SpringMVC之“HelloWorld”起步

川长思鸟来 2022-06-11 08:42 138阅读 0赞

***添加jar包***  
在eclipse中创建一个web应用程序后，向“WEB-INF\\lib”中添加以下SpringMVC必须的jar包：  
\- commons-logging-1.2.jar  
\- spring-aop-4.3.10.RELEASE.jar  
\- spring-beans-4.3.10.RELEASE.jar  
\- spring-context-4.3.10.RELEASE.jar  
\- spring-core-4.3.10.RELEASE.jar  
\- spring-expression-4.3.10.RELEASE.jar  
\- spring-web-4.3.10.RELEASE.jar  
\- spring-webmvc-4.3.10.RELEASE.jar  
![这里写图片描述][SouthEast]

***配置DispatcherServlet***  
在web.xml中配置DispatcherServlet

<?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_3_0.xsd" id="WebApp_ID" version="3.0">
      <display-name>SpringMVC</display-name>
        <servlet>
          <servlet-name>HelloWeb</servlet-name>
          <servlet-class>
             org.springframework.web.servlet.DispatcherServlet
          </servlet-class>
          <init-param>
          <param-name>contextConfigLocation</param-name>
          <param-value>classpath:spring.xml</param-value>
          </init-param>
          <load-on-startup>1</load-on-startup>
       </servlet>
    
       <servlet-mapping>
          <servlet-name>HelloWeb</servlet-name>
          <url-pattern>/</url-pattern>
       </servlet-mapping>
    </web-app>

*  init-param：代表初始化参数，其中定义了spring的配置文件为classpath下的spring.xml;
 *  load-on-startup：表示这个Servlet是这个项目在被加载时创建

***编写请求处理器***  
请求处理器类：  
![这里写图片描述][SouthEast 1]

package com.gisxx.handlers;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    @Controller
    public class HelloWorld { 
    
        @RequestMapping("/helloworld")
        public String hello(){
    
            System.out.println("hello,GISXXCOM!!");
            return "success";
        }
    }

*  `@Controller`：将类标识为控制器；
 *  `@RequestMapping("/helloworld")`：映射请求路径为/helloworld;

编写写处理器配置文件。  
因为在web.xml中指定了spring配置文件位置，所以在src中新建spring.xml文件

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" 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-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">
    
       <context:component-scan base-package="com.gisxx.handlers" />
    
       <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
          <property name="prefix" value="/WEB-INF/jsp/" />
          <property name="suffix" value=".jsp" />
       </bean>
    
    </beans>

*  `context:component-scan`:指定自动扫描包；
 *  `bean`：配置视图解析器。prefix代表请求返回结果的前缀，suffix代表返回后缀

***编写视图页面***  
在WebRoot根目录下新建index.jsp请求页面

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
    <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %>
    
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
      <head>
        <base href="<%=basePath%>">
    
        <title>My JSP 'index.jsp' starting page</title>
        <meta http-equiv="pragma" content="no-cache">
        <meta http-equiv="cache-control" content="no-cache">
        <meta http-equiv="expires" content="0">    
        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
        <meta http-equiv="description" content="This is my page">
        
      </head>
    
      <body>
        <a href="helloworld">hello world</a>
      </body>
    </html>

在控制器类中指定了请求路径为/helloworld，所以这里a标签的链接可以直接为“helloworld”

在WEB-INF中新建jsp文件夹，再在其中新建返回页面success.jsp（在控制器配置文件spring.xml中指定了前缀和后缀，再加上控制器返回字符串组成完整结果）

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %>
    
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
      <head>
        <base href="<%=basePath%>">
    
        <title>My JSP 'success.jsp' starting page</title>
    
        <meta http-equiv="pragma" content="no-cache">
        <meta http-equiv="cache-control" content="no-cache">
        <meta http-equiv="expires" content="0">    
        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
        <meta http-equiv="description" content="This is my page">
        
    
      </head>
    
      <body>
       <h1> 微信公众号：GISXXCOM
      </body>
    </html>

在服务器中运行后，点击index.jsp超链接可以条状到success.jsp页面，控制台返回：hello,GISXXCOM

本文首发于微信公众号：GISXXCOM  
![这里写图片描述][SouthEast 2]

[SouthEast]: /images/20220611/5ce4e396d5a44e38979a886d83cb4ec3.png
[SouthEast 1]: /images/20220611/318e4cc819f2486e8049dc7d902a65a5.png
[SouthEast 2]: /images/20220611/95715e43a09d453fb9f5d31846d91430.png