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原文链接：https://blog.csdn.net/qq_16055765/article/details/83342069

项目中用到 Java 的 http 访问，Java 原生 HttpURLConnection 请求实现记录如下：

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import java.io.*;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;

  public class HttpURLConnectionUtil {
    /**
     * http get请求
     * @param httpUrl 链接
     * @return 响应数据
     */
      public static String httpGet(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.setConnectTimeout(15000);
            //设置读取超时时间
            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(is!=null){
                    br=new BufferedReader(new InputStreamReader(is,"UTF-8"));
                    String temp = null;
                    while ((temp=br.readLine())!=null){
                        result.append(temp);
                    }
                }
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if(br!=null){
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(is!=null){
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            connection.disconnect();// 关闭远程连接
        }
        return result.toString();
      }

    /**
     * post请求
     * @param httpUrl 链接
     * @param param 参数
     * @return
     */
      public static String httpPost(String httpUrl, 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);
            //设置是否可读取
            connection.setDoOutput(true);
            //设置响应是否可读取
            connection.setDoInput(true);
            //设置参数类型
            connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            //拼装参数
            if(param!=null&&!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(is!=null){
                    br=new BufferedReader(new InputStreamReader(is,"UTF-8"));
                    String temp=null;
                    if((temp=br.readLine())!=null){
                        result.append(temp);
                    }
                }
            }
            //关闭连接
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            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[] str){
        /*String result=HttpURLConnectionUtil.hGet("http://localhost:8080/test");
        System.out.println(result);*/
        /*Map<String, Object> map=new HashMap<>();
        map.put("1","1");
        map.put("2","2");
        map.put("3","3");
        System.out.println(HttpURLConnectionUtil.getParamStr(map));*/
    }
  }