HTTP连接池

@Service
public class HttpClientService {

	@Autowired
	private CloseableHttpClient httpClient;
	
	@Autowired
	private RequestConfig requestConfig;
	
	/**
	 * 执行GET请求
	 * 
	 * @param url
	 * @return
	 * @throws IOException
	 * @throws ClientProtocolException
	 */
	public String doGet(String url) throws ClientProtocolException, IOException {
		// 创建http GET请求
		HttpGet httpGet = new HttpGet(url);
		httpGet.setConfig(this.requestConfig);

		CloseableHttpResponse response = null;
		try {
			// 执行请求
			response = httpClient.execute(httpGet);
			// 判断返回状态是否为200
			if (response.getStatusLine().getStatusCode() == 200) {
				return EntityUtils.toString(response.getEntity(), "UTF-8");
			}
		} finally {
			if (response != null) {
				response.close();
			}
		}
		return null;
	}
	
	/**
	 * 带有参数的GET请求
	 * 
	 * @param url
	 * @param params
	 * @return
	 * @throws URISyntaxException
	 * @throws IOException
	 * @throws ClientProtocolException
	 */
	public String doGet(String url, Map params)
			throws ClientProtocolException, IOException, URISyntaxException {
		URIBuilder uriBuilder = new URIBuilder(url);
		for (String key : params.keySet()) {
			uriBuilder.addParameter(key, params.get(key));
		}
		return this.doGet(uriBuilder.build().toString());
	}
	
	/**
	 * 执行POST请求
	 * 
	 * @param url
	 * @param params
	 * @return
	 * @throws IOException
	 */
	public HttpResult doPost(String url, Map params) throws IOException {
		// 创建http POST请求
		HttpPost httpPost = new HttpPost(url);
		httpPost.setConfig(this.requestConfig);
		if (params != null) {
			// 设置2个post参数，一个是scope、一个是q
			List parameters = new ArrayList();
			for (String key : params.keySet()) {
				parameters.add(new BasicNameValuePair(key, params.get(key)));
			}
			// 构造一个form表单式的实体
			UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(parameters, "UTF-8");
			// 将请求实体设置到httpPost对象中
			httpPost.setEntity(formEntity);
		}

		CloseableHttpResponse response = null;
		try {
			// 执行请求
			response = httpClient.execute(httpPost);
			return new HttpResult(response.getStatusLine().getStatusCode(),
					EntityUtils.toString(response.getEntity(), "UTF-8"));
		} finally {
			if (response != null) {
				response.close();
			}
		}
	}
	
	/**
	 * 执行POST请求
	 * 
	 * @param url
	 * @return
	 * @throws IOException
	 */
	public HttpResult doPost(String url) throws IOException {
		return this.doPost(url, null);
	}
	
	/**
	 * 提交json数据
	 * 
	 * @param url
	 * @param json
	 * @return
	 * @throws ClientProtocolException
	 * @throws IOException
	 */
	public HttpResult doPostJson(String url, String json) throws ClientProtocolException, IOException {
		// 创建http POST请求
		HttpPost httpPost = new HttpPost(url);
		httpPost.setConfig(this.requestConfig);

		if (json != null) {
			// 构造一个form表单式的实体
			StringEntity stringEntity = new StringEntity(json, ContentType.APPLICATION_JSON);
			// 将请求实体设置到httpPost对象中
			httpPost.setEntity(stringEntity);
		}

		CloseableHttpResponse response = null;
		try {
			// 执行请求
			response = this.httpClient.execute(httpPost);
			return new HttpResult(response.getStatusLine().getStatusCode(),
					EntityUtils.toString(response.getEntity(), "UTF-8"));
		} finally {
			if (response != null) {
				response.close();
			}
		}
	}