gaowl.dao"/>
    </bean>

</beans>

  • 通过配置文件spring-service.xml整合service层：

    <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans.xsd
   http://www.springframework.org/schema/context
   http://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 1.扫描service相关的bean -->
    <context:component-scan base-package="com.gaowl.service" />

    <!-- 2.将业务类BookServiceImpl注入到IOC容器中。此处为配置实现，也可以通过@Service注解实现 -->
    <bean id="BookServiceImpl" class="com.gaowl.service.BookServiceImpl">
        <property name="bookMapper" ref="bookMapper"/>
    </bean>

    <!-- 3.配置事务管理器 -->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <!-- 注入数据库连接池 -->
        <property name="dataSource" ref="dataSource" />
    </bean>

</beans>

5）springMVC层

  • 配置web.xml：

    <?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <!-- 1.注册DispatcherServlet -->
    <servlet>
        <servlet-name>DispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <!-- 一定要注意:我们这里加载的是总的配置文件，之前被这里坑了！-->
            <param-value>classpath:applicationContext.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>DispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>


    <!-- 2.开启中文乱码过滤encodingFilter -->
    <filter>
        <filter-name>encodingFilter</filter-name>
        <filter-class>
            org.springframework.web.filter.CharacterEncodingFilter
        </filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>utf-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>encodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <!-- 3.设置Session过期时间 -->
    <session-config>
        <session-timeout>15</session-timeout>
    </session-config>

</web-app>

  • 配置spring-mvc.xml：

    <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans.xsd
   http://www.springframework.org/schema/context
   http://www.springframework.org/schema/context/spring-context.xsd
   http://www.springframework.org/schema/mvc
   https://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!-- 1.开启SpringMVC注解驱动、静态资源过滤 -->
    <mvc:annotation-driven />
    <mvc:default-servlet-handler/>

    <!-- 2.扫描web相关的bean -->
    <context:component-scan base-package="com.gaowl.controller" />

    <!-- 3.配置ViewResolver视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
        <property name="prefix" value="/WEB-INF/jsp/" />
        <property name="suffix" value=".jsp" />
    </bean>

</beans>

  • 通过applicationContext.xml整合dao、service、controller层的spring配置文件

    <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd">

    <import resource="spring-dao.xml"/>
    <import resource="spring-service.xml"/>
    <import resource="spring-mvc.xml"/>

</beans>

  • 编写controller及视图层

    • 首页index.jsp

      <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE HTML>
<html>
<head>
  <title>首页</title>
  <style type="text/css">
    a {
      text-decoration: none;
      color: black;
      font-size: 18px;
    }
    h3 {
      width: 180px;
      height: 38px;
      margin: 100px auto;
      text-align: center;
      line-height: 38px;
      background: deepskyblue;
      border-radius: 4px;
    }
  </style>
</head>
<body>

<h3>
  <a href="${pageContext.request.contextPath}/book/allBook">点击进入列表页</a>
</h3>
</body>
</html>

    • 查询所有书籍

      控制类方法：调用service中的查询方法，并通过model将结果传递给对应的allBook.jsp文件

      @RequestMapping("/allBook")
public String list(Model model) {
    List<Books> list = bookService.queryAllBook();
    model.addAttribute("bookList", list);   // 该boolList可以在jsp文件中，通过EL表达式拿到
    return "allBook";
}
      <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>书籍列表</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- 引入 Bootstrap -->
    <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>

<div class="container">

    <div class="row clearfix">
        <div class="col-md-12 column">
            <div class="page-header">
                <h1>
                    <small>书籍列表 —— 显示所有书籍</small>
                </h1>
            </div>
        </div>
    </div>

    <div class="row">
        <div class="col-md-4 column">
            <a class="btn btn-primary" href="${pageContext.request.contextPath}/book/toAddBook">新增</a>
        </div>
    </div>

    <div class="row clearfix">
        <div class="col-md-12 column">
            <table class="table table-hover table-striped">
                <thead>
                <tr>
                    <th>书籍编号</th>
                    <th>书籍名字</th>
                    <th>书籍数量</th>
                    <th>书籍详情</th>
                    <th>操作</th>
                </tr>
                </thead>

                <tbody>
                <c:forEach var="book" items="${requestScope.get('bookList')}">
                    <tr>
                        <td>${book.getBookID()}</td>
                        <td>${book.getBookName()}</td>
                        <td>${book.getBookCounts()}</td>
                        <td>${book.getDetail()}</td>
                        <td>
                            <a href="${pageContext.request.contextPath}/book/toUpdateBook?id=${book.getBookID()}">更改</a> |
                            <a href="${pageContext.request.contextPath}/book/del/${book.getBookID()}">删除</a>
                        </td>
                    </tr>
                </c:forEach>
                </tbody>
            </table>
        </div>
    </div>
</div>

</body>
</html>

    • 添加一本新书

      控制器类的方法：index中的按钮绑定的是toAddBook方法，跳转到添加书籍的界面addBook.jsp,而其提交时绑定的action为addBook方法，此方法中调用service层中的方法进行书籍的添加，最后重定向到所有图书的界面，显示所有书籍。

      @RequestMapping("/toAddBook")
public String toAddBook(Books books){
    return "addBook";
}
@RequestMapping("/AddBook")
public String addBook(Books books){
    System.out.println(books);
    bookService.addBook(books);
    return "redirect:/book/allBook";
}
      <%--
  Created by IntelliJ IDEA.
  User: GWL
  Date: 2021/1/7
  Time: 10:16
  To change this template use File | Settings | File Templates.
--%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<html>
<head>
    <title>新增书籍</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- 引入 Bootstrap -->
    <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
<div class="container">

    <div class="row clearfix">
        <div class="col-md-12 column">
            <div class="page-header">
                <h1>
                    <small>新增书籍</small>
                </h1>
            </div>
        </div>
    </div>
    <form action="${pageContext.request.contextPath}/book/AddBook" method="post">
        书籍名称：<input type="text" name="bookName"><br><br><br>
        书籍数量：<input type="text" name="bookCounts"><br><br><br>
        书籍详情：<input type="text" name="detail"><br><br><br>
        <input type="submit" value="添加">
    </form>

</div>

</body>
</html>

    • 更新书籍信息

      控制器中的方法：拿到index.jsp传递过来的id时，先调用service的方法拿到对应id的书籍信息，然后将这个信息传递给updateBook.jsp，在这个视图进行书籍信息的修改；当修改完提交时，该jsp的action属性绑定的方法UpdateBook触发，再次调用service层的方法，将更新到的书籍信息持久化到MySQL数据库中；最后返回所有书籍信息的显示界面

      @RequestMapping("/toUpdateBook")
public String toUpdateBook(Model model, int id){
    System.out.println(id);
    Books books = bookService.queryBookById(id);
    System.out.println(books);
    model.addAttribute("book",books);  // 将信息传递给updateBook.jsp
    return "updateBook";
}
@RequestMapping("/UpdateBook")
public String UpdateBook(Model model, Books book){
    bookService.updateBook(book);
    return "redirect:/book/allBook";
}
      <%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>修改信息</title>
</head>
<body>
<div class="container">
    <div class="row clearfix">
        <div class="col-md-12 column">
            <div class="page-header">
                <h1>
                    <small>修改信息</small>
                </h1>
            </div>
        </div>
    </div>
    <form action="${pageContext.request.contextPath}/book/UpdateBook">
        <input  name="bookID" value="${book.getBookID()}"/>
        书籍名称：<input type="text" name="bookName" value="${book.getBookName()}"/>
        书籍数量：<input type="text" name="bookCounts" value="${book.getBookCounts()}"/>
        书籍详情：<input type="text" name="detail" value="${book.getDetail() }"/>
        <input type="submit" value="提交"/>
    </form>
</div>

</body>
</html>

    • 删除一本书

      直接调用service层的方法，其中id在index.jsp中通过restful风格传递，因此此处需要在@RequestMappering中获取

      @RequestMapping("del/{bookID}")
public String delBook(Model model, @PathVariable("bookID") int id){
    bookService.deleteBookById(id);
    return "redirect:/book/allBook";
}

    • 查询一本书

6）最终界面展示

九、Ajax

十、拦截器和文件传输

占坑，看了一点感觉没多大意思，SpringBoot去了

SSM框架
SpringMVC

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