SpringMVC入门案例/RequestMapping注解详解

SpringMVC入门案例/RequestMapping注解详解

项目结构

配置文件

1. pom.xml

   <?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>com.xiaoge</groupId>
     <artifactId>springmvc_start</artifactId>
     <version>1.0-SNAPSHOT</version>
     <packaging>war</packaging>
   
     <name>springmvc_start Maven Webapp</name>
     <!-- FIXME change it to the project's website -->
     <url>http://www.example.com</url>
   
     <properties>
       <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
       <maven.compiler.source>1.7</maven.compiler.source>
       <maven.compiler.target>1.7</maven.compiler.target>
       <spring.version>5.0.2.RELEASE</spring.version>
     </properties>
   
     <dependencies>
       <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-context</artifactId>
         <version>${spring.version}</version>
       </dependency>
       <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-web</artifactId>
         <version>${spring.version}</version>
       </dependency>
       <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-webmvc</artifactId>
         <version>${spring.version}</version>
       </dependency>
       <dependency>
         <groupId>javax.servlet</groupId>
         <artifactId>servlet-api</artifactId>
         <version>2.5</version>
         <scope>provided</scope>
       </dependency>
       <dependency>
         <groupId>javax.servlet.jsp</groupId>
         <artifactId>jsp-api</artifactId>
         <version>2.0</version>
         <scope>provided</scope>
       </dependency>
     </dependencies>
   
     <build>
       <finalName>springmvc_start</finalName>
       <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
         <plugins>
           <plugin>
             <artifactId>maven-clean-plugin</artifactId>
             <version>3.1.0</version>
           </plugin>
           <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
           <plugin>
             <artifactId>maven-resources-plugin</artifactId>
             <version>3.0.2</version>
           </plugin>
           <plugin>
             <artifactId>maven-compiler-plugin</artifactId>
             <version>3.8.0</version>
           </plugin>
           <plugin>
             <artifactId>maven-surefire-plugin</artifactId>
             <version>2.22.1</version>
           </plugin>
           <plugin>
             <artifactId>maven-war-plugin</artifactId>
             <version>3.2.2</version>
           </plugin>
           <plugin>
             <artifactId>maven-install-plugin</artifactId>
             <version>2.5.2</version>
           </plugin>
           <plugin>
             <artifactId>maven-deploy-plugin</artifactId>
             <version>2.8.2</version>
           </plugin>
         </plugins>
       </pluginManagement>
     </build>
   </project>
   
   

2. web.xml

   <!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>
   
       <!-- 指定加载的配置文件 ，通过参数contextConfigLocation加载-->
       <init-param>
   
         <param-name>contextConfigLocation</param-name>
   
         <param-value>classpath:spring.xml</param-value>
   
       </init-param>
   
       <!-- 当启动服务器的时候创建servlet对象 -->
       <load-on-startup>1</load-on-startup>
   
     </servlet>
   
     <servlet-mapping>
   
       <!-- 前端控制器 -->
       <servlet-name>dispatcherServlet</servlet-name>
   
       <!-- 这里是/ 拦截所有的请求 -->
       <url-pattern>/</url-pattern>
   
     </servlet-mapping>
   
   
   </web-app>
   
   

3. spring.xml

   <?xml version="1.0" encoding="UTF-8"?>
   <beans xmlns="http://www.springframework.org/schema/beans"
          xmlns:mvc="http://www.springframework.org/schema/mvc"
          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
           https://www.springframework.org/schema/beans/spring-beans.xsd
           http://www.springframework.org/schema/mvc
           https://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
   
       <!-- 开启注解扫描 -->
       <context:component-scan base-package="com.xiaoge"></context:component-scan>
   
       <!-- 视图解析器对象 -->
       <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
           <!-- 指定控制器对象返回的jsp名称, 去哪个目录下寻找 -->
           <property name="prefix" value="/WEB-INF/pages/"></property>
           <property name="suffix" value=".jsp"></property>
       </bean>
   
       <!--开启springMVC框架注解的支持-->
       <mvc:annotation-driven />
   </beans>
   

控制器

1. HelloController**(重点注释-解释RequestMapping注解)**

   package com.xiaoge.controller;
   
   import org.springframework.stereotype.Controller;
   import org.springframework.web.bind.annotation.RequestMapping;
   import org.springframework.web.bind.annotation.RequestMethod;
   
   /**
    * 控制器类
    *
    * @RequestMapping注解:
    *      作用:
    *          放在类上一级访问目录
    *          放在方法上二级访问目录
    *      属性:
    *          value: 用于指定请求的url. 它和path属性的作用是一样的
    *          method: 用于指定请求的方式
    *          params: 用于指定限制请求参数的条件. 它支持简单的表达式.
    *                  要求请求参数的key和value必须和配置的一模一样
    *                  列:
    *                      params = {"accountName"}, 标识请求参数必须有accountName
    *                      params = {"money!100"}, 标识请求参数中money不能是100.
    *          headers: 用于指定配置请求头的条件.
    *      注意:
    *          以上四种属性只要出现2个或以上是, 他们的关系是与的关系.
    */
   @Controller
   @RequestMapping(path = "/user")
   public class HelloController {
       /*
           SpringMVC中的注解
           设置请求的路径
        */
       @RequestMapping(path = "/sayHello")
       public String sayHello(){
           System.out.println("Spring MVC");
           return "success";
       }
   
       /**
        * 测试RequestMapping注解
        * @return
        */
       @RequestMapping(value = "/testRequestMapping", method = {RequestMethod.POST}, params = {"username"}, headers = {"accept"})
       public String testRequestMapping(){
           System.out.println("测试testRequestMapping注解....");
           return "success";
       }
   
   }
   
   

前台页面

1. index.jsp

   <%--
     Created by IntelliJ IDEA.
     User: xiaoge
     Date: 2020/4/19
     Time: 下午1:59
     To change this template use File | Settings | File Templates.
   --%>
   <%@ page contentType="text/html;charset=UTF-8" language="java" %>
   <html>
   <head>
       <title>首页</title>
   </head>
   <body>
   <a href="user/sayHello">RequestMapping</a>
   </body>
   </html>
   
   

2. success.jsp

   <%--
     Created by IntelliJ IDEA.
     User: xiaoge
     Date: 2020/4/19
     Time: 下午1:59
     To change this template use File | Settings | File Templates.
   --%>
   <%@ page contentType="text/html;charset=UTF-8" language="java" %>
   <html>
   <head>
       <title>success</title>
   </head>
   <body>
       <h3>成功</h3>
   </body>
   </html>