java socket编程收藏之三(多线程)

(1)Server端

import java.io.*;
import java.net.*;

/**
 *修改 acceptConnections() 以用缺省为 50（或任何您想要的大于 1 的指定数字）实例化 ServerSocket。
 *修改 ServerSocket 的 handleConnection() 以用 ConnectionHandler 的一个实例生成一个新的 Thread。
 * @author Administrator
 */
public class MultithreadedRemoteFileServer {
    int listenPort;
    public MultithreadedRemoteFileServer(int listenPort) {
        this.listenPort=listenPort;
    }
    //允许客户机连接到服务器,等待客户机请求
    public void acceptConnections() {
        try {
            //指定待发数（backlog 值）是5,一次可以放五个请求到队列中
            ServerSocket server = new ServerSocket(listenPort, 5);
            Socket incomingConnection = null;
            while(true) {
                incomingConnection = server.accept();
                handleConnection(incomingConnection);
            }
        }
        catch(BindException e) {
            System.out.println("Unable to bind to port "+listenPort);
        }
        catch(IOException e) {
            System.out.println("Unable to instantiate a ServerSocket on port: "+listenPort);
        }
    }
    //与客户机Socket交互以将客户机所请求的文件的内容发送到客户机
    public void handleConnection(Socket connectionToHandle) {
        new Thread(new ConnectionHandler(connectionToHandle)).start();
    }
    public static void main(String args[]) {
        MultithreadedRemoteFileServer server = new MultithreadedRemoteFileServer(1001);
        server.acceptConnections();
    }
}

import java.io.*;
import java.net.*;

/**
 *修改 acceptConnections() 以用缺省为 50（或任何您想要的大于 1 的指定数字）实例化 ServerSocket。
 *修改 ServerSocket 的 handleConnection() 以用 ConnectionHandler 的一个实例生成一个新的 Thread。
 * @author Administrator
 */
public class MultithreadedRemoteFileServer {
    int listenPort;
    public MultithreadedRemoteFileServer(int listenPort) {        
        this.listenPort=listenPort;
    }
    //允许客户机连接到服务器,等待客户机请求    
    public void acceptConnections() {
        try {
        	//指定待发数（backlog 值）是5,一次可以放五个请求到队列中
            ServerSocket server = new ServerSocket(listenPort, 5);
            Socket incomingConnection = null;
            while(true) {
                incomingConnection = server.accept(); 
                handleConnection(incomingConnection);
            }
        }        
        catch(BindException e) {
            System.out.println("Unable to bind to port "+listenPort);
        } 
        catch(IOException e) {            
            System.out.println("Unable to instantiate a ServerSocket on port: "+listenPort);        
        }
    }
    //与客户机Socket交互以将客户机所请求的文件的内容发送到客户机    
    public void handleConnection(Socket connectionToHandle) { 
        new Thread(new ConnectionHandler(connectionToHandle)).start();
    }
    public static void main(String args[]) {
        MultithreadedRemoteFileServer server = new MultithreadedRemoteFileServer(1001);
        server.acceptConnections();
    }
}

(2)定义一个实现runable接口的类:ConnectionHandler

import java.io.*;
import java.net.*;
/**
 *借用 RemoteFileServer 的 handleConnection() 方法的代码实现 ConnectionHandler 类。
 * @author Administrator
 */
public class ConnectionHandler implements Runnable {
    protected Socket socketToHandle;
    public ConnectionHandler(Socket socketToHandle) {
        this.socketToHandle=socketToHandle;
    }
    public void run() {
        try {
            PrintWriter streamWriter = new PrintWriter(socketToHandle.getOutputStream());
            //读Socket
            BufferedReader streamReader = new BufferedReader(new InputStreamReader(socketToHandle.getInputStream()));
            String fileToRead = streamReader.readLine();
            BufferedReader fileReader = new BufferedReader(new FileReader(fileToRead));
            String line =null;
            while((line=fileReader.readLine())!=null) {
                streamWriter.println(line);//写Socket
            }
            fileReader.close();
            //如果您在关闭streamWriter之前关闭streamReader，则您可以往Socket写任何东西，
            //但却没有任何数据能通过通道（通道被关闭了）
            streamWriter.close();
            streamReader.close();
        }
        catch(Exception e) {
            System.out.println("Error handling a client: "+e);
        e.printStackTrace();
        }
    }
}

import java.io.*;
import java.net.*;
/**
 *借用 RemoteFileServer 的 handleConnection() 方法的代码实现 ConnectionHandler 类。 
 * @author Administrator
 */
public class ConnectionHandler implements Runnable {
    protected Socket socketToHandle;
    public ConnectionHandler(Socket socketToHandle) {
        this.socketToHandle=socketToHandle;
    }
    public void run() {
        try {
            PrintWriter streamWriter = new PrintWriter(socketToHandle.getOutputStream()); 
            //读Socket
            BufferedReader streamReader = new BufferedReader(new InputStreamReader(socketToHandle.getInputStream()));
            String fileToRead = streamReader.readLine();
            BufferedReader fileReader = new BufferedReader(new FileReader(fileToRead)); 
            String line =null;
            while((line=fileReader.readLine())!=null) {
                streamWriter.println(line);//写Socket
            }
            fileReader.close();
            //如果您在关闭streamWriter之前关闭streamReader，则您可以往Socket写任何东西，
            //但却没有任何数据能通过通道（通道被关闭了）
            streamWriter.close();
            streamReader.close();
        }
        catch(Exception e) {
            System.out.println("Error handling a client: "+e);
        e.printStackTrace();
        }
    }
}

(3)Client端

import java.io.*;
import java.net.*;
/**
 *   用您想连接的机器的 IP 地址和端口实例化 Socket。
 *   获取 Socket 上的流以进行读写。
 *   把流包装进 BufferedReader/PrintWriter 的实例，如果这样做能使事情更简单的话。
 *   对 Socket 进行读写。
 *   关闭打开的流。
 * @author Administrator
 */
public class RemoteFileClient {
    protected BufferedReader socketReader;
    protected PrintWriter socketWriter;
    protected String hostIp;
    protected int hostPort;
    /**
     * 构造方法
     */
    public RemoteFileClient(String hostIp, int hostPort) {
        this.hostIp = hostIp;
        this.hostPort=hostPort;
    }
    /**
     * 向服务器请求文件的内容,告诉服务器我们想要什么文件并在服务器传回其内容时接收该内容
     */
    public String getFile(String fileNameToGet) {
        StringBuffer fileLines = new StringBuffer();
        try {
            socketWriter.println(fileNameToGet);
            socketWriter.flush();
            String line = null;
            while((line=socketReader.readLine())!=null)
                fileLines.append(line+"\n");
        }
        catch(IOException e) {
            System.out.println("Error reading from file: "+fileNameToGet);
        }
        return fileLines.toString();
    }
    /**
     * 连接到远程服务器,创建我们的 Socket 并让我们访问该套接字的流
     */
    public void setUpConnection() {
        try {
            Socket client = new Socket(hostIp,hostPort);
            socketReader = new BufferedReader(new InputStreamReader(client.getInputStream()));
            socketWriter = new PrintWriter(client.getOutputStream());
        }
        catch(UnknownHostException e) {
            System.out.println("Error1 setting up socket connection: unknown host at "+hostIp+":"+hostPort);
        }
        catch(IOException e) {
            System.out.println("Error2 setting up socket connection: "+e);
        }
    }
    /**
     * 使用完毕连接后负责“清除”。
     */
    public void tearDownConnection() {
        try {
            socketWriter.close();
            socketReader.close();
        }catch(IOException e) {
            System.out.println("Error tearing down socket connection: "+e);
        }
    }
    public static void main(String args[]) {
        RemoteFileClient remoteFileClient = new RemoteFileClient("127.0.0.1",1001);
        remoteFileClient.setUpConnection();
        StringBuffer fileContents = new StringBuffer();
        fileContents.append(remoteFileClient.getFile("D:/test.txt"));
        //remoteFileClient.tearDownConnection();
        System.out.println(fileContents);
    }
}