java |bytebuffer 黏包和半包

黏包和半包讲解。

引入自写的方法类。

下载 JAVA 文件

netty 包

<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-all</artifactId>
    <version>4.1.86.Final</version>
</dependency>

现象

• 黏包
  • 字段 「通过 \n 进行数据分隔」
    • How are you?\n
    • I am rhino\n
  • 网络传输中变成了下面两个 ByteBuffer
    • How are
    • you?\n I am
    • rhino\n
• 半包
  • 服务器缓冲区大小限制

解决

将混乱的数据恢复成 \n 分隔的数据。

package com.redisc;

import lombok.extern.slf4j.Slf4j;

import java.nio.ByteBuffer;

import static com.redisc.ByteBufferUtil.debugAll;

@Slf4j(topic = "c.Test")
public class Run {

    public static void main(String[] args) {
        ByteBuffer source = ByteBuffer.allocate(32);

        source.put("Hello world\nI'm rhino\nH".getBytes());
        split(source);
        source.put("ow are you?\n".getBytes());
        split(source);
    }

    private static void split(ByteBuffer source) {
        // 读模式
        source.flip();
        for (int i = 0; i < source.limit(); i++) {
            if (source.get(i) == '\n') {
                int length = i + 1 - source.position();// 一条消息的长度
                ByteBuffer target = ByteBuffer.allocate(length);
                // 从 source 读，向 target 写
                for (int j = 0; j < length; j++) {
                    target.put(source.get());
                }
                debugAll(target);
            }
        }
        // 写模式
        source.compact();
    }
}

输出

+--------+-------------------- all ------------------------+----------------+
position: [12], limit: [12]
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 48 65 6c 6c 6f 20 77 6f 72 6c 64 0a             |Hello world.    |
+--------+-------------------------------------------------+----------------+
+--------+-------------------- all ------------------------+----------------+
position: [10], limit: [10]
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 49 27 6d 20 72 68 69 6e 6f 0a                   |I'm rhino.      |
+--------+-------------------------------------------------+----------------+
+--------+-------------------- all ------------------------+----------------+
position: [13], limit: [13]
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 48 6f 77 20 61 72 65 20 79 6f 75 3f 0a          |How are you?.   |
+--------+-------------------------------------------------+----------------+