Spring3.0实现REST实例

Spring从3.0开始将全面支持rest。不得不感叹Spring的强大。

项目结构：


    第一步：配置web.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee  
    http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
    <display-name></display-name>
    <context-param>
        <!--rest配置文件的路径，貌似不配置也是加载这个地址，这个地方有点疑问，大家指点指点 -->
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/rest-servlet.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <servlet>
        <!-- 配置一个Servlet，有这个Servlet统一调度页面的请求 -->
        <servlet-name>rest</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>2</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>rest</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    <welcome-file-list>
        <welcome-file>/index.jsp</welcome-file>
    </welcome-file-list>
</web-app>

 
   第二步：配置rest-servlet.xml这个文件

<?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:jee="http://www.springframework.org/schema/jee"
    xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-2.5.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd"
    default-lazy-init="true">
    <description>Spring公共配置</description>
    <!--检测注解 -->
    <context:component-scan base-package="com.bijian" />
    <bean     class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />
    <bean      class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
    <!-- 注册视图解析器，说白了就是根据返回值指定到某个页面 -->
    <bean id="viewResolver"     class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass"
            value="org.springframework.web.servlet.view.JstlView" />
        <property name="prefix" value="/"></property> <!--页面文件的路径，在根目录下 -->
    </bean>
</beans>

 
    第三步：具体实现类

package com.bijian.controller;

import java.io.IOException;
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import org.springframework.stereotype.Controller; 
import org.springframework.web.bind.annotation.PathVariable; 
import org.springframework.web.bind.annotation.RequestMapping; 
import org.springframework.web.bind.annotation.RequestMethod; 

@Controller 
@RequestMapping("/simple") 
public class SimpleController {
 
    //映射路径/simple/index当访问这个路径时，执行这个方法 
    @RequestMapping("/index") 
    public String index(HttpServletRequest request ,HttpServletResponse response){
              //response,request会自动传进来 
        request.setAttribute("message", "Hello,这是一个Spring3 REST的实例！"); 
        return "index.jsp"; 
    }

    //根据ID获取不同的内容，通过@PathVariable 获得属性 
    @RequestMapping(value="/{id}",method=RequestMethod.GET) 
    public String get(@PathVariable String id,HttpServletRequest request ,HttpServletResponse response) throws IOException{ 
        request.setAttribute("message", "Hello,这是一个Spring3 REST的实例！<br/>ID:"+id+"");
       //response.getWriter().write("You put id is : "+id);
        return "index.jsp";
        //return null; 
    }
}

 

    第四步：index.jsp页面

<%@ page language="java" pageEncoding="UTF-8"%> 
<html> 
  <head> 
    <title>Spring3 RESTful</title> 
   </head> 
  <body>
    ${message}
   </body>
</html>

 

        在浏览器中输入：http://localhost:8080/SpringREST2/simple/index，就可以看到效果。


        也可以在页面输入不同的参数，获得不同的内容，输入地址：http://localhost:8080/SpringREST2/simple/abc，这次执行的就是get方法，通过注解获取ID值，效果：


        关于Spring rest 对于Ajax的支持，其实响应Ajax就是通过response返回一个字符串到页面，既然能获得response对象，那问题就迎刃而解了，我们改造下get方法：

    //根据ID获取不同的内容，通过@PathVariable 获得属性 
    @RequestMapping(value="/{id}",method=RequestMethod.GET) 
    publicString get(@PathVariableString id,HttpServletRequest request ,HttpServletResponse response) throws IOException{ 
        //request.setAttribute("message", "Hello,这是一个Spring3 REST的实例！<br/>ID:"+id+"");
    response.getWriter().write("You put id is : "+id);
        //return "index.jsp";
        return null; 
    }

 
        改造index.jsp页面：

<%@ page language="java" pageEncoding="UTF-8"%> 

<html> 
  <head> 
    <title>Spring3 RESTful</title> 
    <SCRIPT TYPE="text/javascript"> 
            function go(value){ 
                var url = "/SpringREST2/simple/"+value+"/"; 
                var request =  newXMLHttpRequest(); 
                request.open("GET", url, true); 
                request.setRequestHeader("Content-Type","application/x-javascript;"); 
                request.onreadystatechange = function() { 
                    if (request.readyState == 4) { 
                        if (request.status == 200){ 
                            if (request.responseText) {                               document.getElementByIdx_x_x_x_x("text").innerHTML = request.responseText; 
                            }
                        } 
                    }
                }; 
                request.send(null); 
            } 
        </SCRIPT> 
  </head> 

  <body> 
    ${message} 
    <br>
    请输入您将访问的Id标识:<input id="id" type="text" size="7"><input type="button" value="Go" onclick="go(document.getElementByIdx_x_x_x_x('id').value)"> 
    <div id="text"></div> 
  </body> 
</html>

 
  访问http://localhost:8080/SpringREST2/simple/index，在页面里的输入框中输入值，可以看到返回的数据：