google protobuf 对象转字节码 博客分类： Java

1、开源地址：

https://github.com/google/protobuf/

2、发布版本下载：

https://github.com/google/protobuf/releases

 

3、什么是Protobuf

官方文档给出的是：

 

a language-neutral, platform-neutral, extensible way of serializing structured data for use in communications protocols, data storage, and more.

 

3、数据类型

 

.proto       Type	Notes	C++ Type	Java Type
double		double	double
float		float	float
int32	Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint32 instead.	int32	int
int64	Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint64 instead.	int64	long
uint32	Uses variable-length encoding.	uint32	int
uint64	Uses variable-length encoding.	uint64	long
sint32	Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int32s.	int32	int
sint64	Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int64s.	int64	long
fixed32	Always four bytes. More efficient than uint32 if values are often greater than 228.	uint32	int
fixed64	Always eight bytes. More efficient than uint64 if values are often greater than 256.	uint64	long
sfixed32	Always four bytes.	int32	int
sfixed64	Always eight bytes.	int64	long
bool		bool	boolean
string	A string must always contain UTF-8 encoded or 7-bit ASCII text.	string	String
bytes	May contain any arbitrary sequence of bytes.	string	ByteString

  

 

 5、Protobuf的优点

1、性能好，效率高

2、代码生成机制，数据解析类自动生成

3、支持向后兼容和向前兼容

4、支持多种编程语言（java，c++，python）

 

6、Protobuf的缺点

1、应用不够广

2、二进制格式导致可读性差（二进制格式）

3、缺乏自描述

 

7、Protobuf环境的搭建

根据不同操作系统下载不同的发布版本

https://github.com/google/protobuf/releases，

 

8、新建第一个proto文件

文件名为：ResponseMsg.proto

option java_package = "io.hpgary.netty.pb"; //生成java的包名
option java_outer_classname = "ResponseMsgProbuf"; // 生成java的类名
  
message  ResponseMsg {
    required bytes response = 1;
}

9、转换成为java类：

使用命令：

# ../java 是源代码所在目录
protoc.exe --java_out ../java ResponseMsg.proto

 

10、使用：

ByteString byteString = ByteString.copyFrom("aaa".getBytes());
RequestMsg.Builder requstMsg = RequestMsg.newBuilder();
requstMsg.setCmd("hp_call");
requstMsg.setRequestParam( byteString );