java 序列化 protobuf_Java序列化和Protobuf

序列化

原理无非将对象压缩成字符流，需要的时候再取出来；

这种情况在分布式用的比较多，类似的Xml和Json也可以实现这种效果；

下面放一个Java序列化的例子

1.创建实例化对象

package com.bean;

import java.io.Serializable;

import java.util.List;

/**

* @author: jane

* @CreateTime: 2020/5/11

* @Description:

*/

public class MyProto implements Serializable {

int userID;

String userName;

List hobby;

public MyProto(int userID, String userName, List hobby){

this.userID = userID;

this.userName = userName;

this.hobby = hobby;

}

@Override

public String toString() {

return "MyProto{" +

"userID=" + userID +

", userName='" + userName + '\'' +

", hobby=" + hobby +

'}';

}

}

如果有不希望被序列化的属性，可以加上transient；

2.编写测试

package com.serializable;

import com.bean.MyProto;

import java.io.*;

import java.util.ArrayList;

import java.util.List;

/**

* @author: jane

* @CreateTime: 2020/5/11

* @Description:

*/

public class SerializableTest {

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

List hobby = new ArrayList<>();

hobby.add("Programming");

hobby.add("Reading");

hobby.add("Playing Games");

MyProto proto = new MyProto(666, "Jane", hobby);

System.out.println("Before encode:"+proto.toString());

FileOutputStream fos = new FileOutputStream(new File("src/main/resources/serial.out"));

ObjectOutputStream oos = new ObjectOutputStream(fos);

oos.writeObject(proto);

FileInputStream fis = new FileInputStream(new File("src/main/resources/serial.out"));

ObjectInputStream ois = new ObjectInputStream(fis);

MyProto proto2 = (MyProto)ois.readObject();

System.out.println("After decode:"+proto2.toString());

}

}

3.输出结果，符合预期

Before encode:MyProto{userID=666, userName='Jane', hobby=[Programming, Reading, Playing Games]}

After decode:MyProto{userID=666, userName='Jane', hobby=[Programming, Reading, Playing Games]}

Protobuf

Protobuf也是用于序列化的，而且Protobuf的效率比较高，适合常见语言；

Java自带的Serializable就比较专一了。。。

下面演示Windows版的例子

1.下载

里面的protoc.exe是关键

2.编写MyProto.proto

option java_package = "com.protobuf";

option java_outer_classname = "MyProtoName";

message MyProto{

required int32 userID = 1;

required string userName = 2;

repeated string hobby = 3;

}

3.Cmd下，通过Protobuf生成Java文件

protoc.exe --java_out=.\ .\MyProto.proto

4.把生成的Java文件放到项目对应位置，编写测试

package com.protobuf;

import com.google.protobuf.InvalidProtocolBufferException;

import java.io.Serializable;

import java.util.ArrayList;

import java.util.List;

/**

* @author: jane

* @CreateTime: 2020/5/11

* @Description:

*/

public class ProtoTest {

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

MyProtoName.MyProto proto = create();

System.out.println("Before encode:");

System.out.println(proto.toString());

MyProtoName.MyProto proto2 = decode(encode(proto));

System.out.println("After decode:");

System.out.println(proto2.toString());

System.out.println(proto.equals(proto2));

}

private static MyProtoName.MyProto create(){

MyProtoName.MyProto.Builder builder = MyProtoName.MyProto.newBuilder();

builder.setUserID(777);

builder.setUserName("Jayying");

List hobby = new ArrayList<>();

hobby.add("Programming");

hobby.add("Reading");

hobby.add("Playing Games");

builder.addAllHobby(hobby);

return builder.build();

}

private static byte[] encode(MyProtoName.MyProto proto){

return proto.toByteArray();

}

private static MyProtoName.MyProto decode(byte[] code) throws InvalidProtocolBufferException {

return MyProtoName.MyProto.parseFrom(code);

}

}

5.结果输出，符合预期

Before encode:

userID: 777

userName: "Jayying"

hobby: "Programming"

hobby: "Reading"

hobby: "Playing Games"

After decode:

userID: 777

userName: "Jayying"

hobby: "Programming"

hobby: "Reading"

hobby: "Playing Games"

true