Netty学习之六—— 编解码技术性能对比

1、Java序列化的缺点

1、无法跨语言；

2、序列化后的码流太大；

测试代码如下：

package com.netty.pojo;

import java.io.Serializable;
import java.nio.ByteBuffer;

public class User implements Serializable{

    private static final long serialVersionUID = 1L;

    private String name;

    private int id;

    public User buildName(String name) {
        this.name = name;
        return this;
    }

    public User buildId(int id) {
        this.id = id;
        return this;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    /**
     * 运用 ByteBuffer 的二进制编解码技术对 User 对象进行编码
     * @return
     */
    public byte[] codeC(ByteBuffer buffer) {
        buffer.clear();
        byte[] value = this.name.getBytes();
        buffer.putInt(value.length);
        buffer.put(value);
        buffer.putInt(this.id);
        buffer.flip();
        value = null;
        byte[] result = new byte[buffer.remaining()];
        buffer.get(result);
        return result;
    }
}

package com.netty.codec;

import com.netty.pojo.User;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.nio.ByteBuffer;

public class TestUser {
    public static void main(String[] args) throws IOException {
        User u = new User();
        u.buildId(100).buildName("Welcome to Netty");
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        ObjectOutputStream os = new ObjectOutputStream(out);
        os.writeObject(u);
        os.flush();
        os.close();
        byte[] b = out.toByteArray();
        System.out.println("The jdk serializable length is : " + b.length);
        out.close();
        System.out.println("-----------------------------------------");
        ByteBuffer buffer = ByteBuffer.allocate(1024);
        System.out.println("The ByteBuffer serializable length is : " + u.codeC(buffer).length);
    }
}

运行结果：

jdk编码是 二进制编码方式的 4倍。

3、序列化性能太低；

测试代码如下：

package com.netty.codec;

import com.netty.pojo.User;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.nio.ByteBuffer;

public class PerformTestUser {
    public static void main(String[] args) throws IOException {
        User u = new User();
        u.buildId(100).buildName("Welcome to Netty");
        int loop = 100_0000;
        ByteArrayOutputStream out;
        ObjectOutputStream os;
        long startTime = System.currentTimeMillis();
        for (int i = 0; i < loop; i++) {
            out = new ByteArrayOutputStream();
            os = new ObjectOutputStream(out);
            os.writeObject(u);
            os.flush();
            os.close();
            byte[] b = out.toByteArray();
            out.close();
        }
        long endTime = System.currentTimeMillis();
        System.out.println("The jdk serializable cost time is : " + (endTime - startTime) + " ms");
        System.out.println("-----------------------------------------");
        startTime = System.currentTimeMillis();
        ByteBuffer buffer = ByteBuffer.allocate(1024);
        for (int i=0;i<loop;i++) {
            byte[] b = u.codeC(buffer);
        }
        endTime = System.currentTimeMillis();
        System.out.println("The ByteBuffer serializable  cost time is : " + (endTime - startTime) + " ms");
    }
}

运行结果：

结果很明显，jdk编码速度很差。

2、业界主流的编解码框架

1、Google的 Protobuf

2、Facebook 的 Thrift

3、JBoss Marshalling