Java 网络编程 —— 创建多线程服务器 - IT评测·应用市场-qidao123.com

while (true) {
Socket socket = null;
try {
// 接收客户连接
socket = serverSocket.accept();
// 从socket中获得输入流与输出流，与客户通信
...
} catch(IOException e) {
e.printStackTrace()
} finally {
try {
if(socket != null) {
// 断开连接
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}

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public class EchoServer {
private int port = 8000;
private ServerSocket serverSocket;
public EchoServer() throws IOException {
serverSocket = new ServerSocket(port);
System.out.println("服务器启动");
}
public void service() {
while(true) {
Socket socket = null;
try {
// 接教客户连接
socket = serverSocket.accept();
// 创建一个工作线程
Thread workThread = new Thread(new Handler(socket));
// 启动工作线程
workThread.start();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public static void main(String args[])throws TOException {
new EchoServer().service();
}
// 负责与单个客户的通信
class Handler implements Runnable {
private Socket socket;
pub1ic Handler(Socket socket) {
this.socket = socket;
}
private PrintWriter getWriter(Socket socket) throws IOException {...}
private BufferedReader getReader(Socket socket) throws IOException {...}
public String echo(String msg) {...}
public void run() {
try {
System.out.println("New connection accepted" + socket.getInetAddress() + ":" + socket.getPort());
BufferedReader br = getReader(socket);
PrintWriter pw = getWriter(socket);
String msg = null;
// 接收和发送数据，直到通信结束
while ((msg = br.readLine()) != null) {
System.out.println("from "+ socket.getInetAddress() + ":" + socket.getPort() + ">" + msg);
pw.println(echo(msg));
if (msg.equals("bye")) break;
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
// 断开连接
if(socket != nulll) socket.close();
} catch (IOException e) {
e,printStackTrace();
}
}
}
}
}

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public class ThreadPool extends ThreadGroup {
// 线程池是否关闭
private boolean isClosed = false;
// 表示工作队列
private LinkedList<Runnable> workQueue;
// 表示线程池ID
private static int threadPoolID;
// 表示工作线程ID
// poolSize 指定线程池中的工作线程数目
public ThreadPool(int poolSize) {
super("ThreadPool-"+ (threadPoolID++));
setDaemon(true);
// 创建工作队列
workQueue = new LinkedList<Runnable>();
for (int i = 0; i < poolSize; i++) {
// 创建并启动工作线程
new WorkThread().start();
}
}
/**
* 向工作队列中加入一个新任务，由工作线程去执行任务
*/
public synchronized void execute(Runnable tank) {
// 线程池被关则抛出IllegalStateException异常
if(isClosed) {
throw new IllegalStateException();
}
if(task != null) {
workQueue.add(task);
// 唤醒正在getTask()方法中等待任务的工作线限
notify();
}
}
/**
* 从工作队列中取出一个任务，工作线程会调用此方法
*/
protected synchronized Runnable getTask() throws InterruptedException {
while(workQueue,size() == 0) {
if (isClosed) return null;
wait(); // 如果工作队列中没有任务，就等待任务
}
return workQueue.removeFirst();
}
/**
* 关闭线程池
*/
public synchronized void close() {
if(!isClosed) {
isClosed = true;
// 清空工作队列
workQueue.clear();
// 中断所有的工作线程，该方法继承自ThreadGroup类
interrupt();
}
}
/**
* 等待工作线程把所有任务执行完
*/
public void join() {
synchronized (this) {
isClosed = true;
// 唤醒还在getTask()方法中等待任务的工作线程
notifyAll();
}
Thread[] threads = new Thread[activeCount()];
// enumerate()方法继承自ThreadGroup类获得线程组中当前所有活着的工作线程
int count = enumerate(threads);
// 等待所有工作线程运行结束
for(int i = 0; i < count; i++) {
try {
// 等待工作线程运行结束
threads[i].join();
} catch((InterruptedException ex) {}
}
}
/**
* 内部类:工作线程
*/
private class WorkThread extends Thread {
public WorkThread() {
// 加入当前 ThreadPool 线程组
super(ThreadPool.this, "WorkThread-" + (threadID++));
}
public void run() {
// isInterrupted()方法承自Thread类，判断线程是否被中断
while (!isInterrupted()) {
Runnable task = null;
try {
// 取出任务
task = getTask();
} catch(InterruptedException ex) {}
// 如果 getTask() 返回 nu11 或者线程执行 getTask() 时被中断，则结束此线程
if(task != null) return;
// 运行任务，异常在catch代码块中被捕获
try {
task.run();
} catch(Throwable t) {
t.printStackTrace();
}
}
}
}
}

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publlc class EchoServer {
private int port = 8000;
private ServerSocket serverSocket;
private ThreadPool threadPool; // 线程港
private final int POOL_SIZE = 4; // 单个CPU时线程池中工作线程的数目
public EchoServer() throws IOException {
serverSocket = new ServerSocket(port);
// 创建线程池
// Runtime 的 availableProcessors() 方法返回当前系统的CPU的数目
// 系统的CPU越多，线程池中工作线程的数目也越多
threadPool= new ThreadPool(
Runtime.getRuntime().availableProcessors() * POOL_SIZE);
System.out.println("服务器启动");
}
public void service() {
while (true) {
Socket socket = null;
try {
socket = serverSocket.accept();
// 把与客户通信的任务交给线程池
threadPool.execute(new Handler(socket));
} catch(IOException e) {
e.printStackTrace();
}
}
}
public static void main(String args[])throws TOException {
new EchoServer().service();
}
// 负责与单个客户的通信，与上例类似
class Handler implements Runnable {...}
}

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public class Echoserver {
private int port = 8000;
private ServerSocket serverSocket;
// 线程池
private ExecutorService executorService;
// 单个CPU时线程池中工作线程的数目
private final int POOL_SIZE = 4;
public EchoServer() throws IOException {
serverSocket = new ServerSocket(port);
// 创建线程池
// Runtime 的 availableProcessors() 方法返回当前系统的CPU的数目
// 系统的CPU越多，线程池中工作线程的数目也越多
executorService = Executors.newFixedThreadPool(
Runtime.getRuntime().availableProcessors() * POOL_SIZE);
System.out.println("服务器启动");
}
public void service() {
while(true) {
Socket socket = null;
try {
socket = serverSocket.accept();
executorService.execute(new Handler(socket));
} catch(IOException e) {
e.printStackTrace();
}
}
}
public static void main(String args[])throws TOException {
new EchoServer().service();
}
// 负责与单个客户的通信，与上例类似
class Handler implements Runnable {...}
}

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