fastjson开发学习(一)---把对象封装成json。

首先需要下载fastjson的jar包，官方也提供了下载地址和源码。

fastjson: http://www.oschina.net/p/fastjson

fastjson 是一个性能很好的 Java 语言实现的 JSON 解析器和生成器，来自阿里巴巴的工程师开发。

主要特点：

快速FAST (比其它任何基于Java的解析器和生成器更快，包括 jackson）
强大（支持普通JDK类包括任意Java Bean Class、Collection、Map、Date或enum）
零依赖（没有依赖其它任何类库除了JDK）

然后创建一个Web工程，并且创建一个servlet类【FirstServlet.java】

代码如下：

package com.fastjson.test;
 
import java.io.IOException;
import java.io.PrintWriter;
 
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import com.alibaba.fastjson.JSON;
 
public class FirstServlet extends HttpServlet {
 
	/**
	 * Constructor of the object.
	 */
	public FirstServlet() {
		super();
	}
 
	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}
 
	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request,HttpServletResponse response)
			throws ServletException,IOException {
		this.doPost(request,response);
//
//		response.setContentType("text/html");
//		PrintWriter out = response.getWriter();
//		out
//				.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
//		out.println("<HTML>");
//		out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
//		out.println("  <BODY>");
//		out.print("    This is ");
//		out.print(this.getClass());
//		out.println(",using the GET method");
//		out.println("  </BODY>");
//		out.println("</HTML>");
//		out.flush();
//		out.close();
	}
 
	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request,IOException {
		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
		Group group = new Group();
		group.setId(0L);
		group.setName("admin");
 
		User guestUser = new User();
		guestUser.setId(2L);
		guestUser.setName("guest");
 
		User rootUser = new User();
		rootUser.setId(3L);
		rootUser.setName("root");
 
		group.getUsers().add(guestUser);
		group.getUsers().add(rootUser);
		String jsonString = JSON.toJSONString(group);
		System.out.println("调用后台");
		out.println(jsonString);
		out.flush();
		out.close();
		
	}
 
	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occurs
	 */
	public void init() throws ServletException {
		// Put your code here
	}
 
}

然后配置【web.xml】

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 
	xmlns="http://java.sun.com/xml/ns/j2ee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
	http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>FirstServlet</servlet-name>
    <servlet-class>com.fastjson.test.FirstServlet</servlet-class>
  </servlet>
 
  <servlet-mapping>
    <servlet-name>FirstServlet</servlet-name>
    <url-pattern>/servlet/first</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

jsp页面上（整理也可以用Html页面）

<%@ 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 'json.jsp' starting page</title>
    
	<@R_502_338@ http-equiv="pragma" content="no-cache">
	<@R_502_338@ http-equiv="cache-control" content="no-cache">
	<@R_502_338@ http-equiv="expires" content="0">    
	<@R_502_338@ http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<@R_502_338@ http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
	<script type="text/javascript" src="js/jquery-1.4.2.min.js"></script>
	<script type="text/javascript">
	$(function(){
	 $('#mylink').click(function(){
	 	alert("ok");
		  $.get("http://192.168.0.101:8080/Test/servlet/first",function(data){
	 	 alert(data);
	 	  $('#result').text(data);
	   return;
	  });
	  
	 });
	});
	
	
	
</script>
	
  </head>
  
  <body>
  
<a href="javascript:void(0)" id="mylink">链接</a>
<input type="button" id="mybtn" value="提交">
<div id="result">
 
</div>
 
  </body>
</html>

fastjson开发学习(一)---把对象封装成json。

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