socketchannel，SocketFactory、DefaultSocketFactory、ServerSocketFactory、DefaultServ

　　SocketFactory是一個抽象類（抽象類不能被實例化，但可以有構造函數）。

　　描述：This class creates sockets./此類用于創建sockets

public abstract class SocketFactory {private static SocketFactory theFactory;
　　//返回環境默認的socket工廠的副本。public static SocketFactory getDefault() {synchronized (SocketFactory.class) {if (theFactory == null) {theFactory = new DefaultSocketFactory();}}return theFactory;}
　　//創建一個無連接的socket(拋出SocketException("Unconnected sockets not implemented")異常)public Socket createSocket() throws IOException {UnsupportedOperationException localUnsupportedOperationException = new UnsupportedOperationException();SocketException localSocketException = new SocketException("Unconnected sockets not implemented");localSocketException.initCause(localUnsupportedOperationException);throw localSocketException;}//創建一個套接字并將其連接到指定地址的指定端口號。public abstract Socket createSocket(String host, int port) throws IOException, UnknownHostException;　//創建套接字并將其連接到指定遠程主機的指定遠程端口號。public abstract Socket createSocket(String host, int port, InetAddress localHost, int localPort)throws IOException, UnknownHostException;//創建一個套接字并將其連接到指定地址的指定端口號。public abstract Socket createSocket(InetAddress address, int port) throws IOException;//創建套接字并將其連接到指定遠程地址上的指定遠程端口。public abstract Socket createSocket(InetAddress address, int port, InetAddress localAdress,int localPort) throws IOException;
}

　　DefaultSocketFactory是SocketFactory的子類。socket創建的默認工廠類

class DefaultSocketFactory extends SocketFactory {public Socket createSocket() {return new Socket();}public Socket createSocket(String paramString, int paramInt) throws IOException, UnknownHostException {return new Socket(paramString, paramInt);}public Socket createSocket(InetAddress paramInetAddress, int paramInt) throws IOException {return new Socket(paramInetAddress, paramInt);}public Socket createSocket(String paramString, int paramInt1, InetAddress paramInetAddress, int paramInt2)throws IOException, UnknownHostException {return new Socket(paramString, paramInt1, paramInetAddress, paramInt2);}public Socket createSocket(InetAddress paramInetAddress1, int paramInt1, InetAddress paramInetAddress2,int paramInt2) throws IOException {return new Socket(paramInetAddress1, paramInt1, paramInetAddress2, paramInt2);}
}

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　　ServerSocketFactory是一個抽象類（抽象類不能被實例化，但可以有構造函數）。

　　描述：This class creates server sockets./此類用于創建服務器套間字

　

public abstract class ServerSocketFactory {private static ServerSocketFactory theFactory;//返回環境默認的socket工廠副本
    public static ServerSocketFactory getDefault() {synchronized (ServerSocketFactory.class) {if (theFactory == null) {theFactory = new DefaultServerSocketFactory();}}return theFactory;}//返回一個未綁定的服務器套間字
    public ServerSocket createServerSocket() throws IOException {throw new SocketException("Unbound server sockets not implemented");}//返回一個綁定到指定端口的服務器套間字
    public abstract ServerSocket createServerSocket(int port) throws IOException;//返回一個綁定到指定端口的服務器套間字，并指定backlog參數
    public abstract ServerSocket createServerSocket(int port, int backlog) throws IOException;//返回一個綁定到指定端口的服務間套間字，并指定backlog和ip地址
    public abstract ServerSocket createServerSocket(int port, int backlog, InetAddress adress)throws IOException;
}                

　　DefaultServerSocketFactory是ServerSocketFactory的子類。ServerSocket創建的默認工廠類。

class DefaultServerSocketFactory extends ServerSocketFactory {public ServerSocket createServerSocket() throws IOException {return new ServerSocket();}public ServerSocket createServerSocket(int paramInt) throws IOException {return new ServerSocket(paramInt);}public ServerSocket createServerSocket(int paramInt1, int paramInt2) throws IOException {return new ServerSocket(paramInt1, paramInt2);}public ServerSocket createServerSocket(int paramInt1, int paramInt2, InetAddress paramInetAddress)throws IOException {return new ServerSocket(paramInt1, paramInt2, paramInetAddress);}
}

　　簡單測試

class TestFactory extends SocketFactory {@Overridepublic Socket createSocket(String paramString, int paramInt) throws IOException, UnknownHostException {return null;}@Overridepublic Socket createSocket(String paramString, int paramInt1, InetAddress paramInetAddress, int paramInt2)throws IOException, UnknownHostException {return null;}@Overridepublic Socket createSocket(InetAddress paramInetAddress, int paramInt) throws IOException {return null;}@Overridepublic Socket createSocket(InetAddress paramInetAddress1, int paramInt1, InetAddress paramInetAddress2,int paramInt2) throws IOException {return null;}public static void main(String[] args) throws UnknownHostException, IOException {TestFactory factory = new TestFactory();Socket socket1 = factory.createSocket("host", 1);System.out.println(socket1 == null);SocketFactory factory1 =  SocketFactory.getDefault();Socket socket2 = factory.createSocket("host", 1);System.out.println(socket2 == null);}
}

返回結果：

socketchannel、true

false

　

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