21SpringMvc_异步发送表单数据到Bean，并响应JSON文本返回(这篇可能是最重要的一篇了) / 憋错料

这篇文章实现三个功能：1.在jsp页面点击一个按钮，然后跳转到Action,在Action中把Emp(int id ,String salary,Data data)这个实体变成JSON格式返回到页面上。

2.在jsp页面点击第二个按钮，然后跳转到Action,在Action中把List<Emp>这个集合变成JSON格式返回到页面上。

3.在jsp页面点击第三个按钮，然后跳转到Action,

List<Emp> empList = new ArrayList<Emp>();

Map<String,Object> map;

map.put("total",empList.size());
map.put("rows",empList);

在Action中把这个map变成JSON格式返回到页面上。

案例如下：

案例结构如下：

所用的代码文件：com.guigu.shen.Action11(实体类Emp.java；控制器类userAction.java;配置文件springmvc_11.xml);web.xml;bean2json.jsp;

第一步：先写bean2json.jsp

<%@ 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 ‘index.jsp‘ starting page</title>
          <script type="text/javascript" src="js/jquery-1.8.2.js"></script>
  </head>
  <body>
<input type="button" value="Emp转JSON"   /></p>
<input type="button" value="List<Emp>转JSON"   /></p>
<input type="button" value="Map<String,Object>"转JSON"/></p>

<!--Emp转JSON -->
<script type="text/javascript">
$(":button:first").click(
function()
{
var url="${pageContext.request.contextPath}/emp/bean2json.action";
var sendData=null;
//第一个参数是请求的网址，第二个参数是返回的状态，第三个是回调函数
$.post(url,sendData,function(backData,textStaut,ajax){
alert(ajax.responseText);
});
}
);
</script>

  <!-- Map<String,Object>转JSON  这个非常重要-->
   <script type="text/javascript">
           $(":button:last").click(function(){
               var url = "${pageContext.request.contextPath}/emp/map2json.action";
               var sendData = null;
            $.post(url,sendData,function(backData,textStaut,ajax){
                alert(ajax.responseText);
            });
           });
   </script>

   <!-- List<Emp>转JSON -->
   <script type="text/javascript">
           $(":button:eq(1)").click(function(){
               var url = "${pageContext.request.contextPath}/emp/listbean2json.action";
               var sendData = null;
            $.post(url,sendData,function(backData,textStaut,ajax){
                alert(ajax.responseText);
            });
           });
   </script>
  </body>
</html>

第二步：写web.xml文件

<?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_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>SpringMvc_10day_self</display-name>
  <!-- Spring提供了一个Filter专门用来解决Post提交中文的乱码问题 -->
   <filter>
     <filter-name>CharacterEncodingFilter</filter-name>
     <filter-class>
 org.springframework.web.filter.CharacterEncodingFilter
 </filter-class>
 <init-param>
    <param-name>encoding</param-name>
    <param-value>UTF-8</param-value>
 </init-param>
</filter>
 <filter-mapping>
 <filter-name>CharacterEncodingFilter </filter-name>
 <url-pattern>/*</url-pattern>
 </filter-mapping>

  <servlet>
  <!--这个名字可以随便取得，但是这个名字取了之后，以后在 WEB-INF下面创建SpirngMVC的配置文件是，命名必须以这个开头，

  所以这里取名叫做DispatcherServlet，那么之后的xml文件取名必须为DispatcherServlet-servlet.xml（一个字都不能差）

  -->
  <servlet-name>DispatcherServlet</servlet-name>
  <servlet-class> org.springframework.web.servlet.DispatcherServlet</servlet-class>
 <!-- 通知DispatcherServlet去指定目录下找到springmvc.xml配置文件 -->
 <!--
 注意这里的  <param-name>contextConfigLocation</param-name>一个字母都不能有错
 一旦有错就会去WEB-INF下面去找
  -->
          <init-param>
               <param-name>contextConfigLocation</param-name>
              <param-value>classpath:spring.xml</param-value>
          </init-param>
 </servlet>
 <servlet-mapping>
   <servlet-name>DispatcherServlet</servlet-name>
    <url-pattern>*.action</url-pattern>

 </servlet-mapping>

  <welcome-file-list>

    <welcome-file>index.jsp</welcome-file>

  </welcome-file-list>
</web-app>

第三步：写spring.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:aop="http://www.springframework.org/schema/aop"
      xmlns:tx="http://www.springframework.org/schema/tx"
      xmlns:mvc="http://www.springframework.org/schema/mvc"
      xsi:schemaLocation="
      http://www.springframework.org/schema/beans
      http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
      http://www.springframework.org/schema/context
      http://www.springframework.org/schema/context/spring-context-3.0.xsd
      http://www.springframework.org/schema/aop
      http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
      http://www.springframework.org/schema/tx
      http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
      http://www.springframework.org/schema/mvc
      http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"
>
<import resource="com/guigu/shen/Action11/springmvc_11.xml"/>
</beans>

第四步：springmvc_11.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:aop="http://www.springframework.org/schema/aop"
      xmlns:tx="http://www.springframework.org/schema/tx"
      xmlns:mvc="http://www.springframework.org/schema/mvc"
      xsi:schemaLocation="
      http://www.springframework.org/schema/beans
      http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
      http://www.springframework.org/schema/context
      http://www.springframework.org/schema/context/spring-context-3.0.xsd
      http://www.springframework.org/schema/aop
      http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
      http://www.springframework.org/schema/tx
      http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
      http://www.springframework.org/schema/mvc
      http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"
>
     <!-- 控制器(程序员)（必须配置） -->
<context:component-scan base-package="com.guigu.shen.Action11"/>
  <!-- 基于注解的映射器(可选)
  这个类和以前的xml方式的类不同，专门是注解用的
  -->
           <!--
           使用JSON的所要做的事情：
            1）导入jackson-core-asl-1.9.11.jar和jackson-mapper-asl-1.9.11.jar
            2）在业务方法的返回值和权限之间使用@ResponseBody注解表示返回值对象需要转成JSON文本
            3）在spring.xml配置文件中编写如下代码：
            <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
                <property name="messageConverters">
                        <list>
                            <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"/>
                        </list>
                </property>
            </bean>
        -->

       <!-- 注册适配器 -->
        <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
                <property name="messageConverters">
                        <list>
                            <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"/>
                        </list>
                </property>
        </bean>

</beans>

第五步：写com.guigu.shen.Action11下面的Emp.java和UserAction.java

package com.guigu.shen.Action11;

import java.util.Date;

public class Emp {
    private Integer id;
    private String username;
    private Double salary;
    private Date hiredate;
    public Emp(){}
    public Emp(Integer id, String username, Double salary, Date hiredate) {
        this.id = id;
        this.username = username;
        this.salary = salary;
        this.hiredate = hiredate;
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public Double getSalary() {
        return salary;
    }
    public void setSalary(Double salary) {
        this.salary = salary;
    }
    public Date getHiredate() {
        return hiredate;
    }
    public void setHiredate(Date hiredate) {
        this.hiredate = hiredate;
    }
}

package com.guigu.shen.Action11;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import org.omg.CORBA.PUBLIC_MEMBER;
import org.springframework.beans.propertyeditors.CustomDateEditor;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.ServletRequestDataBinder;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

/**
 *
 *
请求路径可以拆分为：根模块的名字+分模块的名字
就是相当于当访问http://127.0.0.1:8080:项目名/user/register时就会进入到
registerMethod方法。
 */
@Controller
@RequestMapping(value="/emp")//根模块的请求名字
public class UserAction {

    //bean转成json
@RequestMapping(method=RequestMethod.POST,value="/bean2json")//分模块的请求名字
/*
 *  @ResponseBody Emp 表示让springmvc将Emp对象转成JSON文本
 *
 */
public @ResponseBody Emp EmptoJson()
{
Emp emp=new Emp(1, "伤", 111.1, new Date());    

 return emp;
}

//list转成Json
@RequestMapping(method=RequestMethod.POST,value="/listbean2json")//分模块的请求名字

public @ResponseBody List<Emp> listbenatoJson()
{

            List<Emp> empList = new ArrayList<Emp>();
            empList.add(new Emp(1,"伤",7000D,new Date()));
            empList.add(new Emp(2,"伤",8000D,new Date()));
            empList.add(new Emp(3,"伤",9000D,new Date()));
            return empList;
}

//map转成json
@RequestMapping(value="/map2json")
public @ResponseBody Map<String,Object> map2json() throws Exception{

    List<Emp> empList = new ArrayList<Emp>();

    empList.add(new Emp(1,"伤",7000D,new Date()));
    empList.add(new Emp(2,"伤",8000D,new Date()));
    empList.add(new Emp(3,"伤",9000D,new Date()));

    Map<String,Object> map = new LinkedHashMap<String,Object>();

    map.put("total",empList.size());
    map.put("rows",empList);

    return map;
}

}

最后一步测试：

按钮如下：