根据技术选型总结常见的三种方式发送http请求，本问介绍jdk原生方式，其他两种如下链接
Springboot整合RestTemplate发送http请求
使用JDK原生提供的net包下的HttpURLConnection、URLConnection、Socket三个类都可实现，无需其他jar包
1、HttpURLConnection类实现
HttpURLConnection是URLConnection的子类，提供更多的方法，使用更方便。
比较原始的一种调用做法，这里把get请求和post请求都统一放在一个方法里面。
请求过程
GET: 1、创建远程连接 2、设置连接方式（get、post、put。。。） 3、设置连接超时时间 4、设置响应读取时间 5、发起请求 6、获取请求数据 7、关闭连接 POST: 1、创建远程连接 2、设置连接方式（get、post、put。。。） 3、设置连接超时时间 4、设置响应读取时间 5、当向远程服务器传送数据/写数据时，需要设置为true（setDoOutput） 6、当前向远程服务读取数据时，设置为true，该参数可有可无（setDoInput） 7、设置传入参数的格式:（setRequestProperty） 8、设置鉴权信息：Authorization:（setRequestProperty） 9、设置参数 10、发起请求 11、获取请求数据 12、关闭连接
代码
package com.riemann.springbootdemo.util.common.httpConnectionUtil; import org.springframework.lang.Nullable; import java.io.*; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import java.net.URLConnection; public class HttpURLConnectionUtil { /** * Http get请求 * @param httpUrl 连接 * @return 响应数据 */ public static String doGet(String httpUrl){ //链接 HttpURLConnection connection = null; InputStream is = null; BufferedReader br = null; StringBuffer result = new StringBuffer(); try { //创建连接 URL url = new URL(httpUrl); connection = (HttpURLConnection) url.openConnection(); //设置请求方式 connection.setRequestMethod("GET"); //设置连接超时时间 connection.setReadTimeout(15000); //开始连接 connection.connect(); //获取响应数据 if (connection.getResponseCode() == 200) { //获取返回的数据 is = connection.getInputStream(); if (null != is) { br = new BufferedReader(new InputStreamReader(is, "UTF-8")); String temp = null; while (null != (temp = br.readLine())) { result.append(temp); } } } } catch (IOException e) { e.printStackTrace(); } finally { if (null != br) { try { br.close(); } catch (IOException e) { e.printStackTrace(); } } if (null != is) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } //关闭远程连接 connection.disconnect(); } return result.toString(); } /** * Http post请求 * @param httpUrl 连接 * @param param 参数 * @return */ public static String doPost(String httpUrl, @Nullable String param) { StringBuffer result = new StringBuffer(); //连接 HttpURLConnection connection = null; OutputStream os = null; InputStream is = null; BufferedReader br = null; try { //创建连接对象 URL url = new URL(httpUrl); //创建连接 connection = (HttpURLConnection) url.openConnection(); //设置请求方法 connection.setRequestMethod("POST"); //设置连接超时时间 connection.setConnectTimeout(15000); //设置读取超时时间 connection.setReadTimeout(15000); //DoOutput设置是否向httpUrlConnection输出，DoInput设置是否从httpUrlConnection读入，此外发送post请求必须设置这两个 //设置是否可读取 connection.setDoOutput(true); connection.setDoInput(true); //设置通用的请求属性 connection.setRequestProperty("accept", "*/*"); connection.setRequestProperty("connection", "Keep-Alive"); connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"); connection.setRequestProperty("Content-Type", "application/json;charset=utf-8"); //拼装参数 if (null != param && param.equals("")) { //设置参数 os = connection.getOutputStream(); //拼装参数 os.write(param.getBytes("UTF-8")); } //设置权限 //设置请求头等 //开启连接 //connection.connect(); //读取响应 if (connection.getResponseCode() == 200) { is = connection.getInputStream(); if (null != is) { br = new BufferedReader(new InputStreamReader(is, "GBK")); String temp = null; while (null != (temp = br.readLine())) { result.append(temp); result.append("\r\n"); } } } } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { //关闭连接 if(br!=null){ try { br.close(); } catch (IOException e) { e.printStackTrace(); } } if(os!=null){ try { os.close(); } catch (IOException e) { e.printStackTrace(); } } if(is!=null){ try { is.close(); } catch (IOException e) { e.printStackTrace(); } } //关闭连接 connection.disconnect(); } return result.toString(); } public static void main(String[] args) { String message = doPost("https://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", ""); System.out.println(message); } }
2、URLConnection类实现
package uRLConnection; import java.io.BufferedReader; import java.io.InputStream; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.URL; import java.net.URLConnection; public class URLConnectionHelper { public static String sendRequest(String urlParam) { URLConnection con = null; BufferedReader buffer = null; StringBuffer resultBuffer = null; try { URL url = new URL(urlParam); con = url.openConnection(); //设置请求需要返回的数据类型和字符集类型 con.setRequestProperty("Content-Type", "application/json;charset=GBK"); //允许写出 con.setDoOutput(true); //允许读入 con.setDoInput(true); //不使用缓存 con.setUseCaches(false); //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); } return resultBuffer.toString(); }catch(Exception e) { e.printStackTrace(); } return ""; } public static void main(String[] args) { String url ="http://int.dpool.sina.com.cn/iplookup/iplookup.php?ip=120.79.75.96"; System.out.println(sendRequest(url)); } }
3、Socket类实现
package socket; import java.io.BufferedInputStream; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.net.Socket; import java.net.URLEncoder; import javax.net.ssl.SSLSocket; import javax.net.ssl.SSLSocketFactory; public class SocketForHttpTest { private int port; private String host; private Socket socket; private BufferedReader bufferedReader; private BufferedWriter bufferedWriter; public SocketForHttpTest(String host,int port) throws Exception{ this.host = host; this.port = port; /** * http协议 */ // socket = new Socket(this.host, this.port); /** * https协议 */ socket = (SSLSocket)((SSLSocketFactory)SSLSocketFactory.getDefault()).createSocket(this.host, this.port); } public void sendGet() throws IOException{ //String requestUrlPath = "/z69183787/article/details/17580325"; String requestUrlPath = "/"; OutputStreamWriter streamWriter = new OutputStreamWriter(socket.getOutputStream()); bufferedWriter = new BufferedWriter(streamWriter); bufferedWriter.write("GET " + requestUrlPath + " HTTP/1.1\r\n"); bufferedWriter.write("Host: " + this.host + "\r\n"); bufferedWriter.write("\r\n"); bufferedWriter.flush(); BufferedInputStream streamReader = new BufferedInputStream(socket.getInputStream()); bufferedReader = new BufferedReader(new InputStreamReader(streamReader, "utf-8")); String line = null; while((line = bufferedReader.readLine())!= null){ System.out.println(line); } bufferedReader.close(); bufferedWriter.close(); socket.close(); } public void sendPost() throws IOException{ String path = "/"; String data = URLEncoder.encode("name", "utf-8") + "=" + URLEncoder.encode("张三", "utf-8") + "&" + URLEncoder.encode("age", "utf-8") + "=" + URLEncoder.encode("32", "utf-8"); // String data = "name=zhigang_jia"; System.out.println(">>>>>>>>>>>>>>>>>>>>>"+data); OutputStreamWriter streamWriter = new OutputStreamWriter(socket.getOutputStream(), "utf-8"); bufferedWriter = new BufferedWriter(streamWriter); bufferedWriter.write("POST " + path + " HTTP/1.1\r\n"); bufferedWriter.write("Host: " + this.host + "\r\n"); bufferedWriter.write("Content-Length: " + data.length() + "\r\n"); bufferedWriter.write("Content-Type: application/x-www-form-urlencoded\r\n"); bufferedWriter.write("\r\n"); bufferedWriter.write(data); bufferedWriter.write("\r\n"); bufferedWriter.flush(); BufferedInputStream streamReader = new BufferedInputStream(socket.getInputStream()); bufferedReader = new BufferedReader(new InputStreamReader(streamReader, "utf-8")); String line = null; while((line = bufferedReader.readLine())!= null) { System.out.println(line); } bufferedReader.close(); bufferedWriter.close(); socket.close(); } public static void main(String[] args) throws Exception { /** * http协议测试 */ //SocketForHttpTest forHttpTest = new SocketForHttpTest("www.baidu.com", 80); /** * https协议测试 */ SocketForHttpTest forHttpTest = new SocketForHttpTest("www.baidu.com", 443); try { forHttpTest.sendGet(); // forHttpTest.sendPost(); } catch (IOException e) { e.printStackTrace(); } } }
