SpringMVC通过实体类返回json格式的字符串,并在前端显示

一.除了搭建springmvc框架需要的jar包外,还需要这两个jar包

jackson-core-asl-1.9.2.jar和jackson-mapper-asl-1.9.2.jar

二.web,.xml配置

classpath:spring-servlet.xml指定springmvc配置文件的位置

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
	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_2_5.xsd">  

   <servlet>
    <servlet-name>spring</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
     <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:spring-servlet.xml</param-value>
    </init-param>
    <!-- 可以自定义servlet.xml配置文件的位置和名称，默认为WEB-INF目录下，名称为[<servlet-name>]-servlet.xml，如spring-servlet.xml
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/spring-servlet.xml</param-value>  默认
    </init-param>
    -->
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>spring</servlet-name>
    <url-pattern>*.do</url-pattern>
</servlet-mapping>

</web-app>

三.spring-servlet.xml配置

通过此配置,将实体类自动返回为json格式的数据

<?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:p="http://www.springframework.org/schema/p"
    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-3.2.xsd
       http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.2.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">
     <!-- 启用spring mvc 注解 -->
    <context:annotation-config />

    <!-- 设置使用注解的类所在的jar包 -->
    <context:component-scan base-package="me.mvc,me.base"></context:component-scan>

    <!-- 完成请求和注解POJO的映射 -->
  <!--   <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" /> -->

    <!-- 对转向页面的路径解析。prefix：前缀， suffix：后缀 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix="/jsp/" p:suffix=".jsp" />

   <!-- 通过实体类返回json格式数据的关键配置 -->

<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter"> <property name="messageConverters"> <list> <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"> <property name="supportedMediaTypes"> <list> <!--返回字符串格式json--> <value>application/json;charset=UTF-8</value> </list> </property> </bean> </list> </property> </bean> <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> <property name="maxUploadSize" value="102400000"></property> </bean> </beans>

四,后台java代码

package me.mvc;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import me.mvc.service.testmvcDao;
import net.sf.json.JSONArray;

import org.apache.struts2.ServletActionContext;
import org.springframework.http.HttpRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import org.springframework.web.servlet.ModelAndView;

@Controller
@RequestMapping("/mvc/*")
public class testmvc {

    @RequestMapping(method=RequestMethod.GET,value="/hello22index.do")//第一步访问hello2页面
      public String index2() {

      return "hello2";
  }
    @ResponseBody
    @RequestMapping(method=RequestMethod.POST,value="/hello22.do")//第二步前台发送ajax请求调用此方法并返回json数据
      public User index2post(String testname1 ,HttpServletResponse response) throws IOException {

        System.out.println("*************:"+testname1);

        User u=new User();
        u.setUsername("name");
        u.setUserpassword("pass");
        return u;
}

}

五.前端页面

该方法sendajax()将向后台发送请求,调用index2post()方法,返回json数据格式

<%@ 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>
   <script type="text/javascript" src="../../js/jquery-1.12.0.js"></script>
    <base href="<%=basePath%>">

    <title>My JSP ‘hello2.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">

 <script type="text/javascript" src="<%=path%>/js/jquery-1.12.0.js"></script></head>

  <body>

      <input type="text" name="testname" id="testname1">

       <input type="button" value="ajax提交" onclick="sendajax()">

</form>
  </body>
  <script type="text/javascript">
   function  sendajax()
   {
	   var testname1=$("#testname1").val();
	   alert(testname1);
	   $.ajax({
	        type: "post",
	        url: "<%=path%>/mvc/hello22.do",
	        data: {testname1:testname1},
	        dataType: "json",
	        success: function (data) {
	      	 alert(data.username);

		     },
	        error: function (XMLHttpRequest, textStatus, errorThrown) {
	         alert("系统繁忙,请稍后重试!");
	  }
	});
   }
  </script>
</html>