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;标签：原生,http,String,import,connection,new,java,null From： https://blog.51cto.com/u_11334685/5740089
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();
}
}
}