Java通過 Socket 實現(xiàn) TCP服務端
1 Java Socket簡介
所謂socket 通常也稱作”套接字“,用于描述IP地址和端口,是一個通信鏈的句柄。應用程序通常通過”套接字”向網(wǎng)絡發(fā)出請求或者應答網(wǎng)絡請求。Socket和ServerSocket類庫位于Java.NET包中。ServerSocket用于服務器端,Socket是建立網(wǎng)絡連接時使用的。在連接成功時,應用程序兩端都會產(chǎn)生一個Socket實例,操作這個實例,完成所需的會話。對于一個網(wǎng)絡連接來說,套接字是平等的,并沒有差別,不因為在服務器端或在客戶端而產(chǎn)生不同級別。
2 TCPServer代碼實例
import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.ServerSocket; import java.net.Socket; import java.util.Date; import java.util.HashMap; import java.util.Map; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * TCP服務器端,單例模式 * @author xiang * */ public class TCPServer implements Runnable { private static final Logger logger = LoggerFactory.getLogger(TCPServer.class); //成員變量/ private static TCPServer serverInstance; private static Map<String, SocketThread> socketMaps = new HashMap<String,SocketThread>(); //每個客戶端連接時都會新建一個SocketThread與之對應 private static ServerSocket serverSocket; //服務器套接字 private static int serPort = 9999; //服務器端口號 private static boolean flag; //服務器狀態(tài)標志 private static final int BUFFER_SIZE = 512; //數(shù)據(jù)接收字符數(shù)組大小 //構(gòu)造函數(shù)/ private TCPServer() { } /** * 獲取實例 * @return TCPServer實例serverInstance */ public static TCPServer getServerInstance(){ if(serverInstance==null) serverInstance = new TCPServer(); return serverInstance; } /** * 開啟服務器 * @throws IOException */ public void openTCPServer() throws IOException{ if(serverSocket==null || serverSocket.isClosed()){ serverSocket = new ServerSocket(serPort); flag = true; } } /** * 關(guān)閉服務器 * @throws IOException */ public void closeTCPServer() throws IOException{ flag = false; if(serverSocket!=null) serverSocket.close(); /*for (Map.Entry<String, SocketThread> entry : socketMaps.entrySet()) { System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue()); } */ for (SocketThread value : socketMaps.values()) value.closeConnect(); socketMaps.clear(); } /** * 服務器向客戶端發(fā)送數(shù)據(jù) * @param bytes[]:待發(fā)送的字符數(shù)組 * @param key 客戶端的key,為空或""時表示數(shù)據(jù)群發(fā) * @throws IOException */ public void sendMessage(String key,byte[] msgBytes){ if(key==null||key.equals("")){ for (SocketThread value : socketMaps.values()) value.sendMassage(msgBytes); }else{ SocketThread thread = socketMaps.get(key); if(thread!=null) thread.sendMassage(msgBytes); } } /** * 服務器向客戶端發(fā)送數(shù)據(jù) * @param key 客戶端的key,為空或""時表示數(shù)據(jù)群發(fā) * @param msgStr:待發(fā)送的字符串 * @throws IOException */ public void sendMessage(String key,String msgStr){ byte[] sendByte = msgStr.getBytes(); if(key==null||key.equals("")){ for (SocketThread value : socketMaps.values()) value.sendMassage(sendByte); }else{ SocketThread thread = socketMaps.get(key); if(thread!=null) thread.sendMassage(sendByte); } } @Override public void run() { logger.info("服務器線程已經(jīng)啟動"); while(true){ try { while(flag){ logger.info("服務器線程在監(jiān)聽狀態(tài)中"); Socket socket = serverSocket.accept(); String key = socket.getRemoteSocketAddress().toString(); SocketThread thread = new SocketThread(socket,key); thread.start(); socketMaps.put(key, thread); logger.info("有客戶端連接:"+key); } } catch (Exception e) { e.printStackTrace(); } } } /** * 處理連接后的數(shù)據(jù)接收請求內(nèi)部類 * @author xiang * */ private class SocketThread extends Thread{ private Socket socket; private String key; private OutputStream out; private InputStream in; //構(gòu)造函數(shù) public SocketThread(Socket socket,String key) { this.socket = socket; this.key = key; } /** * 發(fā)送數(shù)據(jù) * @param bytes * @throws IOException */ public void sendMassage(byte[] bytes){ try { if(out==null) out = socket.getOutputStream(); out.write(bytes); } catch (Exception e) { e.printStackTrace(); try { closeConnect(); } catch (IOException e1) { e1.printStackTrace(); } socketMaps.remove(key); } } /** * 關(guān)閉連接,釋放資源 * @throws IOException */ public void closeConnect() throws IOException{ if(out!=null) out.close(); if(in!=null) in.close(); if(socket!=null && socket.isConnected()) socket.close(); } @Override public void run() { byte[] receivBuf = new byte[BUFFER_SIZE]; int recvMsgSize; try { in = socket.getInputStream(); out = socket.getOutputStream(); while ((recvMsgSize = in.read(receivBuf)) != -1) { String receivedData = new String(receivBuf, 0, recvMsgSize); System.out.println("Reverve form[port" + socket.getPort() + "]:" + receivedData); System.out.println("Now the size of socketMaps is" + socketMaps.size()); /************************************************************** * * 接收數(shù)據(jù)后的處理過程 * **************************************************************/ } // response to client byte[] sendByte = "The Server has received".getBytes(); // out.write(sendByte, 0, sendByte.length); out.write(sendByte); System.out.println("To Cliect[port:" + socket.getPort() + "] 回復客戶端的消息發(fā)送成功"); closeConnect(); socketMaps.remove(key); } catch (Exception e) { e.printStackTrace(); try { closeConnect(); } catch (IOException e1) { e1.printStackTrace(); } } } ////////////// public int getport(){ return socket.getPort(); } } //. end SocketThread }
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