Spring MVC | 易学教程

什么是Spring MVC？

SpringMVC是一种Web层MVC框架，该框架简化了传统Java Web开发：传统Java Web开发中一个模块需要定义多个Servlet类，且接收请求中数据时需要调用诸如getParameter方法；而SpringMVC中一个模块只需一个Controller类即可。

1.这里先用最初的方法：

（1）index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
 <a href="./userinfo/toView.do">链接</a>
</body>
</html>

这里点击链接发送请求、

（2）web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>dubhe214</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  
<!--   <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:application.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>DispatcherServlet</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping> -->
  
  <servlet>  
    <servlet-name>ToServlet</servlet-name>
    <servlet-class>com.jd.userinfo.ToServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>ToServlet</servlet-name>
    <url-pattern>/userinfo/toView.do</url-pattern>
  </servlet-mapping>
</web-app>

这时tomcat在列表中找到ToServlet————>因为这个链接是get请求：

（3）ToServlet.java

package com.jd.userinfo;

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

public class ToServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.getRequestDispatcher("../to.jsp").forward(request, response);
	}
}

由get方法去处理这个请求，然后跳转到to.jsp这个页面。

运行成功。

2.这里用Spring来写：

（1）index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
 <a href="./userinfo/toView.do">链接</a>
</body>
</html>

这里发送.do请求

（2）web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>dubhe214</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
   <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:application.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>DispatcherServlet</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping> 
</web-app>

这里捕获.do请求并创建实例化对象。

（3）UserInfoController.java

package com.jd.userinfo;

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

@Controller    //用了标识这个类是控制器  每一个servlet都是一个控制器--->把UserInfoController实例化到IOC容器中
public class UserInfoController {

	@RequestMapping("/userinfo/toView.do")
	public String toView(String id) {   //请求处理Handler
		System.out.println("服务器端"+id);
		return "to";
	}
}

这里在控制器中找到处理.do的方法，并返回to(就是显示页面的名字)值。

但是还需要再次解析。

（4）application.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:mybatis-spring="http://mybatis.org/schema/mybatis-spring"
	xmlns:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://mybatis.org/schema/mybatis-spring http://mybatis.org/schema/mybatis-spring-1.2.xsd
		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-4.3.xsd">
  <!-- 给类创建对象并存储到IOC容器中  @controller @service-->
  <context:component-scan base-package="com.jd"></context:component-scan>
  <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix="/" p:suffix=".jsp">
  </bean>
</beans>

因为刚才的返回值是to，并不是to.jsp。

所以这里解释器拼接成to.jsp。

p:prefix="/"

这个/代表的是WebContent

来源：CSDN

作者：一只奋斗的小强

链接：https://blog.csdn.net/niuxikun/article/details/104306782

标签

servlet

spring框架