Netty学习9-序列化框架protocbuf

1 概述

protocbuf是一个谷歌开发的非常流行的序列化框架，它支持数据结构化一次可以到处使用，甚至可以跨语言使用，通过代码生成工具生成不同语言的源代码， 得到技术界的广泛认同。

2 开发步骤

步骤1  准备工作
protoc.exe下载。windows版本的生成工具：protoc-2.5.0-win32.zip文件解压。
protocbuf-java-2.5.0.jar下载。

步骤2  编写proto文件

包名：java_package
模块：java_outer_classname。最终体现是StudentModule.java文件
类名：Student和Grade。StudentModule.java文件中有Student和Grade两个类

required：必填
repeated：列表

Int型：int32
long型：int64
String型：string

option java_package = "com.proto.xy";option java_outer_classname = "StudentModule";message Student{required int64 stuId = 1;required int32 age = 2;required string name = 3;repeated int32 hobbies = 4;}message Grade{required int32 id = 1;required string name = 2;}

步骤3  生成Java文件

编写批处理xy.bat文件，与protoc.exe文件同级

protoc ./proto/*.proto --java_out=./srcpause

步骤4  序列化代码

序列化和反序列化方法

import java.util.Arrays;import com.proto.xy.p.StudentModule.Student;import com.proto.xy.p.StudentModule.Student.Builder;public class Student2Bytes {public static void main(String[] args) throws Exception {byte[] bytes = toBytes();toPlayer(bytes);}/** * 序列化 */public static byte[] toBytes() {// 获取一个PBPlayer的构造器Builder builder = StudentModule.Student.newBuilder();// 设置数据builder.setStuId(1000).setAge(26).setName("xy").addHobbies(1).addHobbies(2);// 构造出对象Student student = builder.build();// 序列化成字节数组byte[] byteArray = student.toByteArray();System.out.println(Arrays.toString(byteArray));return byteArray;}/** * 反序列化 */public static void toPlayer(byte[] bs) throws Exception {Student student = StudentModule.Student.parseFrom(bs);System.out.println("studentId:" + student.getStuId());System.out.println("age:" + student.getAge());System.out.println("name:" + student.getName());System.out.println("hobbies:"+ (Arrays.toString(student.getHobbiesList().toArray())));}}

[8, -24, 7, 16, 26, 26, 2, 120, 121, 32, 1, 32, 2]
studentId:1000
age:26
name:xy
hobbies:[1, 2]

3 JDK原生序列化

通过输出结果对比，会发现probuf生成的字节数组小很多。

import java.io.Serializable;import java.util.ArrayList;import java.util.List;public class StudentJava implements Serializable {private static final long serialVersionUID = -5248069984631225347L;public StudentJava(long stuId, int age, String name) {this.stuId = stuId;this.age = age;this.name = name;}private long stuId;private int age;private String name;private List<Integer> hobbies = new ArrayList<>();public long getStuId() {return stuId;}public void setStuId(long stuId) {this.stuId = stuId;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getName() {return name;}public void setName(String name) {this.name = name;}public List<Integer> getHobbies() {return hobbies;}public void setHobbies(List<Integer> hobbies) {this.hobbies = hobbies;}}import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import java.util.ArrayList;import java.util.Arrays;import java.util.List;public class JAVA2Bytes {public static void main(String[] args) throws Exception {byte[] bytes = toBytes();toPlayer(bytes);}/** * 序列化 */public static byte[] toBytes() throws IOException {StudentJava student = new StudentJava(1000, 26, "xy");List<Integer> hobbies = new ArrayList<Integer>();hobbies.add(1);hobbies.add(2);student.setHobbies(hobbies);ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);// 写入对象objectOutputStream.writeObject(student);// 获取字节数组byte[] byteArray = byteArrayOutputStream.toByteArray();System.out.println(Arrays.toString(byteArray));return byteArray;}/** * 反序列化 */public static void toPlayer(byte[] bs) throws Exception {ObjectInputStream inputStream = new ObjectInputStream(new ByteArrayInputStream(bs));StudentJava student = (StudentJava) inputStream.readObject();System.out.println("studentId:" + student.getStuId());System.out.println("age:" + student.getAge());System.out.println("name:" + student.getName());System.out.println("hobbies:"+ (Arrays.toString(student.getHobbies().toArray())));}}

[-84, -19, 0, 5, 115, 114, 0, 26, 99, 111, 109, 46, 112, 114, 111, 116, 111, 46, 120, 121, 46, 106, 46, 83, 116, 117, 100, 101, 110, 116, 74, 97, 118, 97, -73, 43, 28, 39, -119, -86, -125, -3, 2, 0, 4, 73, 0, 3, 97, 103, 101, 74, 0, 5, 115, 116, 117, 73, 100, 76, 0, 7, 104, 111, 98, 98, 105, 101, 115, 116, 0, 16, 76, 106, 97, 118, 97, 47, 117, 116, 105, 108, 47, 76, 105, 115, 116, 59, 76, 0, 4, 110, 97, 109, 101, 116, 0, 18, 76, 106, 97, 118, 97, 47, 108, 97, 110, 103, 47, 83, 116, 114, 105, 110, 103, 59, 120, 112, 0, 0, 0, 26, 0, 0, 0, 0, 0, 0, 3, -24, 115, 114, 0, 19, 106, 97, 118, 97, 46, 117, 116, 105, 108, 46, 65, 114, 114, 97, 121, 76, 105, 115, 116, 120, -127, -46, 29, -103, -57, 97, -99, 3, 0, 1, 73, 0, 4, 115, 105, 122, 101, 120, 112, 0, 0, 0, 2, 119, 4, 0, 0, 0, 2, 115, 114, 0, 17, 106, 97, 118, 97, 46, 108, 97, 110, 103, 46, 73, 110, 116, 101, 103, 101, 114, 18, -30, -96, -92, -9, -127, -121, 56, 2, 0, 1, 73, 0, 5, 118, 97, 108, 117, 101, 120, 114, 0, 16, 106, 97, 118, 97, 46, 108, 97, 110, 103, 46, 78, 117, 109, 98, 101, 114, -122, -84, -107, 29, 11, -108, -32, -117, 2, 0, 0, 120, 112, 0, 0, 0, 1, 115, 113, 0, 126, 0, 6, 0, 0, 0, 2, 120, 116, 0, 2, 120, 121]
studentId:1000
age:26
name:xy
hobbies:[1, 2]