SpringMVC
说明下【本文是在网上听课做的笔记，代码是自己敲的，有些文字是复制的老师发的】
SpringMVC概述
使用SpringMVC替换Servlet
Servlet的问题：
1、需要判断调用哪个方法。（逻辑需要自己编写）
2、需要获得request的数据，并且需要手动封装，还要进行类型转换。
3、跳转和转发数据的代码太繁琐。
4、通过ajax请求的对象，需要通过fastjson进行转换，并使用相应对象的输出流写出。
以上问题SpringMVC都给出了解决方案。
1、添加依赖
<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>4.3.18.RELEASE</version> </dependency>
2、在web.xml中配置前端控制器
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd" > <web-app> <display-name>Archetype Created Web Application</display-name> <!-- 前端控制器 --> <servlet> <servlet-name>dispatcherServlet</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:springMVC-Servlet.xml</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>dispatcherServlet</servlet-name> <!-- /表示拦截了除了jsp之外所有的请求 --> <url-pattern>/</url-pattern> </servlet-mapping> </web-app>
3、编写SpringMVC的配置文件（结构和Spring配置文件一致）
<?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 http://www.springframework.org/schema/mvc/spring-mvc.xsd"> <!-- 映射器 --> <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping" /> <!-- 适配器 --> <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/> <!-- 视图解析器 --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/" /> <property name="suffix" value=".jsp"/> </bean> <!-- 配置Controller --> <!-- <bean id="/user" class="com.woniu.controller.UserController"></bean>--> <bean id="/user" class="cn.cqie.controller.UserController"/> </beans>
4、添加Controller
package cn.cqie.controller; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.mvc.Controller; /** * Description： * Author: tiancx * Date: Created in 2021/11/23 21:30 */ public class UserController implements Controller { @Override public ModelAndView handleRequest(javax.servlet.http.HttpServletRequest httpServletRequest, javax.servlet.http.HttpServletResponse httpServletResponse) throws Exception { System.out.println("UserController.handleRequest"); return null; } }
5、通过浏览器访问Controller
SpringMVC的工作机制
DispatcherServlet
<?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 http://www.springframework.org/schema/mvc/spring-mvc.xsd"> <!-- 映射器 BeanNameUrlHandlerMapping 在浏览器中发送/user 通过/user在Spring容器中找到id对应的实例 SimpleUrlHandlerMapping 声明一个映射关系 Properties --> <bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"> <property name="mappings"> <props> <prop key="/user">userController</prop> </props> </property> </bean> <!-- 适配器 SimpleControllerHandlerAdapter 可以执行实现了Controller接口的控制器 HttpRequestHandlerAdapter 可以执行实现了HttpRequestHandler接口的控制器 --> <bean class="org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter" ></bean> <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter" ></bean> <!-- 视图解析器 prefix 从webapp根目录指定 suffix 是后缀 --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/"></property> <property name="suffix" value=".jsp"></property> </bean> <!-- 配置Controller --> <bean id="userController" class="cn.cqie.controller.UserController"></bean> </beans>
Controller的实现
使用注解配置Controller
package cn.cqie.controller; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.servlet.ModelAndView; /** * Description： * Author: tiancx * Date: Created in 2021/11/23 21:30 */ @Controller public class UserController2 { @RequestMapping("userSave") public ModelAndView save(){ System.out.println("UserController2.save"); return new ModelAndView("index"); } }
<?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 http://www.springframework.org/schema/mvc/spring-mvc.xsd"> <context:component-scan base-package="cn.cqie"/> <mvc:annotation-driven></mvc:annotation-driven> <!--这个可以替换掉下面的两个 bean，甚至更多 --> <!-- <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"></bean>--> <!-- <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"></bean>--> <!-- 视图解析器 --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/" /> <property name="suffix" value=".jsp"/> </bean> <!-- 配置Controller --> <!-- <bean id="/user" class="com.woniu.controller.UserController"></bean>--> <bean id="userController" class="cn.cqie.controller.UserController"/> </beans>
ModelAndView类
package cn.cqie.controller; import cn.cqie.pojo.User; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.servlet.ModelAndView; import java.util.ArrayList; import java.util.List; /** * Description： * Author: tiancx * Date: Created in 2021/11/23 21:30 */ @Controller public class UserController2 { // @RequestMapping("testList") 就是在浏览器输入 testList 和以前的servlet一样 @RequestMapping("testList") public ModelAndView list(){ System.out.println("UserController2.save"); List<User> list =new ArrayList<>(); list.add(new User("yx",26)); list.add(new User("wls",20)); list.add(new User("tcx",20)); // /list.jsp ModelAndView ma = new ModelAndView("list"); //request.setAttribute(); ma.addObject("msg","66666"); return ma; } @RequestMapping("testList2") public ModelAndView list2(){ System.out.println("UserController2.save"); List<User> list =new ArrayList<>(); list.add(new User("yx",26)); list.add(new User("wls",20)); list.add(new User("tcx",20)); ModelAndView ma = new ModelAndView("list2"); ma.addObject("msg",list); return ma; } @RequestMapping("testList3") public ModelAndView list3(){ System.out.println("UserController2.save"); List<User> list =new ArrayList<>(); list.add(new User("yx",26)); list.add(new User("wls",20)); list.add(new User("tcx",20)); ModelAndView ma = new ModelAndView("list2"); //request.setAttribute(); 名字默认为类型与泛型的组合 userList ma.addObject(list); return ma; } @RequestMapping("testList4") public String list4(Model model){ System.out.println("UserController2.save"); List<User> list =new ArrayList<>(); list.add(new User("yx",26)); list.add(new User("wls",20)); list.add(new User("tcx",20)); model.addAttribute(list); return "list2"; // /list.jsp } @RequestMapping("testList5") public String list5(Model model){ //重定向 return "redirect:list.jsp"; } }
相关的jsp页面
list.jsp
<%-- Created by IntelliJ IDEA. User: admin Date: 2021/11/24 Time: 21:08 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" isELIgnored="false" language="java" %> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <html> <head> <title>Title</title> </head> <body> ${msg} </body> </html>
list2.jsp
<%-- Created by IntelliJ IDEA. User: admin Date: 2021/11/24 Time: 21:15 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" isELIgnored="false" language="java" %> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <html> <head> <title>Title</title> </head> <body> <ul> <c:forEach items="${userList}" var="user"> <li>${user.name}</li> </c:forEach> </ul> </body> </html>
jstl需要导入的依赖
<!-- https://mvnrepository.com/artifact/javax.servlet/jstl --> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency>
