????????程序员日常工作中，发送http请求特别常见。本文以Java为例，总结发送http请求的多种方式。
????????1. HttpURLConnection ????????使用JDK原生提供的net，无需其他jar包，代码如下：
import com.alibaba.fastjson.JSON; import java.io.BufferedReader; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.URL; import java.util.HashMap; import java.util.Map; public class HttpTest1 { public static void main(String[] args) { HttpURLConnection con = null; BufferedReader buffer = null; StringBuffer resultBuffer = null; try { URL url = new URL("http://10.30.10.151:8012/gateway.do"); //得到连接对象 con = (HttpURLConnection) url.openConnection(); //设置请求类型 con.setRequestMethod("POST"); //设置Content-Type，此处根据实际情况确定 con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); //允许写出 con.setDoOutput(true); //允许读入 con.setDoInput(true); //不使用缓存 con.setUseCaches(false); OutputStream os = con.getOutputStream(); Map paraMap = new HashMap(); paraMap.put("type", "wx"); paraMap.put("mchid", "10101"); //组装入参 os.write(("consumerAppId=test&serviceName=queryMerchantService¶ms=" + JSON.toJSONString(paraMap)).getBytes()); //得到响应码 int responseCode = con.getResponseCode(); if (responseCode == HttpURLConnection.HTTP_OK) { //得到响应流 InputStream inputStream = con.getInputStream(); //将响应流转换成字符串 resultBuffer = new StringBuffer(); String line; buffer = new BufferedReader(new InputStreamReader(inputStream, "GBK")); while ((line = buffer.readLine()) != null) { resultBuffer.append(line); } System.out.println("result:" + resultBuffer.toString()); } } catch (Exception e) { e.printStackTrace(); } } }????????
????????2. HttpClient
????????需要用到commons-httpclient-3.1.jar，maven依赖如下：
<dependency> <groupId>commons-httpclient</groupId> <artifactId>commons-httpclient</artifactId> <version>3.1</version> </dependency>??????? 代码如下：
import com.alibaba.fastjson.JSON; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.methods.PostMethod; import java.io.IOException; import java.util.HashMap; import java.util.Map; public class HttpTest2 { public static void main(String[] args) { HttpClient httpClient = new HttpClient(); PostMethod postMethod = new PostMethod("http://10.30.10.151:8012/gateway.do"); postMethod.addRequestHeader("accept", "*/*"); //设置Content-Type，此处根据实际情况确定 postMethod.addRequestHeader("Content-Type", "application/x-www-form-urlencoded"); //必须设置下面这个Header //添加请求参数 Map paraMap = new HashMap(); paraMap.put("type", "wx"); paraMap.put("mchid", "10101"); postMethod.addParameter("consumerAppId", "test"); postMethod.addParameter("serviceName", "queryMerchantService"); postMethod.addParameter("params", JSON.toJSONString(paraMap)); String result = ""; try { int code = httpClient.executeMethod(postMethod); if (code == 200){ result = postMethod.getResponseBodyAsString(); System.out.println("result:" + result); } } catch (IOException e) { e.printStackTrace(); } } }????????3. CloseableHttpClient ????????需要用到httpclient-4.5.6.jar，maven依赖如下：?
<dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.5.6</version> </dependency>??????? 代码如下：
import com.alibaba.fastjson.JSON; import org.apache.http.Consts; import org.apache.http.HttpEntity; import org.apache.http.NameValuePair; import org.apache.http.client.config.RequestConfig; 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; import org.apache.http.util.EntityUtils; import java.io.IOException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class HttpTest3 { public static void main(String[] args) { int timeout = 120000; CloseableHttpClient httpClient = HttpClients.createDefault(); RequestConfig defaultRequestConfig = RequestConfig.custom().setConnectTimeout(timeout) .setConnectionRequestTimeout(timeout).setSocketTimeout(timeout).build(); HttpPost httpPost = null; List<NameValuePair> nvps = null; CloseableHttpResponse responses = null;// 命名冲突，换一个名字，response HttpEntity resEntity = null; String result; try { httpPost = new HttpPost("http://10.30.10.151:8012/gateway.do"); httpPost.setConfig(defaultRequestConfig); Map paraMap = new HashMap(); paraMap.put("type", "wx"); paraMap.put("mchid", "10101"); nvps = new ArrayList<NameValuePair>(); nvps.add(new BasicNameValuePair("consumerAppId", "test")); nvps.add(new BasicNameValuePair("serviceName", "queryMerchantService")); nvps.add(new BasicNameValuePair("params", JSON.toJSONString(paraMap))); httpPost.setEntity(new UrlEncodedFormEntity(nvps, Consts.UTF_8)); responses = httpClient.execute(httpPost); resEntity = responses.getEntity(); result = EntityUtils.toString(resEntity, Consts.UTF_8); EntityUtils.consume(resEntity); System.out.println("result:" + result); } catch (Exception e) { e.printStackTrace(); } finally { try { responses.close(); httpClient.close(); } catch (IOException e) { e.printStackTrace(); } } } }?????????4. okhttp ????????需要用到okhttp-3.10.0.jar，maven依赖如下：
<dependency> <groupId>com.squareup.okhttp3</groupId> <artifactId>okhttp</artifactId> <version>3.10.0</version> </dependency>????????代码如下：
import com.alibaba.fastjson.JSON; import okhttp3.*; import java.io.IOException; import java.util.HashMap; import java.util.Map; public class HttpTest4 { public static void main(String[] args) throws IOException { String url = "http://10.30.10.151:8012/gateway.do"; OkHttpClient client = new OkHttpClient(); Map paraMap = new HashMap(); paraMap.put("yybh", "1231231"); RequestBody requestBody = new MultipartBody.Builder() .addFormDataPart("consumerAppId", "tst") .addFormDataPart("serviceName", "queryCipher") .addFormDataPart("params", JSON.toJSONString(paraMap)) .build(); Request request = new Request.Builder() .url(url) .post(requestBody) .addHeader("Content-Type", "application/x-www-form-urlencoded") .build(); Response response = client .newCall(request) .execute(); if (response.isSuccessful()) { System.out.println("result:" + response.body().string()); } else { throw new IOException("Unexpected code " + response); } } }?????????5. Socket ????????使用JDK原生提供的net，无需其他jar包 ????????此处参考：https://·/hehongtao/p/5276425.html ????????代码如下：
import com.alibaba.fastjson.JSON; import java.io.IOException; import java.io.InputStream; import java.io.OutputStreamWriter; import java.net.Socket; import java.net.URLEncoder; import java.net.UnknownHostException; import java.util.ArrayList; import java.util.HashMap; import java.util.Map; public class HttpTest6 { private static String encoding = "utf-8"; public static void main(String[] args) { try { Map paraMap = new HashMap(); paraMap.put("yybh", "12312311"); String data = URLEncoder.encode("consumerAppId", "utf-8") + "=" + URLEncoder.encode("test", "utf-8") + "&" + URLEncoder.encode("serviceName", "utf-8") + "=" + URLEncoder.encode("queryCipher", "utf-8") + "&" + URLEncoder.encode("params", "utf-8") + "=" + URLEncoder.encode(JSON.toJSONString(paraMap), "utf-8"); Socket s = new Socket("10.30.10.151", 8012); OutputStreamWriter osw = new OutputStreamWriter(s.getOutputStream()); StringBuffer sb = new StringBuffer(); sb.append("POST /gateway.do HTTP/1.1\r\n"); sb.append("Host: 10.30.10.151:8012\r\n"); sb.append("Content-Length: " + data.length() + "\r\n"); sb.append("Content-Type: application/x-www-form-urlencoded\r\n"); //注，这里很关键。这里一定要一个回车换行，表示消息头完，不然服务器会等待 sb.append("\r\n"); osw.write(sb.toString()); osw.write(data); osw.write("\r\n"); osw.flush(); //--输出服务器传回的消息的头信息 InputStream is = s.getInputStream(); String line = null; int contentLength = 0;//服务器发送回来的消息长度 // 读取所有服务器发送过来的请求参数头部信息 do { line = readLine(is, 0); //如果有Content-Length消息头时取出 if (line.startsWith("Content-Length")) { contentLength = Integer.parseInt(line.split(":")[1].trim()); } //打印请求部信息 System.out.print(line); //如果遇到了一个单独的回车换行，则表示请求头结束 } while (!line.equals("\r\n")); //--输消息的体 System.out.print(readLine(is, contentLength)); //关闭流 is.close(); } catch (UnknownHostException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /* * 这里我们自己模拟读取一行，因为如果使用API中的BufferedReader时，它是读取到一个回车换行后 * 才返回，否则如果没有读取，则一直阻塞，直接服务器超时自动关闭为止，如果此时还使用BufferedReader * 来读时，因为读到最后一行时，最后一行后不会有回车换行符，所以就会等待。如果使用服务器发送回来的 * 消息头里的Content-Length来截取消息体，这样就不会阻塞 * * contentLe 参数 如果为0时，表示读头，读时我们还是一行一行的返回；如果不为0，表示读消息体， * 时我们根据消息体的长度来读完消息体后，客户端自动关闭流，这样不用先到服务器超时来关闭。 */ private static String readLine(InputStream is, int contentLe) throws IOException { ArrayList lineByteList = new ArrayList(); byte readByte; int total = 0; if (contentLe != 0) { do { readByte = (byte) is.read(); lineByteList.add(Byte.valueOf(readByte)); total++; } while (total < contentLe);//消息体读还未读完 } else { do { readByte = (byte) is.read(); lineByteList.add(Byte.valueOf(readByte)); } while (readByte != 10); } byte[] tmpByteArr = new byte[lineByteList.size()]; for (int i = 0; i < lineByteList.size(); i++) { tmpByteArr[i] = ((Byte) lineByteList.get(i)).byteValue(); } lineByteList.clear(); return new String(tmpByteArr, encoding); } }????????6. RestTemplate ????????RestTemplate 是由Spring提供的一个HTTP请求工具。比传统的Apache和HttpCLient便捷许多，能够大大提高客户端的编写效率。代码如下：
import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.http.client.ClientHttpRequestFactory; import org.springframework.http.client.SimpleClientHttpRequestFactory; import org.springframework.web.client.RestTemplate; @Configuration public class RestTemplateConfig { @Bean public RestTemplate restTemplate(ClientHttpRequestFactory factory){ return new RestTemplate(factory); } @Bean public ClientHttpRequestFactory simpleClientHttpRequestFactory(){ SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory(); factory.setConnectTimeout(15000); factory.setReadTimeout(5000); return factory; } } @Autowired RestTemplate restTemplate; @Test public void postTest() throws Exception { MultiValueMap<String, String> requestEntity = new LinkedMultiValueMap<>(); Map paraMap = new HashMap(); paraMap.put("type", "wx"); paraMap.put("mchid", "10101"); requestEntity.add("consumerAppId", "test"); requestEntity.add("serviceName", "queryMerchant"); requestEntity.add("params", JSON.toJSONString(paraMap)); RestTemplate restTemplate = new RestTemplate(); System.out.println(restTemplate.postForObject("http://10.30.10.151:8012/gateway.do", requestEntity, String.class)); }
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标签： #java发送http请求
