Java 网络编程（续）

SocketChannel socketChannel = SocketChannel.open();

socketChannel.connect(new InetSocketAddress("http://jenkov.com", 80));

//Server

//Selector 构建

Selector selector = Selector.open();

//Channel 构建

ServerSocketChannel servChannel = ServerSocketChannel.open();

servChannel.configureBlocking(false); // 设置非阻塞模式

servChannel.socket().bind(new InetSocketAddress(8001), 1024);// 设定 8001 端口

servChannel.register(selector, SelectionKey.OP_ACCEPT); //selector 绑定

//selector 一次遍历所有 channel

selector.select(1000); // 最多等待堵塞 1000ms

Set<SelectionKey> selectedKeys = selector.selectedKeys(); // 获得所有有数据响应的 key

Iterator<SelectionKey> it = selectedKeys.iterator();

while (it.hasNext()) {

    SelectionKey key = it.next();

    it.remove();

    try {

        //Handle

    } catch (Exception e) {

        if (key != null) {

            key.cancel();

            if (key.channel() != null)

                key.channel().close();

        }

    }

}

//Handle

if(key.isValid()) {

    if(key.isAcceptable()) {

        // Accept the new connection

        ServerSocketChannel ssc = (ServerSocketChannel) key.channel();

        SocketChannel sc = ssc.accept();

        sc.configureBlocking(false);

        // Add the new connection to the selector

        sc.register(selector, SelectionKey.OP_READ);

    }

    if(key.isReadable()) {

        //Read the data

    }

}

//Client

//Selector 构建

Selector selector = Selector.open();

//Channel 构建

SocketChannel socketChannel = SocketChannel.open();

socketChannel.configureBlocking(false); // 设置非阻塞模式

// 如果直接连接成功，则注册到多路复用器上，发送请求消息，读应答

if (socketChannel.connect(new InetSocketAddress("127.0.0.1", 8001))) {

    socketChannel.register(selector, SelectionKey.OP_READ);

    //doWrite

} else {

    socketChannel.register(selector, SelectionKey.OP_CONNECT);

}

//Handle

if(key.isValid()) {

    // 判断是否连接成功

    SocketChannel sc = (SocketChannel) key.channel();

    if(key.isConnectable()) {

        if (sc.finishConnect()) {

                    sc.register(selector, SelectionKey.OP_READ);                    

                } 

    }

    if(key.isReadable()) {

        //Read the data

    }

}

//doWrite

byte[] str = //TODO

ByteBuffer writeBuffer = ByteBuffer.allocate(str.length); //Buffer 分配内存

writeBuffer.put(str); //str 写入 Buffer

writeBuffer.flip(); // 读写模式切换

sc.write(writeBuffer); //Buffer 数取数据到 Channel

// 服务器通道建立

AsynchronousServerSocketChannel server = AsynchronousServerSocketChannel.open();

server.bind(new InetSocketAddress("localhost", 8001));

// 服务器接受客户端请求，成功接收后自动回调

server.accept(null, new CompletionHandler<AsynchronousSocketChannel, Object>() {

    @Override

    public void completed(AsynchronousSocketChannel channel, Object attachment) {

        //TODO

    }

    @Override

    public void failed(Throwable exc, Object attachment) {

        //TODO

    }

});

// 客户端通道建立

AsynchronousSocketChannel channel = AsynchronousSocketChannel.open();

// 连接成功后自动回调

channel.connect(new InetSocketAddress("localhost", 8001), null, new CompletionHandler<Void, Void>() {

    @Override

    public void completed(Integer result, Object attachment) {

        //TODO

    }

    @Override

    public void failed(Throwable exc, Object attachment) {

        //TODO

    }

});

//from BiliBili

//Server

EventLoopGroup bossGroup = new NioEventLoopGroup();

EventLoopGroup workGroup = new NioEventLoopGroup();

ServerBootstrap bootstrap = new ServerBootstrap();

// 链式编程，设置服务器

bootstrap.group(bossGroup,workGroup) // 设置两个线程组

        .channel(NioServerSocketChannel.class) // 使用 NioServerSocketChannel 作为服务器通道的实现

        .option(ChannelOption.SO_BACKLOG,128) // 设置线程队列得到连接个数

        .childOption(ChannelOption.SO_KEEPALIVE,true) // 设置保持活动连接状态

        .childHandler(new ChannelInitializer<SocketChannel>() { // 给 workGroup 的 EventLoop 对应的管道设置处理器

            @Override

            public void initChannel(SocketChannel ch) throws Exception {

                ch.pipeline().addLast(new ServerHandler()); // 添加处理类

            }

        });

// 绑定一个端口并同步，生成了一个 ChannelFuture 对象

ChannelFuture cf =bootstrap.bind(6668).sync();

// 对关闭通道进行监听

cf.channel().closeFuture().sync();

//ServerHandler extends ChannelInboundHandlerAdapter

@Override

public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception{

    ByteBuf in = (ByteBuf) msg;

    String content = in.toString(CharsetUtil.UTF_8);

    System.out.println("Server received: " + content);

    System.out.println("Client address: "+ctx.channel().remoteAddress());

    ByteBuf out = ctx.alloc().buffer(1024);

    out.writeBytes((content + " 666").getBytes());

    ctx.write(out);

}

@Override

public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {

    ctx.writeAndFlush(Unpooled.EMPTY_BUFFER)

            .addListener(ChannelFutureListener.CLOSE);

}

@Override

public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {

    cause.printStackTrace();

    ctx.close();

}

//Client

EventLoopGroup eventExecutors = new NioEventLoopGroup();

try {

    Bootstrap bootstrap = new Bootstrap();

    bootstrap.group(eventExecutors) // 设置两个线程组

            .channel(NioSocketChannel.class) // 使用 NioSocketChannel 作为服务器通道的实现

            .handler(new ChannelInitializer<SocketChannel>() { // 给 eventExecutors 的 EventLoop 对应的管道设置处理器

                @Override

                public void initChannel(SocketChannel ch) throws Exception {

                    ch.pipeline().addLast(new ClientHandler()); // 添加处理类

                }

            });

    System.out.println("...客户端 is ready...");

    // 启动客户端连接服务端

    ChannelFuture channelFuture = bootstrap.connect("127.0.0.1",6668).sync();

    // 给关闭通道进行监听

    channelFuture.channel().closeFuture().sync();

}finally {

    // 优雅关闭

    eventExecutors.shutdownGracefully();

}

//ClientHandler extends ChannelInboundHandlerAdapter

@Override

public void channelActive(ChannelHandlerContext ctx) throws Exception {

    ctx.writeAndFlush(Unpooled.copiedBuffer("Netty rocks!", CharsetUtil.UTF_8));

}

@Override

public void channelRead(ChannelHandlerContext ctx, Object msg) {

    ByteBuf buf = (ByteBuf) msg;

    System.out.println("Client received: " + buf.toString(CharsetUtil.UTF_8));

    System.out.println("Server address: "+ctx.channel().remoteAddress());

}

@Override

public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {

    cause.printStackTrace();

    ctx.close();

}

//Receive

public class MailClientRecv {

  private Session session;

  private Store store;

  private String username = "chenliangyu1980@126.com";

  private String password = "1234567899";

  private String popServer = "pop.126.com";

  public void init()throws Exception

  {

    // 设置属性

    Properties  props = new Properties();

    props.put("mail.store.protocol", "pop3");

    props.put("mail.imap.class", "com.sun.mail.imap.IMAPStore");

    props.put("mail.pop3.class", "com.sun.mail.pop3.POP3Store");    

    // 创建 Session 对象

    session = Session.getInstance(props,null);

    session.setDebug(false); // 输出跟踪日志

    // 创建 Store 对象

    store = session.getStore("pop3");

    // 连接到收邮件服务器

    store.connect(popServer,username,password);

  }  

  public void receiveMessage()throws Exception

  {

    String folderName = "inbox";

    Folder folder=store.getFolder(folderName);

    if(folder==null)

    {

        throw new Exception(folderName+"邮件夹不存在");

    }

    // 打开信箱

    folder.open(Folder.READ_ONLY);

    System.out.println("您的收件箱有"+folder.getMessageCount()+"封邮件.");

    System.out.println("您的收件箱有"+folder.getUnreadMessageCount()+"封未读的邮件.");

    // 读邮件

    Message[] messages=folder.getMessages();

    //for(int i=1;i<=messages.length;i++)

    for(int i=1;i<=3;i++)  

    {

      System.out.println("------第"+i+"封邮件-------");

      // 打印邮件信息

      Message message = messages[i];

      //folder.getMessage(i).writeTo(System.out);

      System.out.println((message.getFrom())[0]);

      System.out.println(message.getSubject());

      System.out.println();

    }

    folder.close(false);  // 关闭邮件夹

  }

  public void close()throws Exception

  {

    store.close();

  }

  public static void main(String[] args)throws Exception {

    MailClientRecv client=new MailClientRecv();

    // 初始化

    client.init();

    // 接收邮件

    client.receiveMessage();

    // 关闭连接

    client.close();

  }

}

//Send

public class MailClientSend {

  private Session session;

  private Transport transport;

  private String username = "lychen@sei.ecnu.edu.cn";

  private String password = "1234567899";

  private String smtpServer = "webmail.ecnu.edu.cn";

  public void init()throws Exception

  {

    // 设置属性

    Properties  props = new Properties();

    props.put("mail.transport.protocol", "smtp");

    props.put("mail.smtp.class", "com.sun.mail.smtp.SMTPTransport");

    props.put("mail.smtp.host", smtpServer); // 设置发送邮件服务器

    props.put("mail.smtp.port", "25");

    props.put("mail.smtp.auth", "true"); //SMTP 服务器需要身份验证    

    // 创建 Session 对象

    session = Session.getInstance(props,new Authenticator(){   // 验账账户 

        public PasswordAuthentication getPasswordAuthentication() { 

          return new PasswordAuthentication(username, password); 

        }            

 });

    session.setDebug(true); // 输出跟踪日志

    // 创建 Transport 对象

    transport = session.getTransport();           

  }

  public void sendMessage()throws Exception{

    // 创建一个邮件

    //Message msg = TextMessage.generate();

    //Message msg = HtmlMessage.generate();

    Message msg = AttachmentMessage.generate();

    // 发送邮件    

    transport.connect();

    transport.sendMessage(msg, msg.getAllRecipients());

    // 打印结果

    System.out.println("邮件已经成功发送");

  } 

  public void close()throws Exception

  {

    transport.close();

  }

  public static void main(String[] args)throws Exception {

    MailClientSend client=new MailClientSend();

    // 初始化

    client.init();

    // 发送邮件

    client.sendMessage();

    // 关闭连接

    client.close();

  }

}

//Text

String from = "lychen@sei.ecnu.edu.cn "; // 发件人地址

String to = "chenliangyu1980@126.com"; // 收件人地址

String subject = "test";

String body = "您好,这是来自一封chenliangyu的测试邮件";

// 创建 Session 实例对象

Session session = Session.getDefaultInstance(new Properties());

// 创建 MimeMessage 实例对象

MimeMessage message = new MimeMessage(session);

// 设置发件人

message.setFrom(new InternetAddress(from));

// 设置收件人

message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to));

// 设置发送日期

message.setSentDate(new Date());

// 设置邮件主题

message.setSubject(subject);

// 设置纯文本内容的邮件正文

message.setText(body);

// 保存并生成最终的邮件内容

message.saveChanges();

return message;

//Html

String from = "lychen@sei.ecnu.edu.cn "; // 发件人地址

String to = "chenliangyu1980@126.com"; // 收件人地址

String subject = "HTML邮件";

String body = "<a href=http://www.ecnu.edu.cn>" 

  + "<h4>欢迎大家访问我们的网站</h4></a></br>" 

  + "<img src=\"https://news.ecnu.edu.cn/_upload/article/images/2e/e2/6b554d034c9192101208c732195e/16a6ec66-6729-4469-a5f4-0435e0f2e66a.jpg\">";

// 创建 Session 实例对象

Session session = Session.getDefaultInstance(new Properties());

// 创建 MimeMessage 实例对象

MimeMessage message = new MimeMessage(session);

// 设置发件人

message.setFrom(new InternetAddress(from));

// 设置收件人

message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to));

// 设置发送日期

message.setSentDate(new Date());

// 设置邮件主题

message.setSubject(subject);

// 设置 HTML 格式的邮件正文

message.setContent(body, "text/html;charset=gb2312");

// 保存并生成最终的邮件内容

message.saveChanges();

return message;

//Attachment

String from = "lychen@sei.ecnu.edu.cn "; // 发件人地址

String to = "chenliangyu1980@126.com"; // 收件人地址

String subject = "多附件邮件";        // 邮件主题

String body = "<a href=http://www.ecnu.edu.cn>" +

              "欢迎大家访问我们的网站</a></br>"; 

// 创建 Session 实例对象

Session session = Session.getDefaultInstance(new Properties());

// 创建 MimeMessage 实例对象

MimeMessage message = new MimeMessage(session);            

message.setFrom(new InternetAddress(from));

message.setRecipients(Message.RecipientType.TO,

        InternetAddress.parse(to));

message.setSubject(subject);

// 创建代表邮件正文和附件的各个 MimeBodyPart 对象

MimeBodyPart contentPart = createContent(body);

MimeBodyPart attachPart1 = createAttachment("c:/temp/ecnu4.jpg");

MimeBodyPart attachPart2 = createAttachment("c:/temp/ecnu5.jpg");

// 创建用于组合邮件正文和附件的 MimeMultipart 对象

MimeMultipart allMultipart = new MimeMultipart("mixed");

allMultipart.addBodyPart(contentPart);

allMultipart.addBodyPart(attachPart1);

allMultipart.addBodyPart(attachPart2);

// 设置整个邮件内容为最终组合出的 MimeMultipart 对象

message.setContent(allMultipart);

message.saveChanges();

return message;

public static MimeBodyPart createContent(String body) throws Exception {

    MimeBodyPart htmlBodyPart = new MimeBodyPart();          

    htmlBodyPart.setContent(body,"text/html;charset=gb2312");

    return htmlBodyPart;

}

public static MimeBodyPart createAttachment(String filename) throws Exception {

    // 创建保存附件的 MimeBodyPart 对象，并加入附件内容和相应信息

    MimeBodyPart attachPart = new MimeBodyPart();

    FileDataSource fds = new FileDataSource(filename);

    attachPart.setDataHandler(new DataHandler(fds));

    attachPart.setFileName(fds.getName());

    return attachPart;

}