Java Socket connect() 方法

2025 年 3 月 25 日 | 阅读 3 分钟

connect(SocketAddress endpoint)

Java Socket 类的 connect() 方法用于将指定的套接字连接到服务器。

语法

参数

'endpoint' 参数代表 SocketAddress。

不适用

抛出

IOException - 如果连接过程中发生错误。

IllegalBlockingModeException - 如果此套接字有关联的通道且该通道处于非阻塞模式。

IllegalArgumentException - 如果指定的 endpoint 为 null，或者 SocketAddress 的子类不受此套接字支持。

示例 1

import java.io.IOException;
import java.net.*;
public class JavaSocketConnectExample1 {
    public static void main(String[] args) throws IOException {
      Socket socket = new Socket();
      InetAddress inetAddress=InetAddress.getByName("localhost");
      //the port should be greater or equal to 0, else it will throw an error
        int port=1085;
        //calling the constructor of the SocketAddress class
        SocketAddress socketAddress=new InetSocketAddress(inetAddress, port);
        //binding the  socket with the inetAddress and port number
        socket.bind(socketAddress);
        //connect() method connects the specified socket to the server
        socket.connect(socketAddress);
        System.out.println("Inet address: "+socket.getInetAddress());
        System.out.println("Port number: "+socket.getLocalPort());
    }
}

输出

Inet address: localhost/127.0.0.1
Port number: 1085

示例 2

import java.io.IOException;
import java.net.*;
public class JavaSocketConnectExample2 {
    public static void main(String[] args) throws IOException {
      Socket socket = new Socket();
      InetAddress inetAddress=InetAddress.getByName("localhost");
      //the port should be greater or equal to 0, else it will throw an error
        //passing negative port number
        int port=-1085;
        //calling the constructor of the SocketAddress class
        SocketAddress socketAddress=new InetSocketAddress(inetAddress, port);
        //binding the  socket with the inetAddress and port number
        socket.bind(socketAddress);
        //connect() method connects the specified socket to the server
        socket.connect(socketAddress);
        System.out.println("Inet address: "+socket.getInetAddress());
        System.out.println("Port number: "+socket.getLocalPort());
    }
}

输出

Exception in thread "main" java.lang.IllegalArgumentException: port out of range:-1085
	at java.net.InetSocketAddress.checkPort(InetSocketAddress.java:143)
	at java.net.InetSocketAddress.(InetSocketAddress.java:188)
	at com.tpointtech.JavaSocketConnectExample2.main(JavaSocketConnectExample2.java:13)

示例 3

import java.io.IOException;
import java.net.*;
public class JavaSocketConnectExample3 {
    public static void main(String[] args) throws IOException {
      Socket socket = new Socket();
        //passing null argument in the SocketAddress
        SocketAddress socketAddress=null;
        //binding the  socket with the inetAddress and port number
        socket.bind(socketAddress);
        //connect() method connects the specified socket to the server
        socket.connect(socketAddress);
        System.out.println("Inet address: "+socket.getInetAddress());
        System.out.println("Port number: "+socket.getLocalPort());
    }
}

输出

Exception in thread "main" java.lang.IllegalArgumentException: connect: The address can't be null
	at java.net.Socket.connect(Socket.java:560)
	at java.net.Socket.connect(Socket.java:538)
	at com.tpointtech.JavaSocketConnectExample3.main(JavaSocketConnectExample3.java:13)

connect(SocketAddress endpoint, int timeout)

Java Socket 类的 connect() 方法使用给定的超时值将此套接字连接到服务器。零超时表示无限超时。

语法

参数

endpoint - 它代表 SocketAddress。

timeout - 它代表要使用的超时值（以毫秒为单位）。

不适用

抛出

IOException - 如果连接过程中发生错误。

SocketTimeoutException - 如果在连接之前超时。

IllegalBlockingModeException - 如果此套接字有关联的通道且该通道处于非阻塞模式。

IllegalArgumentException - 如果 endpoint 为 null，或者 SocketAddress 的子类不受此套接字支持。

示例 1

import java.io.IOException;
import java.net.*;
public class JavaSocketConnectExample4 {
    public static void main(String[] args) throws IOException {
      Socket socket = new Socket();
      InetAddress inetAddress=InetAddress.getByName(null);
      //the port should be greater or equal to 0, else it will throw an error
        //passing negative port number
        int port=1085;
        //calling the constructor of the SocketAddress class
        SocketAddress socketAddress=new InetSocketAddress(inetAddress, port);
        //binding the  socket with the inetAddress and port number
        socket.bind(socketAddress);
        int timeout=1;
        //connect() method connects this socket to the server with the given timeout value.
        socket.connect(socketAddress,timeout);
        System.out.println("Inet address: "+socket.getInetAddress());
        System.out.println("Port number: "+socket.getLocalPort());
    }
}

输出

Inet address: localhost/127.0.0.1
Port number: 1085

示例 2

import java.io.IOException;
import java.net.*;
public class JavaSocketConnectExample5 {
    public static void main(String[] args) throws IOException {
      Socket socket = new Socket();
      InetAddress inetAddress=InetAddress.getByName(null);
      //the port should be greater or equal to 0, else it will throw an error
        //passing negative port number
        int port=1085;
        //calling the constructor of the SocketAddress class
        SocketAddress socketAddress=new InetSocketAddress(inetAddress, port);
        //binding the  socket with the inetAddress and port number
        socket.bind(socketAddress);
        //The timeout should be greater or equal to 0, else it will throw an exception
        int timeout=-10;
        //connect() method connects this socket to the server with the given timeout value.
        socket.connect(socketAddress,timeout);
        System.out.println("Inet address: "+socket.getInetAddress());
        System.out.println("Port number: "+socket.getLocalPort());
    }
}

输出

Exception in thread "main" java.lang.IllegalArgumentException: connect: timeout can't be negative
	at java.net.Socket.connect(Socket.java:563)
	at com.tpointtech.JavaSocketConnectExample5.main(JavaSocketConnectExample5.java:19)

下一主题Java Socket 类

Java Socket connect() 方法

connect(SocketAddress endpoint)

语法

参数

返回

抛出

示例 1

示例 2

示例 3

connect(SocketAddress endpoint, int timeout)

语法

参数

返回

抛出

示例 1

示例 2

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Java Socket connect() 方法

connect(SocketAddress endpoint)

语法

参数

返回

抛出

示例 1

示例 2

示例 3

connect(SocketAddress endpoint, int timeout)

语法

参数

返回

抛出

示例 1

示例 2

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