android 异步post发送请求获取json

【核心代码】

/**
 * PostToService.java [V 1.0.0]
 * classes : com.example.ahttptest.PostToService
 * 罗彪   Create at 2014年10月15日 下午1:18:07
 */
package com.example.ahttptest;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.URI;
import java.util.ArrayList;
import java.util.Map;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.multipart.FilePart;
import org.apache.commons.httpclient.methods.multipart.Part;
import org.apache.commons.httpclient.methods.multipart.StringPart;
import org.apache.commons.httpclient.params.HttpMethodParams;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.SerializableEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.CoreConnectionPNames;
import org.apache.http.util.EntityUtils;

import android.content.Context;
import android.os.Handler;
import android.os.Message;



public class PostToService {

	private Map<String, String> valueMap;
	private String url;
	private Context mContext;
	
	public PostToService(Context mContext, Map<String, String> valueMap,String url) {
		mContext = this.mContext;
		valueMap = this.valueMap;
		url = this.url;
	}

	public String PostRequest(Context mContext, Map<String, String> valueMap,
			String url) throws FileNotFoundException {

			HttpClient client = new HttpClient();
			PostMethod filePost = new PostMethod(url);
			filePost.getParams().setParameter(HttpMethodParams.HTTP_CONTENT_CHARSET, "utf-8");
			try {
					if(valueMap!=null){ 
					for (Map.Entry<String, String> map : valueMap.entrySet()) {
						if (null != map.getValue()) {
							filePost.addParameter(map.getKey(), map.getValue());
						}
					}
					}
				int status = client.executeMethod(filePost);
				if (status != 200) {
					return null;
				} else {
					return filePost.getResponseBodyAsString();
				}
			} catch (HttpException e) {
				e.printStackTrace();
				return null;
			} catch (IOException e) {
				e.printStackTrace();
				return null;
			} catch (Exception e) {
				e.printStackTrace();
				return null;
			}
	}


	private Context getApplicationContext() {
		// TODO Auto-generated method stub
		return null;
	}

}