[Netty学习笔记]九、ProtoBuf的入门使用
概述
通过前面的学习，我们了解到数据在网络中传输的都是二进制字节码数据，因而在发送数据时就需要编码，接收数据时就需要解码。
codec(编解码器)的组成部分有两个：decoder(解码器)和encoder(编码器)。encoder负责把业务数据转换成字节码数据，decoder负责把字节码数据转换成业务数据
Netty中本身也提供了一些编解码器,如：
- StringEncoder/StringDecoder 对字符串进行编解码
- ObjectEncoder/ObjectDecoder 对Java对象进行编解码
- …
通过了解可以发现，Netty编解码器底层使用Java序列化技术来实现的。 但是Java序列化技术本身效率不高，而且无法跨语言，序列化后的体积太大(是二进制编码的5倍多)，序列化性能太低。因此转而选择使用ProtoBuf来实现序列化。
ProtoBuf的优点/特性：
- ProtiBuf以message的方式来管理数据
- 支持跨平台、跨语言
- 高性能、高可靠性
- 适合做数据存储或RPC
ProtoBuf的使用
使用步骤：
1、引入ProtoBuf依赖
2、编写.proto文件
3、使用protoc编译器将.proto文件自动生成为对应语言的文件(也可使用grpc来自动生成)
下面创建一个简单的proto文件并自动生成为Java文件：
1、引入3.6.1版本的依赖
<dependency>
<groupId>com.google.protobufgroupId>
<artifactId>protobuf-javaartifactId>
<version>3.6.1version>
dependency>
2、编写Student.proto文件(IDEA的话 可以装Proto插件)
syntax = "proto3"; //版本
option java_outer_classname = "StudentPOJO"; //生成的外部类名 同时也是文件名
//protobuf使用message管理数据
message Student { //会在StudentPOJO外部类生成一个内部类Student，真正用到的对象
int32 id=1;//student类中有一个属性 名字为id 类型为int32(protibuf类型) 1表示属性序号
string name=2;
}
如上创建一个proto文件，Student类是真正用到的对象，将是以一个内部类的方式展现在Java文件中，其中定义了两个成员变量：int id;String name。
3、使用编译器编译proto文件
注意：这里依赖的protobuf是3.6.1版本，因此编译器也要是3.6.1版本的,我这里下载的是osx-3.6.1版本的
protoc编译器下载
由于这里使用的是Java语言，因此执行命令如下：
将Student.proto文件拷贝到protoc编译器同级目录
protoc --java_out=. Student.proto
生成的StudengPOJO.Java文件如下:
// Generated by the protocol buffer compiler. DO NOT EDIT!
// source: Student.proto
public final class StudentPOJO {
private StudentPOJO() {}
public static void registerAllExtensions(
com.google.protobuf.ExtensionRegistryLite registry) {
}
public static void registerAllExtensions(
com.google.protobuf.ExtensionRegistry registry) {
registerAllExtensions(
(com.google.protobuf.ExtensionRegistryLite) registry);
}
public interface StudentOrBuilder extends
// @@protoc_insertion_point(interface_extends:Student)
com.google.protobuf.MessageOrBuilder {
/**
*
*student类中有一个属性 名字为id 类型为int32(protibuf类型) 1表示属性序号
*
*
* int32 id = 1;
*/
int getId();
/**
* string name = 2;
*/
String getName();
/**
* string name = 2;
*/
com.google.protobuf.ByteString
getNameBytes();
}
/**
*
*protobuf使用message管理数据
*
*
* Protobuf type {@code Student}
*/
public static final class Student extends
com.google.protobuf.GeneratedMessageV3 implements
// @@protoc_insertion_point(message_implements:Student)
StudentOrBuilder {
private static final long serialVersionUID = 0L;
// Use Student.newBuilder() to construct.
private Student(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
super(builder);
}
private Student() {
id_ = 0;
name_ = "";
}
@Override
public final com.google.protobuf.UnknownFieldSet
getUnknownFields() {
return this.unknownFields;
}
private Student(
com.google.protobuf.CodedInputStream input,
com.google.protobuf.ExtensionRegistryLite extensionRegistry)
throws com.google.protobuf.InvalidProtocolBufferException {
this();
if (extensionRegistry == null) {
throw new NullPointerException();
}
int mutable_bitField0_ = 0;
com.google.protobuf.UnknownFieldSet.Builder unknownFields =
com.google.protobuf.UnknownFieldSet.newBuilder();
try {
boolean done = false;
while (!done) {
int tag = input.readTag();
switch (tag) {
case 0:
done = true;
break;
case 8: {
id_ = input.readInt32();
break;
}
case 18: {
String s = input.readStringRequireUtf8();
name_ = s;
break;
}
default: {
if (!parseUnknownFieldProto3(
input, unknownFields, extensionRegistry, tag)) {
done = true;
}
break;
}
}
}
} catch (com.google.protobuf.InvalidProtocolBufferException e) {
throw e.setUnfinishedMessage(this);
} catch (java.io.IOException e) {
throw new com.google.protobuf.InvalidProtocolBufferException(
e).setUnfinishedMessage(this);
} finally {
this.unknownFields = unknownFields.build();
makeExtensionsImmutable();
}
}
public static final com.google.protobuf.Descriptors.Descriptor
getDescriptor() {
return StudentPOJO.internal_static_Student_descriptor;
}
@Override
protected FieldAccessorTable
internalGetFieldAccessorTable() {
return StudentPOJO.internal_static_Student_fieldAccessorTable
.ensureFieldAccessorsInitialized(
Student.class, Builder.class);
}
public static final int ID_FIELD_NUMBER = 1;
private int id_;
/**
*
*student类中有一个属性 名字为id 类型为int32(protibuf类型) 1表示属性序号
*
*
* int32 id = 1;
*/
public int getId() {
return id_;
}
public static final int NAME_FIELD_NUMBER = 2;
private volatile Object name_;
/**
* string name = 2;
*/
public String getName() {
Object ref = name_;
if (ref instanceof String) {
return (String) ref;
} else {
com.google.protobuf.ByteString bs =
(com.google.protobuf.ByteString) ref;
String s = bs.toStringUtf8();
name_ = s;
return s;
}
}
/**
* string name = 2;
*/
public com.google.protobuf.ByteString
getNameBytes() {
Object ref = name_;
if (ref instanceof String) {
com.google.protobuf.ByteString b =
com.google.protobuf.ByteString.copyFromUtf8(
(String) ref);
name_ = b;
return b;
} else {
return (com.google.protobuf.ByteString) ref;
}
}
private byte memoizedIsInitialized = -1;
@Override
public final boolean isInitialized() {
byte isInitialized = memoizedIsInitialized;
if (isInitialized == 1) return true;
if (isInitialized == 0) return false;
memoizedIsInitialized = 1;
return true;
}
@Override
public void writeTo(com.google.protobuf.CodedOutputStream output)
throws java.io.IOException {
if (id_ != 0) {
output.writeInt32(1, id_);
}
if (!getNameBytes().isEmpty()) {
com.google.protobuf.GeneratedMessageV3.writeString(output, 2, name_);
}
unknownFields.writeTo(output);
}
@Override
public int getSerializedSize() {
int size = memoizedSize;
if (size != -1) return size;
size = 0;
if (id_ != 0) {
size += com.google.protobuf.CodedOutputStream
.computeInt32Size(1, id_);
}
if (!getNameBytes().isEmpty()) {
size += com.google.protobuf.GeneratedMessageV3.computeStringSize(2, name_);
}
size += unknownFields.getSerializedSize();
memoizedSize = size;
return size;
}
@Override
public boolean equals(final Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof Student)) {
return super.equals(obj);
}
Student other = (Student) obj;
boolean result = true;
result = result && (getId()
== other.getId());
result = result && getName()
.equals(other.getName());
result = result && unknownFields.equals(other.unknownFields);
return result;
}
@Override
public int hashCode() {
if (memoizedHashCode != 0) {
return memoizedHashCode;
}
int hash = 41;
hash = (19 * hash) + getDescriptor().hashCode();
hash = (37 * hash) + ID_FIELD_NUMBER;
hash = (53 * hash) + getId();
hash = (37 * hash) + NAME_FIELD_NUMBER;
hash = (53 * hash) + getName().hashCode();
hash = (29 * hash) + unknownFields.hashCode();
memoizedHashCode = hash;
return hash;
}
public static Student parseFrom(
java.nio.ByteBuffer data)
throws com.google.protobuf.InvalidProtocolBufferException {
return PARSER.parseFrom(data);
}
public static Student parseFrom(
java.nio.ByteBuffer data,
com.google.protobuf.ExtensionRegistryLite extensionRegistry)
throws com.google.protobuf.InvalidProtocolBufferException {
return PARSER.parseFrom(data, extensionRegistry);
}
public static Student parseFrom(
com.google.protobuf.ByteString data)
throws com.google.protobuf.InvalidProtocolBufferException {
return PARSER.parseFrom(data);
}
public static Student parseFrom(
com.google.protobuf.ByteString data,
com.google.protobuf.ExtensionRegistryLite extensionRegistry)
throws com.google.protobuf.InvalidProtocolBufferException {
return PARSER.parseFrom(data, extensionRegistry);
}
public static Student parseFrom(byte[] data)
throws com.google.protobuf.InvalidProtocolBufferException {
return PARSER.parseFrom(data);
}
public static Student parseFrom(
byte[] data,
com.google.protobuf.ExtensionRegistryLite extensionRegistry)
throws com.google.protobuf.InvalidProtocolBufferException {
return PARSER.parseFrom(data, extensionRegistry);
}
public static Student parseFrom(java.io.InputStream input)
throws java.io.IOException {
return com.google.protobuf.GeneratedMessageV3
.parseWithIOException(PARSER, input);
}
public static Student parseFrom(
java.io.InputStream input,
com.google.protobuf.ExtensionRegistryLite extensionRegistry)
throws java.io.IOException {
return com.google.protobuf.GeneratedMessageV3
.parseWithIOException(PARSER, input, extensionRegistry);
}
public static Student parseDelimitedFrom(java.io.InputStream input)
throws java.io.IOException {
return com.google.protobuf.GeneratedMessageV3
.parseDelimitedWithIOException(PARSER, input);
}
public static Student parseDelimitedFrom(
java.io.InputStream input,
com.google.protobuf.ExtensionRegistryLite extensionRegistry)
throws java.io.IOException {
return com.google.protobuf.GeneratedMessageV3
.parseDelimitedWithIOException(PARSER, input, extensionRegistry);
}
public static Student parseFrom(
com.google.protobuf.CodedInputStream input)
throws java.io.IOException {
return com.google.protobuf.GeneratedMessageV3
.parseWithIOException(PARSER, input);
}
public static Student parseFrom(
com.google.protobuf.CodedInputStream input,
com.google.protobuf.ExtensionRegistryLite extensionRegistry)
throws java.io.IOException {
return com.google.protobuf.GeneratedMessageV3
.parseWithIOException(PARSER, input, extensionRegistry);
}
@Override
public Builder newBuilderForType() { return newBuilder(); }
public static Builder newBuilder() {
return DEFAULT_INSTANCE.toBuilder();
}
public static Builder newBuilder(Student prototype) {
return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
}
@Override
public Builder toBuilder() {
return this == DEFAULT_INSTANCE
? new Builder() : new Builder().mergeFrom(this);
}
@Override
protected Builder newBuilderForType(
BuilderParent parent) {
Builder builder = new Builder(parent);
return builder;
}
/**
*
*protobuf使用message管理数据
*
*
* Protobuf type {@code Student}
*/
public static final class Builder extends
com.google.protobuf.GeneratedMessageV3.Builder<Builder> implements
// @@protoc_insertion_point(builder_implements:Student)
StudentOrBuilder {
public static final com.google.protobuf.Descriptors.Descriptor
getDescriptor() {
return StudentPOJO.internal_static_Student_descriptor;
}
@Override
protected FieldAccessorTable
internalGetFieldAccessorTable() {
return StudentPOJO.internal_static_Student_fieldAccessorTable
.ensureFieldAccessorsInitialized(
Student.class, Builder.class);
}
// Construct using StudentPOJO.Student.newBuilder()
private Builder() {
maybeForceBuilderInitialization();
}
private Builder(
BuilderParent parent) {
super(parent);
maybeForceBuilderInitialization();
}
private void maybeForceBuilderInitialization() {
if (com.google.protobuf.GeneratedMessageV3
.alwaysUseFieldBuilders) {
}
}
@Override
public Builder clear() {
super.clear();
id_ = 0;
name_ = "";
return this;
}
@Override
public com.google.protobuf.Descriptors.Descriptor
getDescriptorForType() {
return StudentPOJO.internal_static_Student_descriptor;
}
@Override
public Student getDefaultInstanceForType() {
return Student.getDefaultInstance();
}
@Override
public Student build() {
Student result = buildPartial();
if (!result.isInitialized()) {
throw newUninitializedMessageException(result);
}
return result;
}
@Override
public Student buildPartial() {
Student result = new Student(this);
result.id_ = id_;
result.name_ = name_;
onBuilt();
return result;
}
@Override
public Builder clone() {
return (Builder) super.clone();
}
@Override
public Builder setField(
com.google.protobuf.Descriptors.FieldDescriptor field,
Object value) {
return (Builder) super.setField(field, value);
}
@Override
public Builder clearField(
com.google.protobuf.Descriptors.FieldDescriptor field) {
return (Builder) super.clearField(field);
}
@Override
public Builder clearOneof(
com.google.protobuf.Descriptors.OneofDescriptor oneof) {
return (Builder) super.clearOneof(oneof);
}
@Override
public Builder setRepeatedField(
com.google.protobuf.Descriptors.FieldDescriptor field,
int index, Object value) {
return (Builder) super.setRepeatedField(field, index, value);
}
@Override
public Builder addRepeatedField(
com.google.protobuf.Descriptors.FieldDescriptor field,
Object value) {
return (Builder) super.addRepeatedField(field, value);
}
@Override
public Builder mergeFrom(com.google.protobuf.Message other) {
if (other instanceof Student) {
return mergeFrom((Student)other);
} else {
super.mergeFrom(other);
return this;
}
}
public Builder mergeFrom(Student other) {
if (other == Student.getDefaultInstance()) return this;
if (other.getId() != 0) {
setId(other.getId());
}
if (!other.getName().isEmpty()) {
name_ = other.name_;
onChanged();
}
this.mergeUnknownFields(other.unknownFields);
onChanged();
return this;
}
@Override
public final boolean isInitialized() {
return true;
}
@Override
public Builder mergeFrom(
com.google.protobuf.CodedInputStream input,
com.google.protobuf.ExtensionRegistryLite extensionRegistry)
throws java.io.IOException {
Student parsedMessage = null;
try {
parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
} catch (com.google.protobuf.InvalidProtocolBufferException e) {
parsedMessage = (Student) e.getUnfinishedMessage();
throw e.unwrapIOException();
} finally {
if (parsedMessage != null) {
mergeFrom(parsedMessage);
}
}
return this;
}
private int id_ ;
/**
*
*student类中有一个属性 名字为id 类型为int32(protibuf类型) 1表示属性序号
*
*
* int32 id = 1;
*/
public int getId() {
return id_;
}
/**
*
*student类中有一个属性 名字为id 类型为int32(protibuf类型) 1表示属性序号
*
*
* int32 id = 1;
*/
public Builder setId(int value) {
id_ = value;
onChanged();
return this;
}
/**
*
*student类中有一个属性 名字为id 类型为int32(protibuf类型) 1表示属性序号
*
*
* int32 id = 1;
*/
public Builder clearId() {
id_ = 0;
onChanged();
return this;
}
private Object name_ = "";
/**
* string name = 2;
*/
public String getName() {
Object ref = name_;
if (!(ref instanceof String)) {
com.google.protobuf.ByteString bs =
(com.google.protobuf.ByteString) ref;
String s = bs.toStringUtf8();
name_ = s;
return s;
} else {
return (String) ref;
}
}
/**
* string name = 2;
*/
public com.google.protobuf.ByteString
getNameBytes() {
Object ref = name_;
if (ref instanceof String) {
com.google.protobuf.ByteString b =
com.google.protobuf.ByteString.copyFromUtf8(
(String) ref);
name_ = b;
return b;
} else {
return (com.google.protobuf.ByteString) ref;
}
}
/**
* string name = 2;
*/
public Builder setName(
String value) {
if (value == null) {
throw new NullPointerException();
}
name_ = value;
onChanged();
return this;
}
/**
* string name = 2;
*/
public Builder clearName() {
name_ = getDefaultInstance().getName();
onChanged();
return this;
}
/**
* string name = 2;
*/
public Builder setNameBytes(
com.google.protobuf.ByteString value) {
if (value == null) {
throw new NullPointerException();
}
checkByteStringIsUtf8(value);
name_ = value;
onChanged();
return this;
}
@Override
public final Builder setUnknownFields(
final com.google.protobuf.UnknownFieldSet unknownFields) {
return super.setUnknownFieldsProto3(unknownFields);
}
@Override
public final Builder mergeUnknownFields(
final com.google.protobuf.UnknownFieldSet unknownFields) {
return super.mergeUnknownFields(unknownFields);
}
// @@protoc_insertion_point(builder_scope:Student)
}
// @@protoc_insertion_point(class_scope:Student)
private static final Student DEFAULT_INSTANCE;
static {
DEFAULT_INSTANCE = new Student();
}
public static Student getDefaultInstance() {
return DEFAULT_INSTANCE;
}
private static final com.google.protobuf.Parser<Student>
PARSER = new com.google.protobuf.AbstractParser<Student>() {
@Override
public Student parsePartialFrom(
com.google.protobuf.CodedInputStream input,
com.google.protobuf.ExtensionRegistryLite extensionRegistry)
throws com.google.protobuf.InvalidProtocolBufferException {
return new Student(input, extensionRegistry);
}
};
public static com.google.protobuf.Parser<Student> parser() {
return PARSER;
}
@Override
public com.google.protobuf.Parser<Student> getParserForType() {
return PARSER;
}
@Override
public Student getDefaultInstanceForType() {
return DEFAULT_INSTANCE;
}
}
private static final com.google.protobuf.Descriptors.Descriptor
internal_static_Student_descriptor;
private static final
com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
internal_static_Student_fieldAccessorTable;
public static com.google.protobuf.Descriptors.FileDescriptor
getDescriptor() {
return descriptor;
}
private static com.google.protobuf.Descriptors.FileDescriptor
descriptor;
static {
String[] descriptorData = {
"\n\rStudent.proto\"#\n\007Student\022\n\n\002id\030\001 \001(\005\022\014" +
"\n\004name\030\002 \001(\tB\rB\013StudentPOJOb\006proto3"
};
com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner assigner =
new com.google.protobuf.Descriptors.FileDescriptor. InternalDescriptorAssigner() {
public com.google.protobuf.ExtensionRegistry assignDescriptors(
com.google.protobuf.Descriptors.FileDescriptor root) {
descriptor = root;
return null;
}
};
com.google.protobuf.Descriptors.FileDescriptor
.internalBuildGeneratedFileFrom(descriptorData,
new com.google.protobuf.Descriptors.FileDescriptor[] {
}, assigner);
internal_static_Student_descriptor =
getDescriptor().getMessageTypes().get(0);
internal_static_Student_fieldAccessorTable = new
com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
internal_static_Student_descriptor,
new String[] { "Id", "Name", });
}
// @@protoc_insertion_point(outer_class_scope)
}
将序列化后的Java类放到项目中即可使用
示例：基于ProtoBuf实现简单的通讯
- 客户端发送一个Student对象到服务器
- 服务器端接收到Student对象 并显示信息
- 使用ProtoBuf编解码
服务器端
public class NettyProtoBufServer {
public static void main(String[] args) {
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.option(ChannelOption.SO_BACKLOG, 128)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
//对哪种类型进行解码
pipeline.addLast("decoder", new ProtobufDecoder(StudentPOJO.Student.getDefaultInstance()));
pipeline.addLast(new NettyProtoBufHandler());
}
});
ChannelFuture channelFuture = serverBootstrap.bind(8899).sync();
channelFuture.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
} finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
//handler
public class NettyProtoBufHandler extends ChannelInboundHandlerAdapter {
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
StudentPOJO.Student student = (StudentPOJO.Student) msg;
System.out.println("from client:" + student.getId() + "====>" + student.getName());
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.writeAndFlush(Unpooled.copiedBuffer("msg from server", CharsetUtil.UTF_8));
}
}
客户端代码
public class NettyProtoBufClient {
public static void main(String[] args) {
EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(eventLoopGroup)
.channel(NioSocketChannel.class)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
//编码器
pipeline.addLast("encoder", new ProtobufEncoder());
pipeline.addLast(new NettyProtoBufClientHandler());
}
});
ChannelFuture channelFuture = bootstrap.connect("127.0.0.1", 8899).sync();
channelFuture.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
} finally {
eventLoopGroup.shutdownGracefully();
}
}
}
//handler
public class NettyProtoBufClientHandler extends ChannelInboundHandlerAdapter {
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
StudentPOJO.Student student = StudentPOJO.Student.newBuilder().setId(1).setName("abc").build();
ctx.writeAndFlush(student);
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
ByteBuf buf= (ByteBuf) msg;
System.out.println(buf.toString(CharsetUtil.UTF_8));
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
super.exceptionCaught(ctx, cause);
}
}
注意：这里在客户端和服务器端加上了与ProtoBuf有关的编解码器
上面的例子服务器端只会生成一种特定类型的对象，如果服务器端想要根据业务获取不同类型的对象可参见下面的例子
syntax = "proto3";
option java_outer_classname = "RolePOJO";
option java_package = "com.wojiushiwo.protobuf.multi";
message Role {
//declare enum
enum DataType {
Student = 0;
Worker = 1;
}
//first field
DataType dataType = 1;
//can select one of declared field
oneof dataBody {
Student student = 2;
Worker worker = 3;
}
}
message Student {
int32 id = 1;
string name = 2;
}
message Worker {
string name = 1;
int32 age = 2;
}
服务端代码
public class NettyMultiProtoBufTypeServer {
public static void main(String[] args) {
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.option(ChannelOption.SO_BACKLOG, 128)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
// 这里服务器端添加的是针对protoBuf的解码器
pipeline.addLast("decoder", new ProtobufDecoder(RolePOJO.Role.getDefaultInstance()));
pipeline.addLast(new MultiProtoBufServerHandler());
}
});
ChannelFuture channelFuture = serverBootstrap.bind(8900).sync();
channelFuture.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
} finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
//handler
public class MultiProtoBufServerHandler extends SimpleChannelInboundHandler<RolePOJO.Role> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, RolePOJO.Role msg) throws Exception {
RolePOJO.Role.DataType dataType = msg.getDataType();
if (Objects.equals(dataType, RolePOJO.Role.DataType.Student)) {
RolePOJO.Student student = msg.getStudent();
System.out.println("获取到客户端发送的信息：" + student.getId() + "," + student.getName());
} else if (Objects.equals(dataType, RolePOJO.Role.DataType.Worker)) {
RolePOJO.Worker worker = msg.getWorker();
System.out.println("获取到客户端发送的信息：" + worker.getAge() + "," + worker.getName());
} else {
System.out.println("获取到客户端发送的信息");
}
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
客户端代码
package com.wojiushiwo.protobuf.multi;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.protobuf.ProtobufEncoder;
/**
* Created by myk
* 2020/1/29 下午5:40
*/
public class NettyMultiProtoBufTypeClient {
public static void main(String[] args) {
EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(eventLoopGroup)
.channel(NioSocketChannel.class)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(new ProtobufEncoder());
pipeline.addLast(new MultiProtoBufClientHandler());
}
});
ChannelFuture channelFuture = bootstrap.connect("127.0.0.1", 8900).sync();
channelFuture.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
} finally {
eventLoopGroup.shutdownGracefully();
}
}
}
//handler
package com.wojiushiwo.protobuf.multi;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
/**
* Created by myk
* 2020/1/29 下午5:41
*/
public class MultiProtoBufClientHandler extends ChannelInboundHandlerAdapter {
public static void main(String[] args) {
System.out.println((int) (Math.random() * 10));
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
int randomNum = (int) (Math.random() * 10);
RolePOJO.Role role;
if (randomNum % 2 == 0) {
RolePOJO.Student student = RolePOJO.Student.newBuilder().setId(1).setName("student").build();
role = RolePOJO.Role.newBuilder().setDataType(RolePOJO.Role.DataType.Student)
.setStudent(student).build();
} else {
RolePOJO.Worker worker = RolePOJO.Worker.newBuilder().setAge(20).setName("worker").build();
role = RolePOJO.Role.newBuilder().setDataType(RolePOJO.Role.DataType.Worker)
.setWorker(worker).build();
}
ctx.writeAndFlush(role);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
上面使用到了ProtoBuf中的语法enum,如果想查看ProtoBuf语法的其他用法可参见ProtoBuf语法