（转载）Java Socket实战之五:使用加密协议传输对象

前面几篇博文提到了Socket中一些常用的用法，但是对于一些有安全要求的应用就需要加密传输的数据，此时就需要用到SSLSocket了。

还是一样需要一个实现了java.io.Serializable接口的简单Java对象：

package com.googlecode.garbagecan.test.socket.ssl;

public class User implements java.io.Serializable {
    private static final long serialVersionUID = 1L;
    private String name;
    private String password;

    public User() {

    }

    public User(String name, String password) {
        this.name = name;
        this.password = password;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

}

SSL Server类，这里需要用到ServerSocketFactory类来创建SSLServerSocket类实例，然后在通过SSLServerSocket来获取SSLSocket实例，这里考虑到面向对象中的面向接口编程的理念，所以代码中并没有出现SSLServerSocket和SSLSocket，而是用了他们的父类ServerSocket和Socket。在获取到ServerSocket和Socket实例以后，剩下的代码就和不使用加密方式一样了。

package com.googlecode.garbagecan.test.socket.ssl;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.net.ServerSocketFactory;
import javax.net.ssl.SSLServerSocketFactory;

public class MyServer {

    private final static Logger logger = Logger.getLogger(MyServer.class.getName());

    public static void main(String[] args) {
        try {
            ServerSocketFactory factory = SSLServerSocketFactory.getDefault();
            ServerSocket server = factory.createServerSocket(10000);

            while (true) {
                Socket socket = server.accept();
                invoke(socket);
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    private static void invoke(final Socket socket) throws IOException {
        new Thread(new Runnable() {
            public void run() {
                ObjectInputStream is = null;
                ObjectOutputStream os = null;
                try {
                    is = new ObjectInputStream(new BufferedInputStream(socket.getInputStream()));
                    os = new ObjectOutputStream(socket.getOutputStream());

                    Object obj = is.readObject();
                    User user = (User)obj;
                    System.out.println("user: " + user.getName() + "/" + user.getPassword());

                    user.setName(user.getName() + "_new");
                    user.setPassword(user.getPassword() + "_new");

                    os.writeObject(user);
                    os.flush();
                } catch (IOException ex) {
                    logger.log(Level.SEVERE, null, ex);
                } catch(ClassNotFoundException ex) {
                    logger.log(Level.SEVERE, null, ex);
                } finally {
                    try {
                        is.close();
                    } catch(Exception ex) {}
                    try {
                        os.close();
                    } catch(Exception ex) {}
                    try {
                        socket.close();
                    } catch(Exception ex) {}
                }
            }
        }).start();
    }
}

SSL Client类和SSL Server类类似，只是将其中获取Socket的方式有所变化，其余的代码也和不使用加密方式一样。

package com.googlecode.garbagecan.test.socket.ssl;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.Socket;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.net.SocketFactory;
import javax.net.ssl.SSLSocketFactory;

public class MyClient {

private final static Logger logger = Logger.getLogger(MyClient.class.getName());

    public static void main(String[] args) throws Exception {
        for (int i = 0; i < 100; i++) {
            Socket socket = null;
            ObjectOutputStream os = null;
            ObjectInputStream is = null;

            try {
                SocketFactory factory = SSLSocketFactory.getDefault();
                socket = factory.createSocket("localhost", 10000);

                os = new ObjectOutputStream(socket.getOutputStream());
                User user = new User("user_" + i, "password_" + i);
                os.writeObject(user);
                os.flush();

                is = new ObjectInputStream(new BufferedInputStream(socket.getInputStream()));
                Object obj = is.readObject();
                if (obj != null) {
                    user = (User)obj;
                    System.out.println("user: " + user.getName() + "/" + user.getPassword());
                }
            } catch(IOException ex) {
                logger.log(Level.SEVERE, null, ex);
            } finally {
                try {
                    is.close();
                } catch(Exception ex) {}
                try {
                    os.close();
                } catch(Exception ex) {}
                try {
                    socket.close();
                } catch(Exception ex) {}
            }
        }
    }
}

代码写完了，下面就需要产生keystore文件了，运行下面的命令

keytool -genkey -alias mysocket -keyalg RSA -keystore mysocket.jks

在提示输入项中，密码项自己给定，其它都不改直接回车，这里我使用的密码是“mysocket”。

运行Server

java -Djavax.net.ssl.keyStore=mysocket.jks -Djavax.net.ssl.keyStorePassword=mysocket com.googlecode.garbagecan.test.socket.ssl.MyServer

运行Client

java -Djavax.net.ssl.trustStore=mysocket.jks  -Djavax.net.ssl.trustStorePassword=mysocket com.googlecode.garbagecan.test.socket.ssl.MyClient