利用LineBasedFrameDecoder解决TCP粘包问题

1：TimeServer类

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.LineBasedFrameDecoder;
import io.netty.handler.codec.string.StringDecoder;

public class TimeServer {

public void bind(int port) throws Exception {
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();

try {
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.option(ChannelOption.SO_BACKLOG, 1024)
.childHandler(new ChildChannelHandler());
//绑定端口，同步等待成功
ChannelFuture future = serverBootstrap.bind(port).sync();
//等待服务端监听端口关闭
future.channel().closeFuture().sync();

} catch (Exception e) {
e.printStackTrace();
} finally {
//优雅退出
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}

private class ChildChannelHandler extends ChannelInitializer<SocketChannel> {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
socketChannel.pipeline().addLast(new LineBasedFrameDecoder(1024));
socketChannel.pipeline().addLast(new StringDecoder());
socketChannel.pipeline().addLast(new TimeServerHandler());
}
}

public static void main(String[] args) throws Exception {
int port = 8080;
if (args != null && args.length > 0) {
try {
port = Integer.parseInt(args[0]);
} catch (Exception e) {
e.printStackTrace();
}
}
new TimeServer().bind(port);
}

}

2：TimeServerHandler

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import java.sql.Timestamp;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

public class TimeServerHandler extends ChannelInboundHandlerAdapter {

private int counter = 0;

public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
String body = (String)msg;
System.out.println("The time server receive order : " + body + "; the counter is " + (++this.counter));

String currentTime = "QUERY TIME ORDER".equalsIgnoreCase(body) ? new Date(System.currentTimeMillis()).toString() : "BAD ORDER";

currentTime += System.getProperty("line.separator");

ByteBuf resp = Unpooled.copiedBuffer(currentTime.getBytes());
ctx.writeAndFlush(resp);
}

@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
super.exceptionCaught(ctx, cause);
}
}
3：TimeClient

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.LineBasedFrameDecoder;
import io.netty.handler.codec.string.StringDecoder;

public class TimeClient {

public void connect(int port, String host) throws Exception {
//配置客户端NIO线程组
EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap();

bootstrap.group(eventLoopGroup)
.channel(NioSocketChannel.class)
.option(ChannelOption.SO_BACKLOG, 1024)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
socketChannel.pipeline().addLast(new LineBasedFrameDecoder(1024));
socketChannel.pipeline().addLast(new StringDecoder());
socketChannel.pipeline().addLast(new TimeClientHandler());
}
});

//发起异步链接操作
ChannelFuture channelFuture = bootstrap.connect(host, port).sync();

//等待客户端链路关闭
channelFuture.channel().closeFuture().sync();

} catch (Exception e) {
e.printStackTrace();
} finally {
//优雅退出，释放NIO线程组
eventLoopGroup.shutdownGracefully();
}
}

public static void main(String[] args) throws Exception {
int port = 8080;
if (args != null && args.length > 0) {
try {
port = Integer.parseInt(args[0]);
} catch (Exception e) { //采用默认值
e.printStackTrace();
}
}

new TimeClient().connect(port, "127.0.0.1");
}

}
4：TimeClientHandler

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;

public class TimeClientHandler extends ChannelInboundHandlerAdapter {

private int counter = 0;

private byte[] req;

public TimeClientHandler() {
req = ("QUERY TIME ORDER" + System.getProperty("line.separator")).getBytes();
}

public void channelActive(ChannelHandlerContext ctx) {
ByteBuf message = null;
for (int i = 0; i < 100; i++) {
message = Unpooled.buffer(req.length);
message.writeBytes(req);
ctx.writeAndFlush(message);
}
}

public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
String body = (String)msg;
System.out.println("Now is " + body + "; the counter is " + (++this.counter));
}

@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
super.exceptionCaught(ctx, cause);
}
}


5：测试结果
TimeServer端：

The time server receive order : QUERY TIME ORDER; the counter is 1

The time server receive order : QUERY TIME ORDER; the counter is 2

The time server receive order : QUERY TIME ORDER; the counter is 3

The time server receive order : QUERY TIME ORDER; the counter is 4

The time server receive order : QUERY TIME ORDER; the counter is 5

The time server receive order : QUERY TIME ORDER; the counter is 6

The time server receive order : QUERY TIME ORDER; the counter is 7

The time server receive order : QUERY TIME ORDER; the counter is 8

The time server receive order : QUERY TIME ORDER; the counter is 9

The time server receive order : QUERY TIME ORDER; the counter is 10

The time server receive order : QUERY TIME ORDER; the counter is 11

The time server receive order : QUERY TIME ORDER; the counter is 12

The time server receive order : QUERY TIME ORDER; the counter is 13

The time server receive order : QUERY TIME ORDER; the counter is 14

The time server receive order : QUERY TIME ORDER; the counter is 15

The time server receive order : QUERY TIME ORDER; the counter is 16

The time server receive order : QUERY TIME ORDER; the counter is 17

The time server receive order : QUERY TIME ORDER; the counter is 18

The time server receive order : QUERY TIME ORDER; the counter is 19

The time server receive order : QUERY TIME ORDER; the counter is 20

The time server receive order : QUERY TIME ORDER; the counter is 21

The time server receive order : QUERY TIME ORDER; the counter is 22

The time server receive order : QUERY TIME ORDER; the counter is 23

The time server receive order : QUERY TIME ORDER; the counter is 24

The time server receive order : QUERY TIME ORDER; the counter is 25

The time server receive order : QUERY TIME ORDER; the counter is 26

The time server receive order : QUERY TIME ORDER; the counter is 27

The time server receive order : QUERY TIME ORDER; the counter is 28

The time server receive order : QUERY TIME ORDER; the counter is 29

The time server receive order : QUERY TIME ORDER; the counter is 30

The time server receive order : QUERY TIME ORDER; the counter is 31

The time server receive order : QUERY TIME ORDER; the counter is 32

The time server receive order : QUERY TIME ORDER; the counter is 33

The time server receive order : QUERY TIME ORDER; the counter is 34

The time server receive order : QUERY TIME ORDER; the counter is 35

The time server receive order : QUERY TIME ORDER; the counter is 36

The time server receive order : QUERY TIME ORDER; the counter is 37

The time server receive order : QUERY TIME ORDER; the counter is 38

The time server receive order : QUERY TIME ORDER; the counter is 39

The time server receive order : QUERY TIME ORDER; the counter is 40

The time server receive order : QUERY TIME ORDER; the counter is 41

The time server receive order : QUERY TIME ORDER; the counter is 42

The time server receive order : QUERY TIME ORDER; the counter is 43

The time server receive order : QUERY TIME ORDER; the counter is 44

The time server receive order : QUERY TIME ORDER; the counter is 45

The time server receive order : QUERY TIME ORDER; the counter is 46

The time server receive order : QUERY TIME ORDER; the counter is 47

The time server receive order : QUERY TIME ORDER; the counter is 48

The time server receive order : QUERY TIME ORDER; the counter is 49

The time server receive order : QUERY TIME ORDER; the counter is 50

The time server receive order : QUERY TIME ORDER; the counter is 51

The time server receive order : QUERY TIME ORDER; the counter is 52

The time server receive order : QUERY TIME ORDER; the counter is 53

The time server receive order : QUERY TIME ORDER; the counter is 54

The time server receive order : QUERY TIME ORDER; the counter is 55

The time server receive order : QUERY TIME ORDER; the counter is 56

The time server receive order : QUERY TIME ORDER; the counter is 57

The time server receive order : QUERY TIME ORDER; the counter is 58

The time server receive order : QUERY TIME ORDER; the counter is 59

The time server receive order : QUERY TIME ORDER; the counter is 60

The time server receive order : QUERY TIME ORDER; the counter is 61

The time server receive order : QUERY TIME ORDER; the counter is 62

The time server receive order : QUERY TIME ORDER; the counter is 63

The time server receive order : QUERY TIME ORDER; the counter is 64

The time server receive order : QUERY TIME ORDER; the counter is 65

The time server receive order : QUERY TIME ORDER; the counter is 66

The time server receive order : QUERY TIME ORDER; the counter is 67

The time server receive order : QUERY TIME ORDER; the counter is 68

The time server receive order : QUERY TIME ORDER; the counter is 69

The time server receive order : QUERY TIME ORDER; the counter is 70

The time server receive order : QUERY TIME ORDER; the counter is 71

The time server receive order : QUERY TIME ORDER; the counter is 72

The time server receive order : QUERY TIME ORDER; the counter is 73

The time server receive order : QUERY TIME ORDER; the counter is 74

The time server receive order : QUERY TIME ORDER; the counter is 75

The time server receive order : QUERY TIME ORDER; the counter is 76

The time server receive order : QUERY TIME ORDER; the counter is 77

The time server receive order : QUERY TIME ORDER; the counter is 78

The time server receive order : QUERY TIME ORDER; the counter is 79

The time server receive order : QUERY TIME ORDER; the counter is 80

The time server receive order : QUERY TIME ORDER; the counter is 81

The time server receive order : QUERY TIME ORDER; the counter is 82

The time server receive order : QUERY TIME ORDER; the counter is 83

The time server receive order : QUERY TIME ORDER; the counter is 84

The time server receive order : QUERY TIME ORDER; the counter is 85

The time server receive order : QUERY TIME ORDER; the counter is 86

The time server receive order : QUERY TIME ORDER; the counter is 87

The time server receive order : QUERY TIME ORDER; the counter is 88

The time server receive order : QUERY TIME ORDER; the counter is 89

The time server receive order : QUERY TIME ORDER; the counter is 90

The time server receive order : QUERY TIME ORDER; the counter is 91

The time server receive order : QUERY TIME ORDER; the counter is 92

The time server receive order : QUERY TIME ORDER; the counter is 93

The time server receive order : QUERY TIME ORDER; the counter is 94

The time server receive order : QUERY TIME ORDER; the counter is 95

The time server receive order : QUERY TIME ORDER; the counter is 96

The time server receive order : QUERY TIME ORDER; the counter is 97

The time server receive order : QUERY TIME ORDER; the counter is 98

The time server receive order : QUERY TIME ORDER; the counter is 99

The time server receive order : QUERY TIME ORDER; the counter is 100

TimeClient端：

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 1

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 2

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 3

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 4

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 5

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 6

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 7

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 8

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 9

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 10

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 11

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 12

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 13

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 14

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 15

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 16

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 17

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 18

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 19

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 20

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 21

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 22

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 23

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 24

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 25

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 26

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 27

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 28

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 29

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 30

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 31

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 32

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 33

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 34

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 35

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 36

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 37

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 38

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 39

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 40

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 41

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 42

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 43

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 44

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 45

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 46

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 47

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 48

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 49

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 50

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 51

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 52

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 53

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 54

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 55

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 56

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 57

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 58

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 59

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 60

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 61

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 62

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 63

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 64

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 65

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 66

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 67

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 68

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 69

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 70

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 71

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 72

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 73

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 74

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 75

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 76

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 77

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 78

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 79

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 80

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 81

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 82

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 83

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 84

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 85

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 86

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 87

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 88

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 89

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 90

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 91

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 92

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 93

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 94

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 95

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 96

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 97

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 98

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 99

Now is Mon Jul 10 00:55:19 CST 2017; the counter is 100