http实现发送post请求，获取结果集

package com.ming;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Map;


public class HttpBaseUtil {

    
    /**
     * 向指定的url发送post方法,并获取放回值
     * @param url 发送的url
     * @param param 发送的参数 参数形式a=2&b=2
     * @param head 请求头设定
     */
    public static String sendPostUrl(String url,String param,Map<String, String> head) throws Exception{
        StringBuffer result=new StringBuffer();
        PrintWriter out =null;
        BufferedReader in=null;
        try {
            URL realUrl = new URL(url);
            // 打开和URL之间的连接
            HttpURLConnection  conn =(HttpURLConnection)realUrl.openConnection();
            // 设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent","Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            if(head!=null && !head.isEmpty()){
                for (String key:head.keySet()){
                    conn.setRequestProperty(key, head.get(key));
                }
            }
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 获取URLConnection对象对应的输出流
            out = new PrintWriter(new OutputStreamWriter(conn.getOutputStream(),"UTF-8"));
            // 发送请求参数
            out.print(param);
            // flush输出流的缓冲
            out.flush();
            // 定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(new InputStreamReader(conn.getInputStream(),"UTF-8"));
            String line;
            while ((line = in.readLine()) != null) {
                result.append(line);
            }
        } catch (Exception e) {
            throw new Exception("发送post出现异常."+e.getMessage());
        }
        return result.toString();
    }
    
}

import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.methods.HttpUriRequest;

import java.io.IOException;

public class LocalHttpClient {

    private static LocalHttpClient localHttpClient;
    protected HttpClient httpClient;

    private static int maxTotal = 100;
    private static int maxPerRoute = 10;
    public static void init(int maxTotal,int maxPerRoute){
        LocalHttpClient.maxTotal = maxTotal;
        LocalHttpClient.maxPerRoute = maxPerRoute;
    }

    public static LocalHttpClient getInstance(){
        if(localHttpClient != null){
            return localHttpClient;
        }else{
            localHttpClient = new LocalHttpClient();
            if(maxTotal > 0){
                localHttpClient.httpClient = HttpClientFactory.createHttpClient(maxTotal,maxPerRoute);
            }else{
                localHttpClient.httpClient = HttpClientFactory.createHttpClient();
            }
            return localHttpClient;
        }
    }

    public HttpResponse execute(HttpUriRequest request){
        try {
            return httpClient.execute(request);
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    public <T> T execute(HttpUriRequest request,ResponseHandler<T> responseHandler){
        try {
            return httpClient.execute(request, responseHandler);
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
}