Flex+Servlet实现JSON数据交互

1、FlexServlet

package com.ohgrateboy;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.json.JSONException;
import org.json.JSONObject;

public class FlexServlet extends HttpServlet {

	public FlexServlet() {
		super();
	}

	public void destroy() {
		super.destroy();
	}

	public void doGet(HttpServletRequest request,HttpServletResponse response)
			throws ServletException,IOException {
		doPost(request,response);
	}

	public void doPost(HttpServletRequest request,IOException {
		// 判断浏览器请求是否是JSON的类型/application/json
		if (request.getContentType().indexOf("application/json") == -1) {
			return;
		}

		String msg = "Success";
		int code = 200;

		JSONObject jsonReq = parseRequest(request);// 将页面JSON转换成Java JSON。
		JSONObject jsonRes = new JSONObject();// 实例化一个JSON格式的响应变量。

		String serviceId = "";
		if (!jsonReq.has("serviceId")) {// 判断该请求是否有serviceId标志
			code = 401;
			msg = "MissingServiceId";
		} else {
			try {
				serviceId = jsonReq.getString("serviceId");
				jsonRes.put("serviceId",serviceId);
				dispatch(jsonReq,jsonRes);
			} catch (JSONException e) {
				e.printStackTrace();
			}
		}
		writeToResponse(response,jsonRes);
	}

	private void dispatch(JSONObject jsonReq,JSONObject jsonRes)
			throws JSONException {
		String msg = "";
		int code = 200;
		System.out.println("ServiceId = "+jsonReq.getString("serviceId"));
		if(jsonReq.getString("serviceId").equalsIgnoreCase("simpleQuery")){
			new SimpleQuery().exec(jsonReq,jsonRes);
		}
		// sv = (Service) wac.getBean(jsonReq.getString("serviceId"));
		//实例化一个JavaBean处理请求
		// sv.execute(jsonReq,jsonRes);
	}
	// 从JSON Request获取JSON Data添加IP后封装新的Java版的JSON对象实例。
	public static JSONObject parseRequest(HttpServletRequest request) {
		try {
			String encoding = request.getCharacterEncoding();
			if (encoding == null) {
				encoding = "UTF-8";
			}
			InputStream ins = request.getInputStream();
			InputStreamReader insr = new InputStreamReader(ins,encoding);

			int readed = 0;
			int size = request.getContentLength();
			char[] buf = new char[size];

			while (readed < size) {
				int nextSize = size - readed;
				int nextReaded = insr.read(buf,readed,nextSize);
				if (nextReaded != -1) {
					readed += nextReaded;
				} else {
					break;
				}
			}
			System.out.println("Request JSON Value ="+ String.valueOf(buf));
			JSONObject jsonReq = new JSONObject(String.valueOf(buf));
			return jsonReq;
		} catch (Exception e) {
		}
		return new JSONObject();
	}
	public static void writeToResponse(HttpServletResponse response,JSONObject json) throws IOException {
		response.addHeader("content-type","text/javascript");
		OutputStreamWriter out = new OutputStreamWriter(response
				.getOutputStream(),"utf-8");
		out.write(json.toString());
		out.flush();
		out.close();
	}

	public void init() throws ServletException {
	}

}

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2、SimpleQuery

package com.ohgrateboy;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

public class SimpleQuery {

	public void exec(JSONObject jsonReq,JSONObject jsonRes) {

		JSONArray body = new JSONArray();
		try {
			jsonRes.put("body",body);

			JSONObject jsonRec = new JSONObject();
			body.put(jsonRec);
			jsonRec.put("id","1");
			jsonRec.put("name","三国演义");
			jsonRec.put("author","罗贯中");
			jsonRec.put("price","59.30");
		} catch (JSONException e) {
			e.printStackTrace();
		}
	}

}

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3、web.xml

<?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>FlexServlet</servlet-name>
    <servlet-class>com.ohgrateboy.FlexServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>FlexServlet</servlet-name>
    <url-pattern>/FlexServlet</url-pattern>
  </servlet-mapping>
</web-app>

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4、httpservice_json.mxml

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
	<mx:Script>
		<![CDATA[
			import mx.rpc.http.HTTPService;
			import com.bsoft.flex.util.JsonRequest;
			import mx.controls.*;
			import mx.collections.*;
			private function doQuery():void
			{
				var obj:Object;
				var cnd=[];
				obj={serviceId: "simpleQuery",otherServer:"http://localhost:8090/flexweb/FlexServlet"};
				JsonRequest.exec(obj,queryResultHandler);
			}
			public function queryResultHandler():void
			{
				var code:int=arguments[0];
				var rs:Array=arguments[2]["body"] as Array;
				var items:ArrayCollection=new ArrayCollection(rs);
				if (code > 300)
				{
					var alert:Alert;
					alert=Alert.show(arguments[1],"信息");
					return;
				}
				if (items)
				{
					this.bookGrid.dataProvider = items;
				}
			}
		]]>
	</mx:Script>
	
	<mx:DataGrid id="bookGrid">
		<mx:columns>
				<mx:DataGridColumn headerText="编号" dataField="id"/>
				<mx:DataGridColumn headerText="书名" dataField="name"/>
				<mx:DataGridColumn headerText="作者" dataField="author"/>
				<mx:DataGridColumn headerText="价格" dataField="price"/>
			</mx:columns>
	</mx:DataGrid>
	<mx:Button id="query" label="查  询" click="doQuery()" x="348" y="150"/>
</mx:Application>

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5、JsonRequest.as

package com.bsoft.flex.util
{
	import flash.events.HTTPStatusEvent;
	import com.adobe.serialization.json.JSON;
	import mx.rpc.events.ResultEvent;
	import mx.rpc.events.FaultEvent;
	import mx.rpc.http.*;
	import mx.controls.*;
	
	public class JsonRequest
	{
		private static const CONTENT_TYPE:String = "application/json";
		private static const METHOD:String = "POST";
		private static const RES_CODE:String = "x-response-code";
		private static const RES_MSG:String = "x-response-msg";
		private static var SERVER_URL:String = "http://localhost/IS/";
		
		public function JsonRequest()
		{
			return;
		}
		
		public static function set serverURL(url:String):void{
			SERVER_URL = url;
			return;
		}
		
		public static function exec(request:Object,fn:Function,arguments:Object=null,httpScope:Object=null):void{
			var msg:String;
			var code:int;
			var json:Object;
			var me:Object;
			var req:* = request;
			var callback:* = fn;
			var args:* = arguments;
			var scope:* = httpScope;
			if(!req.url){
			}
			var requestUrl:String;
			var conn:* = new HTTPService();
			conn.url = SERVER_URL+requestUrl;
			if(req.otherServer){
				conn.url= req.otherServer;
			}
			conn.method = METHOD;
			conn.contentType = CONTENT_TYPE;
			if(!scope){
			}
			me = conn;
			conn.addEventListener(ResultEvent.RESULT,function(event:ResultEvent):void
			{
				try{
					json = JSON.decode(event.result.toString());
					if(!json[RES_MSG])
					{
					}
					msg = "SUCCESS";
					if(!json[RES_CODE])
					{
					}
					code = 200;
					callback(code,msg,json);
				}
				catch(err:Error)
				{
					code = 500;
					msg = "服务器请求失败:[ParseResponseError]";
					try
					{
						callback.cal(me,code,json,args);
					}catch(err:Error){
					Alert.show(err.toString());
					}
					
				}
				
				return;
			}
			);
			conn.addEventListener(HTTPStatusEvent.HTTP_STATUS,function(event:HTTPStatusEvent):void
			{
				code = 504;
				msg = "服务器请求失败：[HTTPStatusEvent statusCode：]"+event.status+"]";
				json[RES_CODE] = code;
				json[RES_MSG] = msg;
				callback.call(me,args);
				return;
				
			}	
			);
			conn.addEventListener(FaultEvent.FAULT,function(event:FaultEvent):void
			{
				code = 505;
				msg = "服务器请求失败：[FaultEvent statusCode：]"+event.statusCode+"]";
				json[RES_CODE] = code;
				json[RES_MSG] = msg;
				callback.call(me,args);
				return;
			}	
			);
			conn.send(JSON.encode(req));
			return;
		}

	}
}

Tomcat控制台显示信息：

页面前端输出结果：