Java 网络编程API以及实例 阳光穿透心脏的1/2处 2022-06-15 06:42 180阅读 0赞 ## Java 网络编程 ## 网络编程是指编写运行在多个设备(计算机)的程序,这些设备都通过网络连接起来。 java.net包中J2SE的API包含有类和接口,它们提供低层次的通信细节。你可以直接使用这些类和接口,来专注于解决问题,而不用关注通信细节。 java.net包中提供了两种常见的网络协议的支持: * TCP: TCP是传输控制协议的缩写,它保障了两个应用程序之间的可靠通信。通常用于互联网协议,被称TCP / IP。 * UDP:UDP是用户数据报协议的缩写,一个无连接的协议。提供了应用程序之间要发送的数据的数据包。 本教程主要讲解以下两个主题。 * Socket 编程: 这是使用最广泛的网络概念,它已被解释地非常详细 * URL 处理: 这部分会在另外的篇幅里讲,点击这里更详细地了解在[Java语言中的URL处理][Java_URL]。 -------------------- ## Socket 编程 ## 套接字使用TCP提供了两台计算机之间的通信机制。 客户端程序创建一个套接字,并尝试连接服务器的套接字。 当连接建立时,服务器会创建一个Socket对象。客户端和服务器现在可以通过对Socket对象的写入和读取来进行进行通信。 java.net.Socket类代表一个套接字,并且java.net.ServerSocket类为服务器程序提供了一种来监听客户端,并与他们建立连接的机制。 以下步骤在两台计算机之间使用套接字建立TCP连接时会出现: * 服务器实例化一个ServerSocket对象,表示通过服务器上的端口通信。 * 服务器调用 ServerSocket类 的accept()方法,该方法将一直等待,直到客户端连接到服务器上给定的端口。 * 服务器正在等待时,一个客户端实例化一个Socket对象,指定服务器名称和端口号来请求连接。 * Socket类的构造函数试图将客户端连接到指定的服务器和端口号。如果通信被建立,则在客户端创建一个Socket对象能够与服务器进行通信。 * 在服务器端,accept()方法返回服务器上一个新的socket引用,该socket连接到客户端的socket。 连接建立后,通过使用I/O流在进行通信。每一个socket都有一个输出流和一个输入流。客户端的输出流连接到服务器端的输入流,而客户端的输入流连接到服务器端的输出流。 TCP是一个双向的通信协议,因此数据可以通过两个数据流在同一时间发送.以下是一些类提供的一套完整的有用的方法来实现sockets。 -------------------- ## ServerSocket 类的方法 ## 服务器应用程序通过使用java.net.ServerSocket类以获取一个端口,并且侦听客户端请求。 ServerSocket类有四个构造方法: <table style="margin:4px 0px; padding:0px; width:818px; table-layout:fixed; border-collapse:collapse; border-spacing:0px"> <tbody style="margin:0px; padding:0px"> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">序号</span></td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px; text-align:center"> <span style="margin:0px; padding:0px">方法描述</span></td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 1</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public ServerSocket(int port) throws IOException</span><br style="margin:0px; padding:0px"> 创建绑定到特定端口的服务器套接字。</td> </tr> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 2</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public ServerSocket(int port, int backlog) throws IOException</span><br style="margin:0px; padding:0px"> 利用指定的 backlog 创建服务器套接字并将其绑定到指定的本地端口号。</td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 3</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public ServerSocket(int port, int backlog, InetAddress address) throws IOException</span><br style="margin:0px; padding:0px"> 使用指定的端口、侦听 backlog 和要绑定到的本地 IP 地址创建服务器。</td> </tr> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 4</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public ServerSocket() throws IOException</span><br style="margin:0px; padding:0px"> 创建非绑定服务器套接字。</td> </tr> </tbody> </table> 创建非绑定服务器套接字。 如果ServerSocket构造方法没有抛出异常,就意味着你的应用程序已经成功绑定到指定的端口,并且侦听客户端请求。 这里有一些ServerSocket类的常用方法: <table style="margin:4px 0px; padding:0px; width:818px; table-layout:fixed; border-collapse:collapse; border-spacing:0px"> <tbody style="margin:0px; padding:0px"> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">序号</span></td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px; text-align:center"> <span style="margin:0px; padding:0px">方法描述</span></td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 1</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public int getLocalPort()</span><br style="margin:0px; padding:0px"> 返回此套接字在其上侦听的端口。</td> </tr> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 2</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public Socket accept() throws IOException</span><br style="margin:0px; padding:0px"> 侦听并接受到此套接字的连接。</td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 3</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public void setSoTimeout(int timeout)</span><br style="margin:0px; padding:0px"> 通过指定超时值启用/禁用 SO_TIMEOUT,以毫秒为单位。</td> </tr> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 4</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public void bind(SocketAddress host, int backlog)</span><br style="margin:0px; padding:0px"> 将 ServerSocket 绑定到特定地址(IP 地址和端口号)。</td> </tr> </tbody> </table> -------------------- ## Socket 类的方法 ## java.net.Socket类代表客户端和服务器都用来互相沟通的套接字。客户端要获取一个Socket对象通过实例化 ,而 服务器获得一个Socket对象则通过accept()方法的返回值。 Socket类有五个构造方法. <table style="margin:4px 0px; padding:0px; width:818px; table-layout:fixed; border-collapse:collapse; border-spacing:0px"> <tbody style="margin:0px; padding:0px"> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">序号</span></td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px; text-align:center"> <span style="margin:0px; padding:0px">方法描述</span></td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 1</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public Socket(String host, int port) throws UnknownHostException, IOException.</span><br style="margin:0px; padding:0px"> 创建一个流套接字并将其连接到指定主机上的指定端口号。</td> </tr> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 2</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public Socket(InetAddress host, int port) throws IOException</span><br style="margin:0px; padding:0px"> 创建一个流套接字并将其连接到指定 IP 地址的指定端口号。</td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 3</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public Socket(String host, int port, InetAddress localAddress, int localPort) throws IOException.</span><br style="margin:0px; padding:0px"> 创建一个套接字并将其连接到指定远程主机上的指定远程端口。</td> </tr> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 4</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public Socket(InetAddress host, int port, InetAddress localAddress, int localPort) throws IOException.</span><br style="margin:0px; padding:0px"> 创建一个套接字并将其连接到指定远程地址上的指定远程端口。</td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 5</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public Socket()</span><br style="margin:0px; padding:0px"> 通过系统默认类型的 SocketImpl 创建未连接套接字</td> </tr> </tbody> </table> 当Socket构造方法返回,并没有简单的实例化了一个Socket对象,它实际上会尝试连接到指定的服务器和端口。 下面列出了一些感兴趣的方法,注意客户端和服务器端都有一个Socket对象,所以无论客户端还是服务端都能够调用这些方法。 <table style="margin:4px 0px; padding:0px; width:818px; table-layout:fixed; border-collapse:collapse; border-spacing:0px"> <tbody style="margin:0px; padding:0px"> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">序号</span></td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px; text-align:center"> <span style="margin:0px; padding:0px">方法描述</span></td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 1</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public void connect(SocketAddress host, int timeout) throws IOException</span><br style="margin:0px; padding:0px"> 将此套接字连接到服务器,并指定一个超时值。</td> </tr> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 2</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public InetAddress getInetAddress()</span><br style="margin:0px; padding:0px"> 返回套接字连接的地址。</td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 3</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public int getPort()</span><br style="margin:0px; padding:0px"> 返回此套接字连接到的远程端口。</td> </tr> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 4</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public int getLocalPort()</span><br style="margin:0px; padding:0px"> 返回此套接字绑定到的本地端口。</td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 5</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public SocketAddress getRemoteSocketAddress()</span><br style="margin:0px; padding:0px"> 返回此套接字连接的端点的地址,如果未连接则返回 null。</td> </tr> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 6</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public InputStream getInputStream() throws IOException</span><br style="margin:0px; padding:0px"> 返回此套接字的输入流。</td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 7</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public OutputStream getOutputStream() throws IOException</span><br style="margin:0px; padding:0px"> 返回此套接字的输出流。</td> </tr> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 8</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">public void close() throws IOException</span><br style="margin:0px; padding:0px"> 关闭此套接字。</td> </tr> </tbody> </table> -------------------- ## InetAddress 类的方法 ## 这个类表示互联网协议(IP)地址。下面列出了Socket编程时比较有用的方法: <table style="margin:4px 0px; padding:0px; width:818px; table-layout:fixed; border-collapse:collapse; border-spacing:0px"> <tbody style="margin:0px; padding:0px"> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">序号</span></td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px; text-align:center"> <span style="margin:0px; padding:0px">方法描述</span></td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 1</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">static InetAddress getByAddress(byte[] addr)</span><br style="margin:0px; padding:0px"> 在给定原始 IP 地址的情况下,返回 InetAddress 对象。</td> </tr> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 2</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">static InetAddress getByAddress(String host, byte[] addr)</span><br style="margin:0px; padding:0px"> 根据提供的主机名和 IP 地址创建 InetAddress。</td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 3</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">static InetAddress getByName(String host)</span><br style="margin:0px; padding:0px"> 在给定主机名的情况下确定主机的 IP 地址。</td> </tr> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 4</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">String getHostAddress() </span><br style="margin:0px; padding:0px"> 返回 IP 地址字符串(以文本表现形式)。</td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 5</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">String getHostName() </span><br style="margin:0px; padding:0px"> 获取此 IP 地址的主机名。</td> </tr> <tr style="margin:0px; padding:0px; background-color:rgb(239,239,239)"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 6</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">static InetAddress getLocalHost()</span><br style="margin:0px; padding:0px"> 返回本地主机。</td> </tr> <tr style="margin:0px; padding:0px"> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> 7</td> <td style="margin:0px; padding:7px 5px; min-width:40px; height:30px; border:1px solid rgb(221,221,221); vertical-align:top; font-size:14px"> <span style="margin:0px; padding:0px">String toString()</span><br style="margin:0px; padding:0px"> 将此 IP 地址转换为 String。</td> </tr> </tbody> </table> -------------------- ## Socket 客户端实例 ## 如下的GreetingClient 是一个客户端程序,该程序通过socket连接到服务器并发送一个请求,然后等待一个响应。 // 文件名 GreetingClient.java import java.net.*; import java.io.*; public class GreetingClient { public static void main(String [] args) { String serverName = args[0]; int port = Integer.parseInt(args[1]); try { System.out.println("Connecting to " + serverName + " on port " + port); Socket client = new Socket(serverName, port); System.out.println("Just connected to " + client.getRemoteSocketAddress()); OutputStream outToServer = client.getOutputStream(); DataOutputStream out = new DataOutputStream(outToServer); out.writeUTF("Hello from " + client.getLocalSocketAddress()); InputStream inFromServer = client.getInputStream(); DataInputStream in = new DataInputStream(inFromServer); System.out.println("Server says " + in.readUTF()); client.close(); }catch(IOException e) { e.printStackTrace(); } } } -------------------- ## Socket 服务端实例 ## 如下的GreetingServer 程序是一个服务器端应用程序,使用Socket来监听一个指定的端口。 // 文件名 GreetingServer.java import java.net.*; import java.io.*; public class GreetingServer extends Thread { private ServerSocket serverSocket; public GreetingServer(int port) throws IOException { serverSocket = new ServerSocket(port); serverSocket.setSoTimeout(10000); } public void run() { while(true) { try { System.out.println("Waiting for client on port " + serverSocket.getLocalPort() + "..."); Socket server = serverSocket.accept(); System.out.println("Just connected to " + server.getRemoteSocketAddress()); DataInputStream in = new DataInputStream(server.getInputStream()); System.out.println(in.readUTF()); DataOutputStream out = new DataOutputStream(server.getOutputStream()); out.writeUTF("Thank you for connecting to " + server.getLocalSocketAddress() + "\nGoodbye!"); server.close(); }catch(SocketTimeoutException s) { System.out.println("Socket timed out!"); break; }catch(IOException e) { e.printStackTrace(); break; } } } public static void main(String [] args) { int port = Integer.parseInt(args[0]); try { Thread t = new GreetingServer(port); t.start(); }catch(IOException e) { e.printStackTrace(); } } } 编译以上 java 代码,并执行以下命令来启动服务,使用端口号为 6066: $ java GreetingServer 6066 Waiting for client on port 6066... 像下面一样开启客户端: $ java GreetingClient localhost 6066 Connecting to localhost on port 6066 Just connected to localhost/127.0.0.1:6066 Server says Thank you for connecting to /127.0.0.1:6066 Goodbye! 红叶岭谷感谢你的观赏 [Java_URL]: http://www.w3cschool.cn/java/java-url-processing.html
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