Java如何通過Socket實現TCP服務端
Socket 通常也稱作“套接字”，Java如何通過Socket實現TCP服務端？下面百分網小編帶大家一起來看看詳細內容，希望對大家有所幫助!想了解更多相關信息請持續關注我們應屆畢業生考試網!
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”向網絡發出請求或者應答網絡請求。Socket和ServerSocket類庫位于Java.NET包中。ServerSocket用于服務器端，Socket是建立網絡連接時使用的。在連接成功時，應用程序兩端都會產生一個Socket實例，操作這個實例，完成所需的會話。對于一個網絡連接來說，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; //服務器狀態標志
private static final int BUFFER_SIZE = 512; //數據接收字符數組大小
//構造函數/
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();
}
/**
* 服務器向客戶端發送數據
* @param bytes[]:待發送的字符數組
* @param key 客戶端的key,為空或""時表示數據群發
* @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);
}
}
/**
* 服務器向客戶端發送數據
* @param key 客戶端的key,為空或""時表示數據群發
* @param msgStr:待發送的字符串
* @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("服務器線程已經啟動"); while(true){
try {
while(flag){
logger.info("服務器線程在監聽狀態中");
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();
}
}
}
/**
* 處理連接后的數據接收請求內部類
* @author xiang
*
*/
private class SocketThread extends Thread{
private Socket socket;
private String key;
private OutputStream out;
private InputStream in;
//構造函數
public SocketThread(Socket socket,String key) {
this.socket = socket;
this.key = key;
}
/**
* 發送數據
* @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());
/**************************************************************
*
* 接收數據后的處理過程
*
**************************************************************/
}
// 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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