如何在 Java 中打开多个 TCP 连接

Question

I have to open plenty of TCP connections to a SIP server which is runnning on linux. I tried with one simple client program in Java, but I could not open even 350 connections from another linux server. I want to open ~ 50 thousand and above for a load/performance test.

Is there any way to overcome this? What are the limitations? Sorry if this is a silly question,I am a Beginner.

Thanks

client program

public class ConnectionTcp
{
static int noOfconnected;
Socket socket;
static int port=1000;
static Object obj=new Object();
static AtomicInteger atomicInteger;
public static void main(String[]args)
{
try{
ConnectionTcp con=new ConnectionTcp();
atomicInteger = new AtomicInteger();
Date date = new Date();
for(int i=0;i<50000;i++)
{
port+=i;    

con.sendmsg();
}
}
catch(Exception e)
{
System.out.println(e);
}
}
public  synchronized  void sendmsg(){
        try{
        Thread.sleep(100);  
        }
        catch(Exception e){
        System.out.println(e);
        }    
        Runnable r=new Runnable(){
            public void run(){
                try{
                    boolean check=true;
                    InetAddress ip=InetAddress.getByName("131.10.20.16");  
                    Socket socket=new Socket("131.10.20.17",5060,ip,port);              
                    System.out.println("conected is "+socket.isConnected()+"<----------with port----------->"+socket.getLocalPort());


                    OutputStream out =socket.getOutputStream();
                    InputStream in =socket.getInputStream();
                        String str = "keep alive";
                        byte[] array = str.getBytes();          
                    System.out.println("no of user connected with server is "+atomicInteger.incrementAndGet());
                    while(true){                    
                        try{
                            int i = in.read();
                            out.write(array);                           
                        }catch(Exception e){
                            System.out.println("exception"+e);
                            atomicInteger.decrementAndGet();
                            socket.close();
                            Date date = new Date();    
                             System.out.println("Ented Time  is "+date.toString());
                            break;
                        }
                    }
                }catch(Exception e1){   
                System.out.println("main exception"+e1);
                atomicInteger.decrementAndGet();
                }
            }
        };
        (new Thread(r,"tcp")).start();        
    }
}

Answer 1

您只能使用 1023 以上的端口。较低的数字是保留的。

Answer 2

It is a programming logic problem. Accessing the port value inside the run method is not meant, first thread gets port as 1000 and the next one as 1001. It can be succeeded incrementing the port value with incrementAndGet() to bind the port sequentially.

 public class ConnectionTcp
{
static AtomicInteger atomicInteger;
public static void main(String[]args)
{
ConnectionTcp con=new ConnectionTcp();
atomicInteger_=new AtomicInteger(1000);
for(int i=0;i<5000;i++)
{
con.sendmsg();
}
}
public  synchronized void sendmsg(){    
        Runnable r=new Runnable(){
            public void run(){
                try{                    
                    InetAddress ip=InetAddress.getByName("192.168.1.22");                   
                    int port = atomicInteger.incrementAndGet();                 
                    Socket socket=new Socket("131.10.20.17",5060,ip,port);                  
                    OutputStream out =socket.getOutputStream();
                    InputStream in =socket.getInputStream();
                        String str = "keep alive";
                        byte[] array = str.getBytes();                      
                    while(true){                    
                        try{
                            int i = in.read();
                            out.write(array);                           
                        }catch(Exception e){
                            System.out.println("exception"+e);                              
                            socket.close();                     
                            break;
                        }
                    }
                }catch(Exception e1){   
                System.out.println("main exception"+e1);                    
                }
            }
        };
        (new Thread(r,"tcp")).start();        
    }
}

Answer 3

You don't need to specify either the local IP address or the local port. The operating system will do that for you. If you run out of ports, so be it: all that means is that your test isn't realistic. No single actual client is going to exhaust the local port space. Don't test things that aren't part of the problem space.