java netty socket实例：报文长度+报文内容，springboot

前言

说实话，java netty方面的资料不算多，尤其是自定义报文格式的，少之又少

自己写了个简单的收发：报文长度+报文内容

发送的话，没有写自动组装格式，自己看需求吧，需要的话，自己完善

服务端启动

可以直接用类文件启动，也可以通过springboot。我这里写的是用springboot启动的，可以自己按照需求自己修改

代码

入口

package cn.daenx.demo.example.socket;

import cn.daenx.demo.example.service.BankServerService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;

/**
 * 入口
 *
 * @author DaenMax
 */
@Slf4j
@Component
public class SocketServer {
    /**
     * 这里仅仅是为了注入一个处理消息的service接口
     */
    @Resource
    private BankServerService bankServerService;

    @PostConstruct
    public void start() {
        SocketServerThread socketServerThread = new SocketServerThread(bankServerService);
        socketServerThread.start();
    }

}

服务端

package cn.daenx.demo.example.socket;

import cn.daenx.demo.example.service.BankServerService;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import javax.annotation.PreDestroy;

/**
 * 服务端
 *
 * @author DaenMax
 */
@Slf4j
@Component
public class SocketServerThread extends Thread {
    private static BankServerService bankServerService;

    public SocketServerThread(BankServerService bankServerService) {
        this.bankServerService = bankServerService;
    }

    //监听IP
    private static final String ip = "127.0.0.1";
    //监听端口
    private static final int port = 6666;
    //发送的数据帧最大长度
    private static final int maxFrameLength = Integer.MAX_VALUE;
    //定义长度域位于发送的字节数组中的下标
    private static final int lengthFieldOffset = 0;
    //用于描述定义的长度域的长度默认只支持 1, 2, 3, 4, or 8（原版）
    //我这里重写了解码器，所以支持传入任意长度
    private static final int lengthFieldLength = 6;
    //偏移位，即：长度字节和内容中间隔了几个字节
    private static final int lengthAdjustment = 0;
    //表示获取完一个完整的数据包之后，忽略前面的几个字节
    private static final int initialBytesToStrip = 6;
    private static final EventLoopGroup bossGroup = new NioEventLoopGroup();
    private static final EventLoopGroup workerGroup = new NioEventLoopGroup();

    @Override
    public void run() {
        log.info("SocketServer启动中...");
        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new ChannelInitializer<Channel>() {
                        protected void initChannel(Channel ch) {
                            ChannelPipeline pipeline = ch.pipeline();
                            ch.pipeline().addLast(new CustomLengthFieldDecoder(maxFrameLength, lengthFieldOffset, lengthFieldLength, lengthAdjustment, initialBytesToStrip));
                            pipeline.addLast(new SocketHandler(bankServerService));
                        }
                    });
            ChannelFuture channelFuture = serverBootstrap.bind(ip, port).sync();
            log.info("SocketServer启动完成，端口：" + port);
            channelFuture.channel().closeFuture().sync();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @PreDestroy
    public void preDestroy() {
        log.info("springboot项目即将停止运行");
        workerGroup.shutdownGracefully();
        bossGroup.shutdownGracefully();
        log.info("SocketServer已停止，端口：" + port);
    }
}

事件处理器

package cn.daenx.demo.example.socket;

import cn.daenx.demo.example.service.BankServerService;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import lombok.extern.slf4j.Slf4j;

/**
 * 事件处理器
 *
 * @author DaenMax
 */
@Slf4j
public class SocketHandler extends ChannelInboundHandlerAdapter {

    private final BankServerService bankServerService;

    public SocketHandler(BankServerService bankServerService) {
        this.bankServerService = bankServerService;
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
    }

    /**
     * 接收到的报文
     * 注意，因为用了LengthFieldBasedFrameDecoder，所以这里不会分包，而是会一次性接收完成后才会调用此方法
     *
     * @param ctx
     * @param msg
     */
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) {
        ByteBuf message = (ByteBuf) msg;
        byte[] response = new byte[message.readableBytes()];
        message.readBytes(response);
        String reqStr = new String(response);
        log.info("接收socket->>>" + reqStr);
        String resStr = bankServerService.handleReqXml(reqStr);
        ByteBuf sendMsg = Unpooled.buffer(resStr.length());
        sendMsg.writeBytes(resStr.getBytes());
        ctx.writeAndFlush(sendMsg);
        log.info("响应socket->>>" + resStr);
    }

    /**
     * 发生异常时
     *
     * @param ctx
     * @param cause
     * @throws Exception
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        String resStr = "出现错误，请联系运维人员";
        ByteBuf sendMsg = Unpooled.buffer(resStr.length());
        sendMsg.writeBytes(resStr.getBytes());
        ctx.writeAndFlush(sendMsg);
        log.info("响应socket->>>" + resStr);
        ctx.close();
    }

    /**
     * 获取IP地址
     */
    private String getIP(ChannelHandlerContext ctx) {
        String socketString = ctx.channel().remoteAddress().toString();
        int index = socketString.indexOf(":");
        String ip = socketString.substring(1, index);
        return ip;
    }

}

自定义定长解码器

package cn.daenx.demo.example.socket;

import cn.hutool.core.util.CharsetUtil;
import io.netty.buffer.ByteBuf;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.TooLongFrameException;

import java.nio.ByteOrder;

/**
 * LengthFieldBasedFrameDecoder长度域的长度默认只支持 1, 2, 3, 4, or 8
 * 但是我的需求是6位长度域，所以继承重写getUnadjustedFrameLength方法
 *
 * @author DaenMax
 */
public class CustomLengthFieldDecoder extends LengthFieldBasedFrameDecoder {

    /**
     * Creates a new instance.
     *
     * @param maxFrameLength      the maximum length of the frame.  If the length of the frame is
     *                            greater than this value, {@link TooLongFrameException} will be
     *                            thrown.
     * @param lengthFieldOffset   the offset of the length field
     * @param lengthFieldLength   the length of the length field
     * @param lengthAdjustment    the compensation value to add to the value of the length field
     * @param initialBytesToStrip
     */
    public CustomLengthFieldDecoder(int maxFrameLength, int lengthFieldOffset, int lengthFieldLength, int lengthAdjustment, int initialBytesToStrip) {
        super(maxFrameLength, lengthFieldOffset, lengthFieldLength, lengthAdjustment, initialBytesToStrip);
    }

    /**
     * 重写getUnadjustedFrameLength方法，可以自定义长度区域字节数
     *
     * @param buf
     * @param offset
     * @param length
     * @param order
     * @return
     */
    @Override
    protected long getUnadjustedFrameLength(ByteBuf buf, int offset, int length, ByteOrder order) {
        buf = buf.order(order);
        CharSequence frameLength = buf.getCharSequence(0, length, CharsetUtil.CHARSET_UTF_8);
        Long lengthLength = Long.valueOf((String) frameLength);
        return lengthLength.longValue();
    }
}

service接口

package cn.daenx.demo.example.service.impl;

import cn.daenx.demo.example.service.BankServerService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

/**
 * 处理Socket请求
 *
 * @author DaenMax
 */
@Slf4j
@Service
public class BankServerServiceImpl implements BankServerService {

    /**
     * 处理Socket请求
     *
     * @param str
     * @return
     */
    @Override
    public String handleReqXml(String str) {
        return "我已成功收到你的请求";

    }

}

发送接收方法testSocketSend

package cn.daenx.demo.example.socket;

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

/**
 * 测试发送和接收
 *
 * @author DaenMax
 */
public class testSocketSend {
    //测试发送和接收
    public static void main(String[] args) throws Exception {
        System.out.println(send("127.0.0.1", "6666", "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"));
    }

    /**
     * 发送消息到指定服务上
     *
     * @param host
     * @param port
     * @param msg
     * @return
     */
    public static String send(String host, String port, String msg) throws Exception {
        try (Socket socket = new Socket(host, Integer.parseInt(port));) {
            OutputStream outputStream = socket.getOutputStream();
            PrintWriter printWriter = new PrintWriter(outputStream);
            printWriter.print(msg);
            printWriter.flush();
            socket.shutdownOutput();
            System.out.println("socket发送，host=" + host + "，port=" + port + "，msg=" + msg);
            //获取一个输入流，接收服务端的信息
            InputStream inputStream = socket.getInputStream();
            //包装成字符流，提高效率
            InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
            //缓冲区
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
            StringBuffer sb = new StringBuffer();
            //临时变量
            String temp = null;
            while ((temp = bufferedReader.readLine()) != null) {
                sb.append(temp).append("\n");
            }
            System.out.println("socket接收，host=" + host + "，port=" + port + "，msg=" + sb.toString());
            //关闭相对应的资源
            bufferedReader.close();
            inputStream.close();
            printWriter.close();
            outputStream.close();
            socket.close();
            String ret = sb.toString();
            return ret;
        } catch (IOException e) {
            throw new Exception("连接服务失败");
        }
    }
}

测试

先启动springboot

然后直接运行testSocketSend即可看到效果