类继承图

1.接口 2.抽象类 3.实现类

接口SocketImpl

/*** The abstract class {@code SocketImpl} is a common superclass* of all classes that actually implement sockets. It is used to* create both client and server sockets.* <p>* A "plain" socket implements these methods exactly as* described, without attempting to go through a firewall or proxy.** @author  unascribed* @since   JDK1.0*/public abstract class SocketImpl implements SocketOptions {/*** The actual Socket object.*/Socket socket = null; //客户端套接字ServerSocket serverSocket = null; //服务器端套接字/*** The file descriptor object for this socket.*/protected FileDescriptor fd; //套接字的文件描述符/*** The IP address of the remote end of this socket.*/protected InetAddress address; //以下是ip地址和端口/*** The port number on the remote host to which this socket is connected.*/protected int port;/*** The local port number to which this socket is connected.*/protected int localport;复制代码

服务器端套接字类

包含了套接字实现类

publicclass ServerSocket implements java.io.Closeable {/*** Various states of this socket.*/private boolean created = false;private boolean bound = false;private boolean closed = false;private Object closeLock = new Object();/*** The implementation of this Socket.*/private SocketImpl impl; //套接字实现类复制代码

客户端套接字类

也包含了套接字实现类

publicclass Socket implements java.io.Closeable {/*** Various states of this socket.*/private boolean created = false;private boolean bound = false;private boolean connected = false;private boolean closed = false;private Object closeLock = new Object();private boolean shutIn = false;private boolean shutOut = false;/*** The implementation of this Socket.*/SocketImpl impl; //套接字实现类/*** Are we using an older SocketImpl?*/private boolean oldImpl = false;复制代码

套接字实现类-简单套接字实现类

class PlainSocketImpl extends AbstractPlainSocketImpl{private AbstractPlainSocketImpl impl;复制代码