Simple Java HTTP Client Code Snippet for KeepAliveTesting

KeepAliveTest.java

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.WritableByteChannel;

class KeepAliveTest {

    public static void main(String[] args) throws IOException {
        while(true) {
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            br.readLine();
            
            long start = System.currentTimeMillis();

            URL url = new URL("http://172.27.1.25:5007/device/event/inputkeyevent");
            System.out.println("makeHTTPUrlConnection - " +  url.toString());
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();      
            
            conn.setConnectTimeout(3000);
            conn.setReadTimeout(3000);
            conn.setDoInput(true);
            conn.setDoOutput(true);
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Content-Type","application/json");
            conn.setRequestProperty("Accept", "application/json");
            
            ByteBuffer byteBuf = ByteBuffer.wrap("{\"code\":3}".getBytes());
            
            try(WritableByteChannel channel = Channels.newChannel(conn.getOutputStream())) {
                System.out.println("Connect : " + (System.currentTimeMillis()-start) + "ms");
                channel.write(byteBuf);
                System.out.println("Request : " + (System.currentTimeMillis()-start) + "ms");
            } 
            
            String body = null;
            
            try (BufferedInputStream in = new BufferedInputStream(conn.getInputStream())) {
                
                System.out.println("Response : " + (System.currentTimeMillis()-start) + "ms");
                System.out.println(System.currentTimeMillis()-start + "ms");
                System.out.println("Status:"+conn.getResponseCode());
                
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                byte[] byteArr= new byte[1024*8];
                int length = 0;
                while ((length = in.read(byteArr)) != -1) {
                    out.write(byteArr, 0, length);
                }
                body = new String(out.toByteArray(),"UTF-8");
            } catch(IOException e){
                InputStream errorStream = conn.getErrorStream();
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                byte[] byteArr= new byte[1024*8];
                int length = 0;
                while ((length = errorStream.read(byteArr)) != -1) {
                    out.write(byteArr, 0, length);
                }
                body = new String(out.toByteArray(),"UTF-8");
                e.printStackTrace();
            }
            
            System.out.println(body);
            System.out.println("Total:" + (System.currentTimeMillis()-start) + "ms");
        }
    }
}