JAVA ： Socket和多线程

这几天面试老是被问到你对Java并发和网络编程熟不熟。

姐比较实诚，我直明，看过资料，没动过手，于是被鄙视之。 = =以后我的博客应该叫荒废一年的IT女码农边学边面。。。

干脆回来花了点时间写了程序，练个手。

Socket Server 处理多个Socket client的写入请求，然后Socket Server将读取的数据写入一个和client共享的Queue中。也就是server是这个Queue的生产者，Client又是这个Queue的消费者。

Queue代码：

import java.util.concurrent.locks.Condition;import java.util.concurrent.locks.ReentrantLock;public class SafeQueue {    private final Byte[] buffer;    private int size;    private int capacity;    private int start;    private int end;    private ReentrantLock lock;    private Condition notFull;    private Condition notEmpty;    private static SafeQueue queue;    private SafeQueue(int size) {        this.size = size;        this.capacity = size;        this.start = 0;        this.end = 0;        buffer = new Byte[size];        lock = new ReentrantLock(true);        notFull = lock.newCondition();        notEmpty = lock.newCondition();    }    public static SafeQueue getSingleInstance() {        if (queue == null) {            queue = new SafeQueue(20);            for (int i = 0; i < 20; i++ ) {                try {                    queue.put((byte)i);                } catch (InterruptedException e) {                    // TODO Auto-generated catch block                    e.printStackTrace();                }            }        }        return queue;    }    public void put(Byte newElement) throws InterruptedException {        ReentrantLock lock = this.lock;        lock.lockInterruptibly();        try {            try {                while (capacity == 0) {                    notFull.await();                }            } catch (InterruptedException e) {                    notFull.signal();                    e.printStackTrace();            }            buffer[end] = newElement;            end = (end + 1) % this.size;            capacity--;            notEmpty.signal();        }         finally{            lock.unlock();        }            }    public Byte peek() {        ReentrantLock lock = this.lock;        lock.lock();        try {            try {                if(capacity == size) {                    notEmpty.await();                }            } catch (InterruptedException e) {                notEmpty.signal();            }            Byte result = null;            result = buffer[start];            buffer[start] = null;            start = (start + 1) % size;            capacity++;            notFull.signal();            return result;        } finally {            lock.unlock();        }    }    public byte[] peek(int length) {        ReentrantLock lock = this.lock;        lock.lock();        try{            byte[] result = new byte[length];            for(int i = 0; i < length; i++) {                try {                    if(capacity == size) {                        notEmpty.await();                    }                } catch (InterruptedException e) {                    notEmpty.signal();                }                result[i] = buffer[start];                buffer[start] = null;                start = (start + 1) % size;                capacity++;                notFull.signal();            }            return result;        }        finally{            lock.unlock();        }    }    public void put(byte[] elements, int length) throws InterruptedException {        ReentrantLock lock = this.lock;        lock.lockInterruptibly();        try {            for (int i = 0; i < length; i++) {                try {                    while (capacity == 0) {                        notFull.await();                    }                } catch (InterruptedException e) {                        notFull.signal();                        e.printStackTrace();                }                buffer[end] = elements[i];                end = (end + 1) % this.size;                capacity--;                notEmpty.signal();            }        }        finally{            lock.unlock();        }    }    public int size() {        ReentrantLock lock = this.lock;        lock.lock();        try {            return size - capacity;        }        finally{            lock.unlock();        }    }    public String toString() {        String re = "";        for (int i = 0; i < 20; i++) {            re+=buffer[i]+ "|";        }        return re;    }}

Server代码：

import java.io.BufferedInputStream;import java.io.IOException;import java.net.ServerSocket;import java.net.Socket;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;public class Server extends Thread {    ServerSocket server;    /**     * @param args     */     //写个Socket发送数据    public Server() {        try {            server = new ServerSocket(9994);        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }        public void run() {        Socket socket = null;        while(true) {            try {                socket = server.accept();                executorService.execute(new DealThread(socket));            } catch (IOException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }    }    public static void main(String[] args) {        // TODO Auto-generated method stub        new Server().start();    }}class DealThread implements Runnable {    Socket socket = null;    SafeQueue queue = SafeQueue.getSingleInstance();     public DealThread(Socket socket) {        this.socket = socket;    }    @Override    public void run() {        try {            byte[] result = new byte[5];            System.out.println("New connection accepted "+socket.getInetAddress()+":"+socket.getPort()+ socket.getReceiveBufferSize());            BufferedInputStream reader = new BufferedInputStream(socket.getInputStream());            int length = reader.read(result,  0, result.length);            while(length >= 0) {                try {                    queue.put(result, length);                    System.out.println("server: " + queue);                    length = reader.read(result, 0, result.length);                } catch (InterruptedException e) {                    // TODO Auto-generated catch block                    e.printStackTrace();                }                            }        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        // TODO Auto-generated method stub            }        }

Client：

import java.io.BufferedOutputStream;import java.io.IOException;import java.net.InetAddress;import java.net.Socket;import java.net.UnknownHostException;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;public class Customer {    /**     * @param args     */    public static void main(String[] args) {        // TODO Auto-generated method stub        new Server().start();        ExecutorService executorService =  Executors.newFixedThreadPool(10);        for(int i = 0; i< 4; i++) {            executorService.execute(new CustomerThread());        }    }}class CustomerThread implements Runnable {    Socket socket;    SafeQueue queue = SafeQueue.getSingleInstance();    public CustomerThread() {        try {            socket = new Socket(InetAddress.getLocalHost(), 9994);        } catch (UnknownHostException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }    @Override    public void run() {       while(true) {           byte[] result = queue.peek(5);           BufferedOutputStream writer = null;           try {               writer = new BufferedOutputStream(socket.getOutputStream());               writer.write(result);               writer.flush();               System.out.println(queue);           } catch (IOException e) {               // TODO Auto-generated catch block               e.printStackTrace();           }    }    }}