Httpclient

package com.http.utils;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;

import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;


public class Httpclient {
    public static String sendHttpClientPost(String path,Map<String, String> map,String encode ) throws UnsupportedEncodingException{
        List<NameValuePair> list=new ArrayList<NameValuePair>(); 
        if(map!=null&&!map.isEmpty()){
            for(Map.Entry<String, String> entry:map.entrySet()){
                list.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
            }
        }
        CloseableHttpClient httpClient=null;
        try {
            //实现将请求的参数封装到表单中
            UrlEncodedFormEntity entity=new UrlEncodedFormEntity(list, encode);
            //以Post方式提交数据
            HttpPost httpPost=new HttpPost(path);
            //设置参数
            httpPost.setEntity(entity);
            //HttpClients工厂创建默认HttpClient实例
            httpClient=HttpClients.createDefault();
            //public CloseableHttpResponse execute方法
            //发送请求返回CloseableHttpResponse
            HttpResponse httpResponse=httpClient.execute(httpPost);
            System.out.println(httpResponse.getEntity().toString());
            //获取响应状态码
            int responsecode=httpResponse.getStatusLine().getStatusCode();
            System.out.println(responsecode);
            if(responsecode==200){
            return changeInputStream(httpResponse.getEntity().getContent(), encode);
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            try {
                httpClient.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return null;
    }
    /**
     * 强输入流转换为字符串输出到内存
     * @param inputStream
     * @param encode
     * @return
     */
    private static String changeInputStream(InputStream inputStream,String encode){
        ByteArrayOutputStream outputStream=new ByteArrayOutputStream();
        byte[] buffer=new byte[1024];
        int length=0;
        try {
            while(-1!=(length=inputStream.read(buffer))){
                outputStream.write(buffer, 0, length);
            }
            return new String(outputStream.toByteArray(), encode);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        return null;
    }
    public static void main(String[] args) {
        Map<String, String> parames=new HashMap<String,String>();
        parames.put("username", "admin");
        parames.put("password", "admin");
        String str = null;
        try {
            str = sendHttpClientPost("http://localhost:8080/login/loginServlet", parames, "utf-8");
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        System.out.println(str);
    }
}