This article introduces simple practices for several common serialization protocols

ProtoBuf

1. Download the compiler, protoc protoc-3.11.4-osx-x86_64.zip; download versions of different operating systems. https://github.com/google/protobuf/releases
2. Setting environment variables

 vi ~/.bash_profile
 export PATH=$PATH:/path/to/protoc-3.4.0/bin

1. Introducing dependencies in maven projects

<!-- https://mvnrepository.com/artifact/com.google.protobuf/protobuf-java -->
    <dependency>
      <groupId>com.google.protobuf</groupId>
      <artifactId>protobuf-java</artifactId>
      <version>3.11.4</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/com.googlecode.protobuf-java-format/protobuf-java-format -->
    <dependency>
      <groupId>com.googlecode.protobuf-java-format</groupId>
      <artifactId>protobuf-java-format</artifactId>
      <version>1.4</version>
    </dependency>

1. Write protocol file with extension proto

syntax = "proto2";

package com.seandde.test;

option optimize_for = SPEED;
option java_package = "com.seandde.test.protobuf";
option java_outer_classname = "DataInfo";


message Student {
    required string name =1;
    required int32 age = 2;
    optional string address = 3;

}

1. Generate corresponding java classes using protoc

protoc --java_out=src/main/java src/protobuf/Student.proto

1. Under Simple Test

public class ProtoBufTest {
    public static void main(String ...arg) throws Exception {

        DataInfo.Student student = DataInfo.Student.newBuilder().setName("Zhang San").setAge(28).setAddress("Beijing").build();

        System.out.println(student);

        //Converting to bytes can be transferred over the network
        byte[] stdent2ByteArray = student.toByteArray();

        //Convert to a java object
        DataInfo.Student student2 = DataInfo.Student.parseFrom(stdent2ByteArray);

        System.out.println(student2);

    }

}

Related links: https://developers.google.com/protocol-buffers/docs/overview https://developers.google.com/protocol-buffers/docs/javatutorial

JSON, where alibaba's fastJson is used

1. Introducing dependencies

<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>fastjson</artifactId>
      <version>1.2.62</version>
    </dependency>

1. Writing test classes

public class Student {

    private String name;

    private int age;

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

public class FastJsonTest {
    public static void main(String[] args) {
        Student student = new Student();
        student.setAge(11);
        student.setName("Number of sheets");

        String result = JSON.toJSONString(student);

        System.out.println(result);

        Student student1 = JSON.parseObject(result, Student.class);

        System.out.println(student1);
    }
}

Related links: https://github.com/alibaba/fastjson

MsgPack

1. Introducing dependencies

 <!-- https://mvnrepository.com/artifact/org.msgpack/msgpack -->
    <dependency>
      <groupId>org.msgpack</groupId>
      <artifactId>msgpack</artifactId>
      <version>0.6.12</version>
    </dependency>

1. Write related tests

public class MsgPackTest {

    public static void main(String[] args) throws IOException {
        MessagePack messagePack = new MessagePack();
        Student student = new Student();
        student.setName("zhangsan");
        student.setAge(11);
        
        byte[] result = messagePack.write(student);

        System.out.println(result);
        
        Student student1 = messagePack.read(result, Student.class);

        System.out.println(student1);
		
		// Create serialize objects.
List<String> src = new ArrayList<String>();
src.add("msgpack");
src.add("kumofs");
src.add("viver");
		
		
		// Serialize
byte[] raw = msgpack.write(src);

// Deserialize directly using a template
List<String> dst1 = msgpack.read(raw, Templates.tList(Templates.TString));
System.out.println(dst1.get(0));
System.out.println(dst1.get(1));
System.out.println(dst1.get(2));

// Or, Deserialze to Value then convert type.
Value dynamic = msgpack.read(raw);
List<String> dst2 = new Converter(dynamic)
    .read(Templates.tList(Templates.TString));
System.out.println(dst2.get(0));
System.out.println(dst2.get(1));
System.out.println(dst2.get(2));
    }
}

Related links: https://msgpack.org/

hessian

1. Introducing dependencies

  <!-- https://mvnrepository.com/artifact/com.caucho/hessian -->
    <dependency>
      <groupId>com.caucho</groupId>
      <artifactId>hessian</artifactId>
      <version>4.0.63</version>
    </dependency>

1. Writing test classes

public class HessianTest {

    public static void main(String[] args) throws IOException {

        ByteArrayOutputStream os = new ByteArrayOutputStream();
        Hessian2Output output = new Hessian2Output(os);
        output.writeObject("23456789");
        output.close();

        ByteArrayInputStream in = new ByteArrayInputStream(os.toByteArray());
        Hessian2Input input = new Hessian2Input(in);
        System.out.println(input.readObject());
    }
}

Related links: http://hessian.caucho.com/doc/hessian-serialization.html

summary

When choosing a serialization framework, consider performance, supported scopes (such as pan-hua, parent-child classes), whether collection types will be lost, and so on.

Welcome to my public number: Zhang Hengqiang's study notes