HttpClient4.3使用总结

1.Get

	public static String getResultWithGet(HttpServletRequest request, String url) throws Exception{
		String result =  null;
		HttpClient client =getClient(); 
		try{
			HttpGet get = new HttpGet(url);
			HttpResponse response = client.execute(get); 
			result = getResponseBodyAsString(response);
		}finally{
			client.getConnectionManager().shutdown();  
		}
		return result;
	}

2、Post

public static String getResultWithPost(HttpServletRequest request, String url) throws Exception{
		String json = null;
		HttpClient client =getClient(); 
		try{
			HttpPost post = new HttpPost(url);
			@SuppressWarnings("unchecked")
			Map map = request.getParameterMap();
			Set keySet = map.keySet();
			JSONObject jo = new JSONObject();
			for(String s : keySet){
				if(!"".equals(map.get(s)[0])){
					jo.element(s, map.get(s)[0]);
				}

			}
			StringEntity reqEntity = new StringEntity(jo.toString(),"UTF-8");
			reqEntity.setContentType("application/json");
			post.setEntity(reqEntity);
			HttpResponse response = client.execute(post);
			json = getResponseBodyAsString(response);
		}finally{
			client.getConnectionManager().shutdown();  
		}
		return json;
	}

3、Put

public static String getResultWithPut(HttpServletRequest request, String url) throws Exception{
		String json = null;
		HttpClient client =getClient(); 
		try{
			HttpPut put = new HttpPut（url);
			@SuppressWarnings("unchecked")
			Map map = request.getParameterMap();
			Set keySet = map.keySet();
			JSONObject jo = new JSONObject();
			for(String s : keySet){
				if(!"".equals(map.get(s)[0])){
					jo.element(s, map.get(s)[0]);
				}

			}
			StringEntity reqEntity = new StringEntity(jo.toString(),"UTF-8");
			reqEntity.setContentType("application/json");
			put.setEntity(reqEntity);
			HttpResponse response = client.execute(put);
			json = getResponseBodyAsString(response);
		}finally{
			client.getConnectionManager().shutdown();  
		}
		return json;
	}

4、Delete

public static String getResultWithDelete(HttpServletRequest request, String url) throws Exception{
		String result = null;
		HttpClient client =getClient(); 
		try{
			HttpDelete delete = new HttpDelete(url);
			HttpResponse response  = client.execute(delete);
			result = getResponseBodyAsString(response);
		}finally{
			client.getConnectionManager().shutdown();  
		}
		return result;
	}

5、getResponseBodyAsString

public static String getResponseBodyAsString(HttpResponse response) throws Exception {
		StringBuilder sb = new StringBuilder();
		HttpEntity httpEntity = response.getEntity();  
		if(httpEntity != null){
			httpEntity = new BufferedHttpEntity(httpEntity);  
		    InputStream is = httpEntity.getContent();  
		    BufferedReader br = new BufferedReader(new InputStreamReader(is,"UTF-8"));
		    String str;
		    while((str=br.readLine())!=null){
		    	sb.append(str);
		    }
		    is.close();
		}
		return sb.toString();
	}

6、文件上传

 public String uploadAttachment(HttpServletRequest request){
		String json = null;
		HttpClient client = TicketUtils.getClient(); 
		try {

			HttpPost post = new HttpPost(url);

			DiskFileItemFactory fac = new DiskFileItemFactory();
			ServletFileUpload upload = new ServletFileUpload(fac);
			upload.setHeaderEncoding("UTF-8");
			@SuppressWarnings("unchecked")
			List fileList = upload.parseRequest(request);
			Iterator it = fileList.iterator();
			List tempFileList = new ArrayList();
			while (it.hasNext()) {
				FileItem item = it.next();
				if (!item.isFormField()) {
					String fileName = item.getName();
					if (fileName != null)
				     {
				      File file = new File(fileName);
				      item.write(file);
				      MultipartEntity multipartEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE, null,Charset.forName("UTF-8")); 
				      FileBody fileBody = new FileBody(file); 
				      multipartEntity.addPart(fileName, fileBody);  
				      post.setEntity(multipartEntity);
				      tempFileList.add(file);
				     }
				}	
			}
			HttpResponse response = client.execute(post);
			json = TicketUtils.getResponseBodyAsString(response);
			//delete temp files
			for(File file : tempFileList){
				file.delete();
			}
		} catch (Exception e) {
			log.error(e);
			json = JsonUtil.getJsonString(Const.ERROR_MESSAGE, EM.TICKET_EXCEPTION);
		}finally{
			client.getConnectionManager().shutdown();
		}
        return json;
    }

7、文件下载

 public void downloadAttachment(HttpServletRequest request, HttpServletResponse response, @PathVariable("fileId") Integer fileId){
		HttpClient client = TicketUtils.getClient(); 
		try {
	        HttpGet get = new HttpGet(urlStr); 

	        ResponseHandler handler = new ResponseHandler() {  
                public byte[] handleResponse(HttpResponse response)  
                        throws ClientProtocolException, IOException {  
                    HttpEntity entity = response.getEntity();  
                    if (entity != null) {  
                        return EntityUtils.toByteArray(entity);  
                    } else {  
                        return null;  
                    }  
                }  
            };
            byte[] charts = client.execute(get, handler);

	        URL url = new URL(urlStr);
	        HttpURLConnection uc = (HttpURLConnection)url.openConnection();
	        response.reset();
			response.addHeader("Content-disposition",uc.getHeaderField("Content-disposition"));
			OutputStream output = new BufferedOutputStream(response.getOutputStream());
	        output.write(charts); 
	        output.flush();
	        output.close();  
	        get.releaseConnection();
		} catch (Exception e) {
			log.error(e);
		}finally{
			client.getConnectionManager().shutdown();
		}
    }