SpringMVC源码(一)：源码运行环境搭建

一、创建smvc子模块

　　子模块选择gradle

二、实体类代码

2.1、User实体

public class User {

   private String name;

   public User() {
   }

   public User(String name) {
      this.name = name;
   }

   public String getName() {
      return name;
   }

   public void setName(String name) {
      this.name = name;
   }

}

2.2、Controller控制器

import com.snails.bean.User;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import java.util.ArrayList;
import java.util.List;

@Controller
public class HelloController {

   @RequestMapping("/userlist")
   public String hello(Model model){
      System.out.println("snials");
      List<User> userList = new ArrayList<>();
      User user1 = new User("张三");
      User user2 = new User("李四");
      userList.add(user1);
      userList.add(user2);
      model.addAttribute("users",userList);
      return "userlist";
   }
}

三、配置文件

3.1、添加Spring配置文件spring-config.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">

    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/" />
        <property name="suffix" value=".jsp" />
    </bean>
    <bean id = "user" class="com.snails.bean.User"></bean>
</beans>

3.2、添加SpringMVC配置文件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"
       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">

    <context:component-scan base-package="com.snails"></context:component-scan>
    <mvc:default-servlet-handler/>
    <mvc:annotation-driven></mvc:annotation-driven>
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="suffix" value=".jsp"></property>
        <property name="prefix" value="/WEB-INF/jsp/"></property>
    </bean>
</beans>

 

3.3、添加web.xml文件

 

　　新增webapp文件夹，在webapp文件夹下新建WEB-INF,在WEB-INF文件夹添加web.xml文件，wweb.xml文件详情如下:

<?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">
    <!--Spring配置文件-->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:spring-config.xml</param-value>
    </context-param>

    <servlet>
        <servlet-name>mvc-test</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--SpringMVC配置文件-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:applicationContext.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
        <async-supported>true</async-supported>
    </servlet>

    <servlet-mapping>
        <servlet-name>mvc-test</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
</web-app>

四、项目依赖

　　build.gradle详情如下

plugins {
    id 'java'
    id 'war'
}

group 'org.springframework'
version '5.2.9.BUILD-SNAPSHOT'

sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    compile(project(":spring-context"))
    compile(project(":spring-context-support")) // freemarker需要，不加可能报错
    compile(project(":spring-webmvc"))
    compile(project(":spring-beans"))
    compile(project(":spring-core"))
    compile(project(":spring-jdbc"))
    compile(project(":spring-orm"))
    compile(project(":spring-tx"))
    compile(project(":spring-web"))
    compile(project(":spring-context-indexer"))
    compile(project(":spring-expression"))
    compile(project(":spring-instrument"))
    compile(project(":spring-jcl"))
    compile(project(":spring-jms"))
    compile(project(":spring-messaging"))
    compile(project(":spring-oxm"))
    compile(project(":spring-test"))
    compile(project(":spring-webflux"))
    compile(project(":spring-websocket"))
    testImplementation 'javax.servlet:javax.servlet-api:3.1.0'
//    compile 'javax.servlet.jsp.jstl:jstl:1.2'
    compile 'org.apache.taglibs:taglibs-standard-spec:1.2.5'
    compile 'org.apache.taglibs:taglibs-standard-impl:1.2.5'
    testCompile group: 'junit', name: 'junit', version: '4.12'
    compile 'commons-fileupload:commons-fileupload:1.4'
    compile 'com.fasterxml.jackson.core:jackson-databind:2.12.3'
    compile 'com.fasterxml.jackson.core:jackson-annotations:2.12.3'
    compile 'com.fasterxml.jackson.core:jackson-core:2.12.3'
}

五、Spring内部实现类依赖

　　spring.handlers详情如下

http\://www.springframework.org/schema/mvc=org.springframework.web.servlet.config.MvcNamespaceHandler
http\://www.springframework.org/schema/context=org.springframework.context.config.ContextNamespaceHandler
http\://www.springframework.org/schema/jee=org.springframework.ejb.config.JeeNamespaceHandler
http\://www.springframework.org/schema/lang=org.springframework.scripting.config.LangNamespaceHandler
http\://www.springframework.org/schema/task=org.springframework.scheduling.config.TaskNamespaceHandler
http\://www.springframework.org/schema/cache=org.springframework.cache.config.CacheNamespaceHandler

六、jsp页面

　　userlist.jsp详情如下

<%--
  Created by IntelliJ IDEA.
  User: p'c
  Date: 2021/1/31
  Time: 0:50
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<h2>This is SpringMVC demo page</h2>
<c:forEach items="${users}" var="user">
   <c:out value="${user.name}"/><br/>
</c:forEach>
</body>
</html>

七、项目结构

八、调试问题

　　SpringMVC的请求只有第一次有效，之后就不起作用了

　　在实际的调试过程中，跳到下一个断点采用的是ALT+F9,IDEA界面如下，会导致SpringMVC后续请求到达不了断点。

解决方案：

　　使用快捷键F9，跳到下一个断点可解决此问题。