httpclient使用

注意：HttpPost请求不能处理重定向转发事件。需要手动的去做。

如果要模拟登陆后的操作，则在请求中加入JSESSIONID就可以了

httpGet.setHeader("Cookie" , "JSESSIONID=432423432907427987EHLJ42"); 就可以了

package com.zf.test;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;


public class HttpClientUtils {

	/**
	 * 发送GET请求，携带参数
	 * @param url
	 * @param params
	 * @return  
	 * @throws Exception
	 */
	public static HttpEntity sendGetRequest(String url , Map<String , String> params ) throws Exception{
		final StringBuffer tmp  = new StringBuffer(url); ;
		if(params != null){
			Set<Entry<String, String>> paramset = params.entrySet();
			if(paramset.size() > 0){
				tmp.append("?");
				int totalLen = paramset.size() , index = 0 ;
				for (Entry<String, String> entry : paramset) {
					tmp.append(entry.getKey() + "=" + entry.getValue());
					if(++index <  totalLen){
						tmp.append("&"); 
					}
				}
			}
		}
		HttpClient httpClient = new DefaultHttpClient();
		HttpGet httpGet = new HttpGet(tmp.toString());
		HttpResponse response = httpClient.execute(httpGet);
		return response.getEntity();
	}


	/**
	 * 发送POST请求
	 * @param url
	 * @param parmas
	 * @return
	 * @throws Exception
	 */
	public static HttpEntity sendPostRequest(String url , Map<String , String> params) throws Exception{
		HttpClient httpClient = new DefaultHttpClient();
		List<NameValuePair> listParams = new ArrayList<NameValuePair>();
		if(params != null){
			Set<Map.Entry<String, String>> set = params.entrySet();
			for (Entry<String, String> entry : set) {
				listParams.add( new BasicNameValuePair(entry.getKey(), entry.getValue()));
			}
		}
		HttpPost httpPost = new HttpPost(url);  
		httpPost.setEntity(new UrlEncodedFormEntity(listParams , "utf-8"));
		HttpResponse reponse = httpClient.execute(httpPost) ;     
		
		return  reponse.getEntity();
	}

	/**
	 * 下载文件
	 * @param path	文件URL
	 * @param savePath	保存路径
	 * @param fileName	文件名
	 */
	public static void downloadFile(String path , String savePath , String fileName) throws Exception{
		HttpClient httpClient = new DefaultHttpClient();
		HttpGet httpGet = new HttpGet(path);
		HttpResponse response = httpClient.execute(httpGet);
		File dir = new File(savePath);
		if(!dir.exists())dir.mkdirs();
		File saveFile = new File(dir , fileName);
		BufferedInputStream  bis = new BufferedInputStream(response.getEntity().getContent());
		BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(saveFile));
		byte tmp[] = new byte[1024];
		int len = 0 ;
		while((len = bis.read(tmp)) != -1){ 
			bos.write(tmp, 0 , len);
		}
		bis.close();
		bos.flush() ; bos.close();
	}
	

	/**
	 * 利用jdk提供的HttpUrlConnect发起Post请求
	 * @return	
	 */
	public static InputStream sendPostRequestByUrlConnect(String path , Map<String , String> params)throws Exception{
		URL url = new URL(path);
		HttpURLConnection hul = (HttpURLConnection) url.openConnection();
		hul.setRequestMethod("POST");
		hul.setDoOutput(true);   //post 方式   
		hul.setDoInput(true);   
		if(params != null){
			Set<Entry<String, String>> paramSet = params.entrySet() ;         
			//加入参数
			StringBuilder paramsStr = new StringBuilder();
			String paramss = null;
			for (Entry<String, String> entry : paramSet) {     
				paramsStr.append(entry.getKey()).append("=").append(entry.getValue()).append("&");
			}    
			if(paramsStr.length() > 0)
				paramss = paramsStr.substring(0, paramsStr.length() - 1);  
			hul.getOutputStream().write(paramss.getBytes());   
		}
		hul.getOutputStream().flush();
		hul.getOutputStream().close();
		return hul.getInputStream();
	}

	/**
	 * 将输入流转换为字符串
	 * @param is
	 * @return
	 * @throws Exception
	 */
	public static String inputToString(InputStream is)throws Exception{
		StringBuffer sb = new StringBuffer("");
		String line = null;
		BufferedReader br = new BufferedReader(new InputStreamReader(is));
		while((line = br.readLine()) != null){
			sb.append(line + "\r\n");
		}
		return sb.toString();
	}

	/**
	 * 将HttpEntity对象转换为字符串
	 * @param entity
	 * @return
	 * @throws Exception
	 */
	public static String entityToString(HttpEntity entity) throws Exception{
		return entity == null ? 
				null:EntityUtils.toString(entity , "utf-8"); 
	}


}