久久久久亚洲AV成人网,yy6080久久亚洲精品,亚洲色图在线播放

Chan Chen — Tue, 27 Nov 2012 03:34:00 GMT

摘要: Netty 4.0的源码结构与之前�?.X版本发生了较大的变化�Q�以下是Netty 4.0源码的层�ơ结�? netty/ common/ - utility and logging buffer/ - buffer API ... 阅读全文

Chan Chen 2012-11-27 11:34 发表评论

Chan Chen — Mon, 26 Nov 2012 02:57:00 GMT

AbstractBootstrap是一个帮助类�Q�通过�Ҏ��链（method chaining�Q�的方式�Q�提供了一个简单易用的方式来配�|?/span>Bootstrap�Q�然后启动一�?/span>Channel。在理解Netty源码中的AbstractBootstrap�Q?/span> ServerBootstrap�?/span>Bootstrap之前�Q�应该先了解一下什么是method chaining�?br />

Wiki上面对于method chaining的定义如下：

Method chaining, is a common technique for invoking multiple method calls in object-oriented programming languages. Each method returns an object (possibly the current object itself), allowing the calls to be chained together in a single statement.

在面向对象的�~�程语言中，method chaining是一�U�用于调用多个方法的常用技术。每个方法都会返回一个对象（可能是当前对象本�w�）�Q�这样做的好处就是，通过一条语句，��可以讲所有的�Ҏ��调用链接在一赗��?/span>

定义有一些抽象，那么可以通过实际的例子来�q�行理解和消化�?/span>

假设有一�?/span>StringBuffer的类�Q�类中有一�?/span>append()�Ҏ��

public class StringBuffer {
  public void append(String str) {
    //  useful code
  }
}

�q�个�c�L��~�点��是��_��在向StringBuffer对象�q�加新的字符串的时候，需要在多条语句中，不断的调�?/span>append()�Ҏ��?/span>

StringBuffer sb = new StringBuffer();
sb.append("Hello ");
sb.append(name);
sb.append("! Welcome!");

�?/span>method chaining的实玎ͼ��可以避免这个缺陗��?/span>

public class StringBuffer {
  public StringBuffer append(String str) {
    //  useful code 
    return this;
  }
}

现在我们��可以再一条语句中实现�W�一个例子的功能了�?/span>

StringBuffer sb = new StringBuffer();
sb.append("Hello ").append(name).append("! Welcome!");

AbstractBootstrap抽象�c?/span> �Q�部分代码）

package io.netty.bootstrap;

public abstract class AbstractBootstrapextends AbstractBootstrap> {
    private EventLoopGroup group;
    private ChannelFactory factory;
    private SocketAddress localAddress;
    private final Map, Object> options = new LinkedHashMap, Object>();
    private final Map, Object> attrs = new LinkedHashMap, Object>();
private ChannelHandler handler;

    @SuppressWarnings("unchecked")
    public B group(EventLoopGroup group) {
        if (group == null) {
            throw new NullPointerException("group");
        }
        if (this.group != null) {
            throw new IllegalStateException("group set already");
        }
        this.group = group;
        return (B) this;
    }
    public B channel(Classextends Channel> channelClass) {
        if (channelClass == null) {
            throw new NullPointerException("channelClass");
        }
        return channelFactory(new BootstrapChannelFactory(channelClass));
    }
    @SuppressWarnings("unchecked")
    public B channelFactory(ChannelFactory factory) {
        if (factory == null) {
            throw new NullPointerException("factory");
        }
        if (this.factory != null) {
            throw new IllegalStateException("factory set already");
        }
        this.factory = factory;
        return (B) this;
    }
    @SuppressWarnings("unchecked")
    public B localAddress(SocketAddress localAddress) {
        this.localAddress = localAddress;
        return (B) this;
    }
    @SuppressWarnings("unchecked")
    public  B option(ChannelOption option, T value) {
        if (option == null) {
            throw new NullPointerException("option");
        }
        if (value == null) {
            options.remove(option);
        } else {
            options.put(option, value);
        }
        return (B) this;
    }
    public  B attr(AttributeKey key, T value) {
        if (key == null) {
            throw new NullPointerException("key");
        }
        if (value == null) {
            attrs.remove(key);
        } else {
            attrs.put(key, value);
        }
        return (B) this;
    }
    @SuppressWarnings("unchecked")
    public B handler(ChannelHandler handler) {
        if (handler == null) {
            throw new NullPointerException("handler");
        }
        this.handler = handler;
        return (B) this;
}
}

AbstractBootstrap声明了六个私有的成员变量�Q?/span>EventLoopGroup对象�Q?/span>ChannelFacotry对象�Q?/span>SockteAddress对象�Q?/span>Map,Object>对象�Q?/span>Map,Object>对象�Q?/span>ChannelHandler对象。�ƈ且有相对应的�Ҏ��Q�来讄��q�些对象�Q�如

public B group(EventLoopGroup group) {
        if (group == null) {
            throw new NullPointerException("group");
        }
        if (this.group != null) {
            throw new IllegalStateException("group set already");
        }
        this.group = group;
        return (B) this;
}

通过传进来的group对象�Q�然后将AbstractBootstrap中的group指向传进来的group。最�l�返回的�q�是AbstractBootstrap�q�个当前对象�?/span>

六个对象的作�?/span>

EventLoopGroup group	用于处理��要被创建的所�?/span>event
ChannelFactory factory	建立一个工厂，用于以后�?/span>Channel创徏
SocketAddress localAddress;	用于�l�定本地的网�l�地址
Map, Object> options	指定所创徏Channel的选项�Q�如TCP_NODELAY�Q?/span>AIO_READ_TIMEOUT
Map, Object> attrs	指定所创徏Channel的属�?/span>
ChannelHandler handler	用于处理各类��h��

AbstractBootstrap抽象�cȝ��接口

AbstractBootstrap抽象�c?/span>UML�?/span>

ServerBootstrap�?/span>Bootstrap

�?/span>Netty 4.0中，ServerBootstrap用于为服务器启动ServerChannel�Q?/span>Bootstrap用于为客服端启动Channel。这两个�c�L��AbstractBootstrap的具体实现�?br />

备注:因�ؓ�W�者开始写Netty源码分析的时候，Netty 4.0�q�是处于Alpha阶段�Q�之后的API可能�q�会有改动，�W�者将会及时更攏V��用开源已�l�有好几�q�的旉��了，一直没有时间和�_�֊�来具体研�I�某个开源项目的具体实现�Q�这�ơ是�W�一�ơ写开源项目的源码分析�Q�如果文中有错误的地方，�Ƣ迎读者可以留�a�指出。对于�{载的读者，��h��明文章的出处�?/div>

希望和广大的开发�?开源爱好者进行交��，�Ƣ迎大家的留�a�和讨论�?/div>

Chan Chen 2012-11-26 10:57 发表评论

Netty 4.0 源码分析�Q�六�Q�：EventLoop和EventLoopGroup

Chan Chen — Sun, 25 Nov 2012 13:49:00 GMT

EventLoop相当于一�?/span>Thread�U�程�Q��?/span>EventLoopGroup则是��理�q�些EventLoop�?/span>Thread�U�程�?/span>

EventLoop接口

package io.netty.channel;

public interface EventLoop extends EventExecutor, EventLoopGroup {
@Override
EventLoopGroup parent();
}

EventLoop接口UML�?/span>

parent()�Ҏ��

�q�回��理�q�个EventLoop�?/span>EventLoopGroup�?/span>

EventLoopGroup接口

package io.netty.channel;
public interface EventLoopGroup extends EventExecutorGroup {
    @Override
    EventLoop next();
    ChannelFuture register(Channel channel);
    ChannelFuture register(Channel channel, ChannelFuture future);
}

EventLoopGroup接口UML�?/span>

next()

�q�回下一�?/span>EventLoop

register(Channel channel)

指定一�?/span>EventLoopGroup来注册某�?/span>Channel�?br />

希望和广大的开发�?开源爱好者进行交��，�Ƣ迎大家的留�a�和讨论�?/div>

Chan Chen 2012-11-25 21:49 发表评论

Netty 4.0 源码分析�Q�四�Q�：ByteBuf

Chan Chen — Sun, 25 Nov 2012 12:44:00 GMT

Netty是基于流的消息传递机制�?/span>Netty框架中，所有消息的传输都依赖于ByteBuf接口�Q?/span>ByteBuf�?/span>Netty NIO框架中的�~�冲区�?/span>ByteBuf接口可以理解��Z��般的Byte数组�Q�不�q?/span>Netty�?/span>Byte�q�行了封装，增加了一些实用的�Ҏ��?/span>

ChannelBuf接口

package io.netty.buffer;
public interface ChannelBuf {
ChannelBufType type();
boolean isPooled();
}

ByteBuf接口

package io.netty.buffer;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.GatheringByteChannel;
import java.nio.channels.ScatteringByteChannel;
import java.nio.charset.Charset;
import java.nio.charset.UnsupportedCharsetException;
public interface ByteBuf extends ChannelBuf, Comparable {
    int capacity();
    ByteBuf capacity(int newCapacity);
    int maxCapacity();
    ByteOrder order();
    ByteBuf order(ByteOrder endianness);
    boolean isDirect();
    int readerIndex();
    ByteBuf readerIndex(int readerIndex);
    int writerIndex();
    ByteBuf writerIndex(int writerIndex);
    ByteBuf setIndex(int readerIndex, int writerIndex);
    int readableBytes();
    int writableBytes();
    boolean readable();
    boolean writable();
    ByteBuf clear();
    ByteBuf markReaderIndex();
    ByteBuf resetReaderIndex();
    ByteBuf markWriterIndex();
    ByteBuf resetWriterIndex();
    ByteBuf discardReadBytes();
    ByteBuf ensureWritableBytes(int minWritableBytes);
    int ensureWritableBytes(int minWritableBytes, boolean force);
    boolean getBoolean(int index);
    byte  getByte(int index);
    short getUnsignedByte(int index);
    short getShort(int index);
    int getUnsignedShort(int index);
    int   getMedium(int index);
    int   getUnsignedMedium(int index);
    int   getInt(int index);
    long  getUnsignedInt(int index);
    long  getLong(int index);
    char  getChar(int index);
    float getFloat(int index);
    double getDouble(int index);
    ByteBuf getBytes(int index, ByteBuf dst);
    ByteBuf getBytes(int index, ByteBuf dst, int length);
    ByteBuf getBytes(int index, ByteBuf dst, int dstIndex, int length);
    ByteBuf getBytes(int index, byte[] dst);
    ByteBuf getBytes(int index, byte[] dst, int dstIndex, int length);
    ByteBuf getBytes(int index, ByteBuffer dst);
    ByteBuf getBytes(int index, OutputStream out, int length) throws IOException;
    int getBytes(int index, GatheringByteChannel out, int length) throws IOException;
    ByteBuf setBoolean(int index, boolean value);
    ByteBuf setByte(int index, int value);
    ByteBuf setShort(int index, int value);
    ByteBuf setMedium(int index, int   value);
    ByteBuf setInt(int index, int   value);
    ByteBuf setLong(int index, long  value);
    ByteBuf setChar(int index, int value);
    ByteBuf setFloat(int index, float value);
    ByteBuf setDouble(int index, double value);
    ByteBuf setBytes(int index, ByteBuf src);
    ByteBuf setBytes(int index, ByteBuf src, int length);
    ByteBuf setBytes(int index, ByteBuf src, int srcIndex, int length);
    ByteBuf setBytes(int index, byte[] src);
    ByteBuf setBytes(int index, byte[] src, int srcIndex, int length);
    ByteBuf setBytes(int index, ByteBuffer src);
    int setBytes(int index, InputStream in, int length) throws IOException;
    int  setBytes(int index, ScatteringByteChannel in, int length) throws IOException;
    ByteBuf setZero(int index, int length);
     boolean readBoolean();
    byte  readByte();
    short readUnsignedByte();
    short readShort();
    int   readUnsignedShort();
    int   readMedium();
    int   readUnsignedMedium();
    int   readInt();
    long  readUnsignedInt();
    long  readLong();
    char  readChar();
    float readFloat();
    double readDouble();
    ByteBuf readBytes(int length);
    ByteBuf readSlice(int length);
    ByteBuf readBytes(ByteBuf dst);
    ByteBuf readBytes(ByteBuf dst, int length);
    ByteBuf readBytes(ByteBuf dst, int dstIndex, int length);
    ByteBuf readBytes(byte[] dst);
    ByteBuf readBytes(byte[] dst, int dstIndex, int length);
    ByteBuf readBytes(ByteBuffer dst);
    ByteBuf readBytes(OutputStream out, int length) throws IOException;
    int  readBytes(GatheringByteChannel out, int length) throws IOException;
    ByteBuf skipBytes(int length);
    ByteBuf writeBoolean(boolean value);
    ByteBuf writeByte(int value);
    ByteBuf writeShort(int value);
    ByteBuf writeMedium(int   value);
    ByteBuf writeInt(int   value);
    ByteBuf writeLong(long  value);
    ByteBuf writeChar(int value);
    ByteBuf writeFloat(float value);
    ByteBuf writeDouble(double value);
    ByteBuf writeBytes(ByteBuf src);
    ByteBuf writeBytes(ByteBuf src, int length);
    ByteBuf writeBytes(ByteBuf src, int srcIndex, int length);
    ByteBuf writeBytes(byte[] src);
    ByteBuf writeBytes(byte[] src, int srcIndex, int length);
    ByteBuf writeBytes(ByteBuffer src);
    int  writeBytes(InputStream in, int length) throws IOException;
    int  writeBytes(ScatteringByteChannel in, int length) throws IOException;
    ByteBuf writeZero(int length);
    int indexOf(int fromIndex, int toIndex, byte value);
    int indexOf(int fromIndex, int toIndex, ByteBufIndexFinder indexFinder);
    int bytesBefore(byte value);
    int bytesBefore(ByteBufIndexFinder indexFinder);
    int bytesBefore(int length, byte value);
    int bytesBefore(int length, ByteBufIndexFinder indexFinder);
    int bytesBefore(int index, int length, byte value);
    int bytesBefore(int index, int length, ByteBufIndexFinder indexFinder);
    ByteBuf copy();
    ByteBuf copy(int index, int length);
    ByteBuf slice();
    ByteBuf slice(int index, int length);
    ByteBuf duplicate();
    boolean hasNioBuffer();
    ByteBuffer nioBuffer();
    ByteBuffer nioBuffer(int index, int length);
    boolean hasNioBuffers();
    ByteBuffer[] nioBuffers();
    ByteBuffer[] nioBuffers(int offset, int length);
    boolean hasArray();
    byte[] array();
    int arrayOffset();
    String toString(Charset charset);
    String toString(int index, int length, Charset charset);
    @Override
    int hashCode();
    @Override
    boolean equals(Object obj);
    @Override
    int compareTo(ByteBuf buffer);
    @Override
    String toString();
    Unsafe unsafe();
    interface Unsafe {
        ByteBuffer nioBuffer();
        ByteBuffer[] nioBuffers();
        ByteBuf newBuffer(int initialCapacity);
        void discardSomeReadBytes();
        void acquire();
        void release();
    }
}

ByteBuf Index

ByteBuf通过两个指针来协�?/span>I/O的读写操作，��L��作的readIndex和写操作�?/span>writeIndex

readerIndex�?/span>writerIndex都是一开始都�?/span>0�Q�随着数据的写�?/span>writerIndex会增加，��d��数据会��readerIndex增加�Q�但是他不会��过writerIndx�Q�在��d��之后�Q?/span>0-readerIndex的就被视�?/span>discard�?/span>.调用discardReadBytes�Ҏ��,可以释放�q�部分空�?/span>,他的作用�c�M��ByeBuffer�?/span>compact�Ҏ��;

��d��写的时�?/span>Index是分开的，因此也就没必要再每次��d��以后调用flip�Ҏ��Q�另外还�?/span>indexOf�?/span>bytesBefore�{�一些方便的�Ҏ��Q?/span>

ByteBuf的几个重要方�?/span>

discardReadBytes()
丢弃已读的内宏V��其执行�q�程如下�Q?/span>
调用discardReadBytes()之前�Q?/span>

调用 discardReadBytes()�Ҏ��?/span>

clear()
丢弃所有的数据�Q��ƈ��?span style="font-size: 6.5pt; font-family: 'Courier New'; background-position: initial initial; background-repeat: initial initial;">readerIndex�?/span>writerIndex重置�?/span>0�?/span>

调用clear()之前

调用clear()之后

希望和广大的开发�?开源爱好者进行交��，�Ƣ迎大家的留�a�和讨论�?/div>

Chan Chen 2012-11-25 20:44 发表评论

Netty 4.0 源码分析�Q�五�Q�：ChannelHandlerContext和ChannelHandler

Chan Chen — Sun, 25 Nov 2012 08:51:00 GMT

ChannelHandlerContext接口

1 package io.netty.channel;
2 import io.netty.buffer.ByteBuf;
3 import io.netty.buffer.MessageBuf;
4 import io.netty.util.AttributeMap;
5 import java.nio.channels.Channels;
6 import java.util.Set;
7 public interface ChannelHandlerContext
8          extends AttributeMap, ChannelFutureFactory,
9                  ChannelInboundInvoker, ChannelOutboundInvoker {
10     Channel channel();
11     ChannelPipeline pipeline();
12     EventExecutor executor();
13     String name();
14     ChannelHandler handler();
15     Set types();
16     boolean hasInboundByteBuffer();
17     boolean hasInboundMessageBuffer();
18     ByteBuf inboundByteBuffer();
19      MessageBuf inboundMessageBuffer();
20     boolean hasOutboundByteBuffer();
21     boolean hasOutboundMessageBuffer();
22     ByteBuf outboundByteBuffer();
23      MessageBuf outboundMessageBuffer();
24     ByteBuf replaceInboundByteBuffer(ByteBuf newInboundByteBuf);
25      MessageBuf replaceInboundMessageBuffer(MessageBuf newInboundMsgBuf);
26     ByteBuf replaceOutboundByteBuffer(ByteBuf newOutboundByteBuf);
27      MessageBuf replaceOutboundMessageBuffer(MessageBuf newOutboundMsgBuf);
28     boolean hasNextInboundByteBuffer();
29     boolean hasNextInboundMessageBuffer();
30     ByteBuf nextInboundByteBuffer();
31     MessageBuf nextInboundMessageBuffer();
32     boolean hasNextOutboundByteBuffer();
33     boolean hasNextOutboundMessageBuffer();
34     ByteBuf nextOutboundByteBuffer();
35     MessageBuf nextOutboundMessageBuffer();
36     boolean isReadable();
37     void readable(boolean readable);
38 }

ChannelHandlerContext接口UML�c?/span>

ChannelHandlerContext接口的几个重要方�?/span>

ChannelPipeline pipeline();

�q�回属于当前ChannelHandlerContext�?/span>ChannelPipeline�?/span>

EventExecutor executor();

EnventExcutor用于调度EventLoop中的event�Q�这个方法返回当前的EventExecutor�?/span>

一�?/span>Handler可以有多�?/span>Context

一�?/span>Handler可以被添加到多个ChannelPipeline。这��意味着一�?/span>ChannelHandler可以有多�?/span>ChannelHandlerContext�?/span>

ChannelHandler接口

1 package io.netty.channel;
2
3 import io.netty.channel.group.ChannelGroup;
4 import java.lang.annotation.Documented;
5 import java.lang.annotation.ElementType;
6 import java.lang.annotation.Inherited;
7 import java.lang.annotation.Retention;
8 import java.lang.annotation.RetentionPolicy;
9 import java.lang.annotation.Target;
10 import java.nio.channels.Channels;
11
12 public interface ChannelHandler {
13     void beforeAdd(ChannelHandlerContext ctx) throws Exception;
14     void afterAdd(ChannelHandlerContext ctx) throws Exception;
15     void beforeRemove(ChannelHandlerContext ctx) throws Exception;
16     void afterRemove(ChannelHandlerContext ctx) throws Exception;
17     void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception;
18     void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception;
19     @Inherited
20     @Documented
21     @Target(ElementType.TYPE)
22     @Retention(RetentionPolicy.RUNTIME)
23     @interface Sharable {
24         // no value
25     }
26 }

ChannelHandler�c?/span>UML�?/span>

ChannelHandler中的几个重要�Ҏ��

ChannelHandler有两个子接口�Q?/span>ChannelUpstreamHandler�?/span>ChannelDownstreamHandler�?/span>

1. ChannelUpstreamHandler用于处理和拦�?/span>upstream中的ChannelEvent

2. ChannelDownstreamHandler用于处理和拦�?/span>downstream中的ChannelEvent

状态信�?/span>

ChannelHandler一般需要存储一些状态信息，以下是【官�Ҏ��荐】的�Ҏ��Q��用成员变量�?/span>

public class DataServerHandler extends SimpleChannelHandler {
     private boolean loggedIn;
     @Override
     public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) {
         Channel ch = e.getChannel();
         Object o = e.getMessage();
         if (o instanceof LoginMessage) {
             authenticate((LoginMessage) o);
             loggedIn = true;
         } else (o instanceof GetDataMessage) {
             if (loggedIn) {
                 ch.write(fetchSecret((GetDataMessage) o));
             } else {
                 fail();
             }
         }
     }

}

// Create a new handler instance per channel.
// See ClientBootstrap#setPipelineFactory(ChannelPipelineFactory).
public class DataServerPipelineFactory implements ChannelPipelineFactory {
     public ChannelPipeline getPipeline() {
         return Channels.pipeline(new DataServerHandler());
     }
}

或者��?/span>ChannelLocal�Q�代码如�?/span>

public final class DataServerState {
     public static final ChannelLocal loggedIn = new ChannelLocal<>() {
         protected Boolean initialValue(Channel channel) {
             return false;
         }
     }
     
}

 @Sharable
 public class DataServerHandler extends SimpleChannelHandler {
     @Override
     public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) {
         Channel ch = e.getChannel();
         Object o = e.getMessage();
         if (o instanceof LoginMessage) {
             authenticate((LoginMessage) o);
             DataServerState.loggedIn.set(ch, true);
         } else (o instanceof GetDataMessage) {
             if (DataServerState.loggedIn.get(ch)) {
                 ctx.getChannel().write(fetchSecret((GetDataMessage) o));
             } else {
                 fail();
             }
         }
     }
     
}


 // Print the remote addresses of the authenticated clients:
 ChannelGroup allClientChannels = ;
 for (Channel ch: allClientChannels) {
     if (DataServerState.loggedIn.get(ch)) {
         System.out.println(ch.getRemoteAddress());
     }
 }


备注:因�ؓ�W�者开始写Netty源码分析的时候，Netty 4.0�q�是处于Alpha阶段�Q�之后的API可能�q�会有改动，�W�者将会及时更攏V����用开源已�l�有好几�q�的旉���了，一直没有时间和�_�֊�来具体研�I�某个开源项目的具体实现�Q�这�ơ是�W�一�ơ写开源项目的源码分析�Q�如果文中有错误的地方，�Ƣ迎读者可以留�a�指出。对于�{载的读者，��h��明文章的出处�?希望和广大的开发�?开源爱好者进行交���，�Ƣ迎大家的留�a�和讨论�?/div>

Chan Chen 2012-11-25 16:51 发表评论

Netty 4.0 源码分析�Q�三�Q�：Channel和ChannelPipeline

Chan Chen — Sun, 25 Nov 2012 06:53:00 GMT

摘要: Client和server通过Channel�q�接�Q�然后通过ByteBuf�q�行传输。每个Channel有自��q��Pipeline�Q�Pipeline上面可以��d��和定义Handler和Event�? Channel�c?nbsp;1 package io.netty.channel; 2 import io.netty.buffer.Byte... 阅读全文

Chan Chen 2012-11-25 14:53 发表评论

Netty 4.0 源码分析�Q�二�Q�：Echo Server

Chan Chen — Sat, 24 Nov 2012 04:38:00 GMT

Netty��目中，自带了很多��用的例子�Q�对于刚刚开始接触和学习Netty源码的开发者来��_��可以通过例子来更好的理解Netty的具体实现。源码可以再netty 4.0的example扑ֈ��?/span>

1 public class EchoServerHandler extends ChannelInboundByteHandlerAdapter {
2     private static final Logger logger = Logger.getLogger(
3             EchoServerHandler.class.getName());
4
5     @Override
6     public void inboundBufferUpdated(ChannelHandlerContext ctx, ByteBuf in) {
7         ByteBuf out = ctx.nextOutboundByteBuffer();
8         out.discardReadBytes();
9         out.writeBytes(in);
10         ctx.flush();
11     }
12
13     @Override
14     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
15         // Close the connection when an exception is raised.
16         logger.log(Level.WARNING, "Unexpected exception from downstream.", cause);
17         ctx.close();
18     }
19 }

Line 1: 声明一�?/span>EchoServerHandler, �q�且�l�承�?/span>ChannelInboundByteHandlerAdapter�?/span> �q�样EchoServerHandler��可以处�?/span>client发送过来的request�?/span>

Line 6: 重写inboundBufferUpdated�Ҏ��Q�对client发送过来的request�q�行�?/span>ByteBuffer对象的操作。关�?/span>ByteBuffer的概念将在以后章节讨论�?/span>

Line 7: ctx.nextOutboundByteBuffer()��返回一�?/span>ByteBuffer对象。如果该对象不存在，那么抛出UnsupportedOperationException异常�?/span>

Line 14: 重写exceptionCaught�?/span>server端捕获异常�?/span>

1 public class EchoServer {
2
3     private final int port;
4
5     public EchoServer(int port) {
6         this.port = port;
7     }
8
9     public void run() throws Exception {
10         // Configure the server.
11         ServerBootstrap b = new ServerBootstrap();
12         try {
13             b.group(new NioEventLoopGroup(), new NioEventLoopGroup())
14              .channel(NioServerSocketChannel.class)
15              .option(ChannelOption.SO_BACKLOG, 100)
16              .localAddress(new InetSocketAddress(port))
17              .childOption(ChannelOption.TCP_NODELAY, true)
18              .handler(new LoggingHandler(LogLevel.INFO))
19              .childHandler(new ChannelInitializer() {
20                  @Override
21                  public void initChannel(SocketChannel ch) throws Exception {
22                      ch.pipeline().addLast(
23                              new LoggingHandler(LogLevel.INFO),
24                              new EchoServerHandler());
25                  }
26              });
27
28             // Start the server.
29             ChannelFuture f = b.bind().sync();
30
31             // Wait until the server socket is closed.
32             f.channel().closeFuture().sync();
33         } finally {
34             // Shut down all event loops to terminate all threads.
35             b.shutdown();
36         }
37     }
38
39     public static void main(String[] args) throws Exception {
40         int port;
41         if (args.length > 0) {
42             port = Integer.parseInt(args[0]);
43         } else {
44             port = 8080;
45         }
46         new EchoServer(port).run();
47     }
48 }

Line 11: 通过ServerBootStrap对象�Q�来启动服务�?/span>

Line 13: 通过group�Ҏ��Q�来�l�定EventLoopGroup�Q?/span>EventLoopGroup用来处理SocketChannel�?/span>Channel上面的所有时间和IO�?/span>

Line 16: localAddress�Ҏ��用于�l�定服务器地址和端口�?/span>

Line 18,19: handler�Ҏ��?/span>childhandler�Ҏ��用于指定各种ChannelHandler对象�Q�指定的ChannelHandler对象��用于处�?/span>client端来�?/span>request�?/span>

Line 21: 初始化一�?/span>Channel对象�Q��ƈ且绑定之前定义的EchoServerHandler�c�R�?/span>

Line 22: ��?/span>EchoServerHandler��d��?/span>Pipeline中�?/span>

Line 29: ServerBootstrap对象准备��q�A�Q�启�?/span>server�Q?/span>

Line 32: �{�待直到server socket关闭

public class EchoClientHandler extends ChannelInboundByteHandlerAdapter {

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

    private final ByteBuf firstMessage;

    /**
     * Creates a client-side handler.
     */
    public EchoClientHandler(int firstMessageSize) {
        if (firstMessageSize <= 0) {
            throw new IllegalArgumentException("firstMessageSize: " + firstMessageSize);
        }
        firstMessage = Unpooled.buffer(firstMessageSize);
        for (int i = 0; i < firstMessage.capacity(); i ++) {
            firstMessage.writeByte((byte) i);
        }
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        ctx.write(firstMessage);
    }

    @Override
    public void inboundBufferUpdated(ChannelHandlerContext ctx, ByteBuf in) {
        ByteBuf out = ctx.nextOutboundByteBuffer();
        out.discardReadBytes();
        out.writeBytes(in);
        ctx.flush();
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        // Close the connection when an exception is raised.
        logger.log(Level.WARNING, "Unexpected exception from downstream.", cause);
        ctx.close();
    }
}

EchoClientHandler�cȝ��实现�?/span>EchoServerHandler�c�M��Q�也都��承了ChannelInboundByteHandlerAdapter。不同在于重写了channelActive()�Ҏ��?/span>

1 public class EchoClient {
2
3     private final String host;
4     private final int port;
5     private final int firstMessageSize;
6
7     public EchoClient(String host, int port, int firstMessageSize) {
8         this.host = host;
9         this.port = port;
10         this.firstMessageSize = firstMessageSize;
11     }
12
13     public void run() throws Exception {
14         // Configure the client.
15         Bootstrap b = new Bootstrap();
16         try {
17             b.group(new NioEventLoopGroup())
18              .channel(NioSocketChannel.class)
19              .option(ChannelOption.TCP_NODELAY, true)
20              .remoteAddress(new InetSocketAddress(host, port))
21              .handler(new ChannelInitializer() {
22                  @Override
23                  public void initChannel(SocketChannel ch) throws Exception {
24                      ch.pipeline().addLast(
25                              new LoggingHandler(LogLevel.INFO),
26                              new EchoClientHandler(firstMessageSize));
27                  }
28              });
29
30             // Start the client.
31             ChannelFuture f = b.connect().sync();
32
33             // Wait until the connection is closed.
34             f.channel().closeFuture().sync();
35         } finally {
36             // Shut down the event loop to terminate all threads.
37             b.shutdown();
38         }
39     }
40
41     public static void main(String[] args) throws Exception {
42         // Print usage if no argument is specified.
43         if (args.length < 2 || args.length > 3) {
44             System.err.println(
45                     "Usage: " + EchoClient.class.getSimpleName() +
46                     "   []");
47             return;
48         }
49
50         // Parse options.
51         final String host = args[0];
52         final int port = Integer.parseInt(args[1]);
53         final int firstMessageSize;
54         if (args.length == 3) {
55             firstMessageSize = Integer.parseInt(args[2]);
56         } else {
57             firstMessageSize = 256;
58         }
59
60         new EchoClient(host, port, firstMessageSize).run();
61     }
62 }

Line 20: 指定�q�程服务器的地址和端口（localhost:8080�Q?br />

希望和广大的开发�?开源爱好者进行交��，�Ƣ迎大家的留�a�和讨论�?/div>

Chan Chen 2012-11-24 12:38 发表评论

Netty 4.0 源码分析�Q�一�Q�：配置环境

Chan Chen — Thu, 22 Nov 2012 13:21:00 GMT

Netty 源码分析�Q�一�Q�：配置环境
1. 下蝲jdk + elipse + egit
2. 相关jar包下�?br />3. cynwin + telnet/ssh (setup.exe keywork:inetutils / ssh )
3. 从example包开始阅�?br />

希望和广大的开发�?开源爱好者进行交��，�Ƣ迎大家的留�a�和讨论�?/div>

Chan Chen 2012-11-22 21:21 发表评论