详解Java发送HTTP请求

import java.net.HttpURLConnection;
import java.net.URI;
 
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
 
 
import com.fasterxml.jackson.databind.ObjectMapper;

 <dependency>
			<groupId>org.apache.httpcomponents</groupId>
			<artifactId>httpcore</artifactId>
			<version>4.4.8</version>
		</dependency>
		<dependency>
			<groupId>org.apache.httpcomponents</groupId>
			<artifactId>httpclient</artifactId>
			<version>4.5.3</version>
		</dependency>

public static String getHttpData(String host, String servUri, String reString) throws Exception {
		StringBuffer sb = new StringBuffer();
		sb.append("getHttpData:host:" + host + ",servUri:" + servUri + ",reString:" + reString);
		String strResp = null;
		try {
			URI uri = new URIBuilder().setScheme("http").setHost(host).setPath(servUri)
					.setParameter("strInfo", reString).build();
			HttpGet httpGet = new HttpGet(uri);
			CloseableHttpClient client3 = HttpClients.createDefault();
			HttpResponse resp;
			resp = client3.execute(httpGet);
			if (resp.getStatusLine().getStatusCode() == HttpURLConnection.HTTP_OK) {
				strResp = EntityUtils.toString(resp.getEntity());
				logger.info("the return result:{}", strResp);
			} else {
				logger.info("Error Response:", resp.getStatusLine().toString());
				throw new CommonBusinessException(CommonConstants.TASK_RELEASE_WCF,
						CommonConstants.TASK_RELEASE_WCF_DESC);
			}
		} catch (Exception e) {
			logger.error(sb.toString() + ":" + e.getMessage(), e.getCause());
			throw new CommonBusinessException(CommonConstants.TASK_RELEASE_WCF, CommonConstants.TASK_RELEASE_WCF_DESC);
		}
		return strResp;
	}
 

public static String doPostData(String url, String json) throws Exception {
		DefaultHttpClient client = new DefaultHttpClient();
		HttpPost post = new HttpPost(url);
		String result = "";
		HttpResponse res = null;
		try {
			StringEntity s = new StringEntity(json.toString(), "UTF-8");
			s.setContentType("application/json");
			post.setHeader("Accept", "application/json");
			post.setHeader("Content-type", "application/json; charset=utf-8");
			post.setEntity(s);
			res = client.execute(post);
			if (res.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
				result = EntityUtils.toString(res.getEntity());
				return HttpStatus.SC_OK + "";
			}
		} catch (Exception e) {
			if(res == null) {
				return "HttpResponse 为 null!";
			}
			throw new RuntimeException(e);
		}
		if(res == null || res.getStatusLine() == null) {
			return "无响应";
		}
		return res.getStatusLine().getStatusCode() + "";
	}

@Test
  public void test12() throws Exception {
    String HOST = "http://eipwcf.aspirecn.com/SvcEF/Service1.svc/WCF_EF_MSA_GetDataInfo_P";
    HttpClient client = new HttpClient();
    JSONObject json = new JSONObject();
    json.put("msgId", msgId);
    String reslut=client.doPostData(HOST, json);
  }
 

public static String doHttpPostData(String url, TaskReleaseApprovalModel tram)
			throws Exception {
		StringBuffer sb = new StringBuffer();
		sb.append("doHttpPostData:url:" + url + ",tram:" + tram.toString() + ",contentType:" + contentType);
		logger.info(sb.toString());
		String tmpString = "";
		HttpPost request = new HttpPost(url);
		request.setHeader("Accept", "application/json");
		request.setHeader("Content-type", "application/json");
		ObjectMapper mapper = new ObjectMapper();
		String jsonString;
		try {
			jsonString = mapper.writeValueAsString(tram);
			StringEntity entity = new StringEntity(jsonString, "UTF-8");
			request.setEntity(entity);
			CloseableHttpClient client = HttpClients.createDefault();
			HttpResponse response = client.execute(request);
			if (response.getStatusLine().getStatusCode() == HttpURLConnection.HTTP_OK) {
				tmpString = EntityUtils.toString(response.getEntity());
				logger.info("the post result:tmpString:{}", tmpString);
			} else {
				logger.info("the post failure:tmpString:", tmpString);
				throw new CommonBusinessException(CommonConstants.TASK_RELEASE_WCF,
						CommonConstants.TASK_RELEASE_WCF_DESC);
			}
		} catch (Exception e) {
			logger.error(sb.toString() + ":" + e.getMessage(), e.getCause());
			throw new CommonBusinessException(CommonConstants.TASK_RELEASE_POSTWCF,
					CommonConstants.TASK_RELEASE_POSTWCF_DESC);
		}
		return tmpString;
	}