Protocol Buffer序列化对比Java序列化.

初识

Protocol Buff是谷歌推出的一种序列化协议. 而Java序列化协议也是一种协议.

两者的目的是, 将对象序列化成字节数组, 或者说是二进制数据, 那么他们之间有什么差异呢.

proto对象

要使用PB, 我们需要定义一个proto对象, 其支持的数据类型如下:

Protobuf定义了一套基本数据类型。几乎都可以映射到C++Java等语言的基础数据类型.

      

protobuf 数据类型	描述	打包	C++语言映射
bool	布尔类型	1字节	bool
double	64位浮点数	N	double
float	32为浮点数	N	float
int32	32位整数、	N	int
uin32	无符号32位整数	N	unsigned int
int64	64位整数	N	__int64
uint64	64为无符号整	N	unsigned __int64
sint32	32位整数，处理负数效率更高	N	int32
sing64	64位整数 处理负数效率更高	N	__int64
fixed32	32位无符号整数	4	unsigned int32
fixed64	64位无符号整数	8	unsigned __int64
sfixed32	32位整数、能以更高的效率处理负数	4	unsigned int32
sfixed64	64为整数	8	unsigned __int64
string	只能处理 ASCII字符	N	std::string
bytes	用于处理多字节的语言字符、如中文	N	std::string
enum	可以包含一个用户自定义的枚举类型uint32	N(uint32)	enum
message	可以包含一个用户自定义的消息类型	N	object of class

proto对象结构类似于java的class, 在同一个module里, 定义了两个类, PBPlayer 和 PBResource, 各自拥有一些成员变量.

option java_package = "com.proto";
option java_outer_classname = "PlayerModule";

message PBPlayer{
    required int64 playerId = 1;
    
    required int32 age = 2;
    
    required string name = 3;
    
    repeated int32 skills = 4;
}

message PBResource{
    required int64 gold = 1;
    
    required int32 energy = 2;
}

然后用protoc.exe将proto对象转为java对象, 打开cmd, 运行如下命令:

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

生成的java对象比较庞大, 我们不需要细究里面代码, 直接调用即可.

// Generated by the protocol buffer compiler.  DO NOT EDIT!
// source: proto/player.proto

package com.proto;

public final class PlayerModule {
  private PlayerModule() {}
  public static void registerAllExtensions(
      com.google.protobuf.ExtensionRegistry registry) {
  }
  public interface PBPlayerOrBuilder
      extends com.google.protobuf.MessageOrBuilder {
    
    // required int64 playerId = 1;
    boolean hasPlayerId();
    long getPlayerId();
    
    // required int32 age = 2;
    boolean hasAge();
    int getAge();
    
    // required string name = 3;
    boolean hasName();
    String getName();
    
    // repeated int32 skills = 4;
    java.util.List<java.lang.Integer> getSkillsList();
    int getSkillsCount();
    int getSkills(int index);
  }
  public static final class PBPlayer extends
      com.google.protobuf.GeneratedMessage
      implements PBPlayerOrBuilder {
    // Use PBPlayer.newBuilder() to construct.
    private PBPlayer(Builder builder) {
      super(builder);
    }
    private PBPlayer(boolean noInit) {}
    
    private static final PBPlayer defaultInstance;
    public static PBPlayer getDefaultInstance() {
      return defaultInstance;
    }
    
    public PBPlayer getDefaultInstanceForType() {
      return defaultInstance;
    }
    
    public static final com.google.protobuf.Descriptors.Descriptor
        getDescriptor() {
      return com.proto.PlayerModule.internal_static_PBPlayer_descriptor;
    }
    
    protected com.google.protobuf.GeneratedMessage.FieldAccessorTable
        internalGetFieldAccessorTable() {
      return com.proto.PlayerModule.internal_static_PBPlayer_fieldAccessorTable;
    }
    
    private int bitField0_;
    // required int64 playerId = 1;
    public static final int PLAYERID_FIELD_NUMBER = 1;
    private long playerId_;
    public boolean hasPlayerId() {
      return ((bitField0_ & 0x00000001) == 0x00000001);
    }
    public long getPlayerId() {
      return playerId_;
    }
    
    // required int32 age = 2;
    public static final int AGE_FIELD_NUMBER = 2;
    private int age_;
    public boolean hasAge() {
      return ((bitField0_ & 0x00000002) == 0x00000002);
    }
    public int getAge() {
      return age_;
    }
    
    // required string name = 3;
    public static final int NAME_FIELD_NUMBER = 3;
    private java.lang.Object name_;
    public boolean hasName() {
      return ((bitField0_ & 0x00000004) == 0x00000004);
    }
    public String getName() {
      java.lang.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();
        if (com.google.protobuf.Internal.isValidUtf8(bs)) {
          name_ = s;
        }
        return s;
      }
    }
    private com.google.protobuf.ByteString getNameBytes() {
      java.lang.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;
      }
    }
    
    // repeated int32 skills = 4;
    public static final int SKILLS_FIELD_NUMBER = 4;
    private java.util.List<java.lang.Integer> skills_;
    public java.util.List<java.lang.Integer>
        getSkillsList() {
      return skills_;
    }
    public int getSkillsCount() {
      return skills_.size();
    }
    public int getSkills(int index) {
      return skills_.get(index);
    }
    
    private void initFields() {
      playerId_ = 0L;
      age_ = 0;
      name_ = "";
      skills_ = java.util.Collections.emptyList();;
    }
    private byte memoizedIsInitialized = -1;
    public final boolean isInitialized() {
      byte isInitialized = memoizedIsInitialized;
      if (isInitialized != -1) return isInitialized == 1;
      
      if (!hasPlayerId()) {
        memoizedIsInitialized = 0;
        return false;
      }
      if (!hasAge()) {
        memoizedIsInitialized = 0;
        return false;
      }
      if (!hasName()) {
        memoizedIsInitialized = 0;
        return false;
      }
      memoizedIsInitialized = 1;
      return true;
    }
    
    public void writeTo(com.google.protobuf.CodedOutputStream output)
                        throws java.io.IOException {
      getSerializedSize();
      if (((bitField0_ & 0x00000001) == 0x00000001)) {
        output.writeInt64(1, playerId_);
      }
      if (((bitField0_ & 0x00000002) == 0x00000002)) {
        output.writeInt32(2, age_);
      }
      if (((bitField0_ & 0x00000004) == 0x00000004)) {
        output.writeBytes(3, getNameBytes());
      }
      for (int i = 0; i < skills_.size(); i++) {
        output.writeInt32(4, skills_.get(i));
      }
      getUnknownFields().writeTo(output);
    }
    
    private int memoizedSerializedSize = -1;
    public int getSerializedSize() {
      int size = memoizedSerializedSize;
      if (size != -1) return size;
    
      size = 0;
      if (((bitField0_ & 0x00000001) == 0x00000001)) {
        size += com.google.protobuf.CodedOutputStream
          .computeInt64Size(1, playerId_);
      }
      if (((bitField0_ & 0x00000002) == 0x00000002)) {
        size += com.google.protobuf.CodedOutputStream
          .computeInt32Size(2, age_);
      }
      if (((bitField0_ & 0x00000004) == 0x00000004)) {
        size += com.google.protobuf.CodedOutputStream
          .computeBytesSize(3, getNameBytes());
      }
      {
        int dataSize = 0;
        for (int i = 0; i < skills_.size(); i++) {
          dataSize += com.google.protobuf.CodedOutputStream
            .computeInt32SizeNoTag(skills_.get(i));
        }
        size += dataSize;
        size += 1 * getSkillsList().size();
      }
      size += getUnknownFields().getSerializedSize();
      memoizedSerializedSize = size;
      return size;
    }
    
    private static final long serialVersionUID = 0L;
    @java.lang.Override
    protected java.lang.Object writeReplace()
        throws java.io.ObjectStreamException {
      return super.writeReplace();
    }
    
    public static com.proto.PlayerModule.PBPlayer parseFrom(
        com.google.protobuf.ByteString data)
        throws com.google.protobuf.InvalidProtocolBufferException {
      return newBuilder().mergeFrom(data).buildParsed();
    }
    public static com.proto.PlayerModule.PBPlayer parseFrom(
        com.google.protobuf.ByteString data,
        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
        throws com.google.protobuf.InvalidProtocolBufferException {
      return newBuilder().mergeFrom(data, extensionRegistry)
               .buildParsed();
    }
    public static com.proto.PlayerModule.PBPlayer parseFrom(byte[] data)
        throws com.google.protobuf.InvalidProtocolBufferException {
      return newBuilder().mergeFrom(data).buildParsed();
    }
    public static com.proto.PlayerModule.PBPlayer parseFrom(
        byte[] data,
        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
        throws com.google.protobuf.InvalidProtocolBufferException {
      return newBuilder().mergeFrom(data, extensionRegistry)
               .buildParsed();
    }
    public static com.proto.PlayerModule.PBPlayer parseFrom(java.io.InputStream input)
        throws java.io.IOException {
      return newBuilder().mergeFrom(input).buildParsed();
    }
    public static com.proto.PlayerModule.PBPlayer parseFrom(
        java.io.InputStream input,
        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
        throws java.io.IOException {
      return newBuilder().mergeFrom(input, extensionRegistry)
               .buildParsed();
    }
    public static com.proto.PlayerModule.PBPlayer parseDelimitedFrom(java.io.InputStream input)
        throws java.io.IOException {
      Builder builder = newBuilder();
      if (builder.mergeDelimitedFrom(input)) {
        return builder.buildParsed();
      } else {
        return null;
      }
    }
    public static com.proto.PlayerModule.PBPlayer parseDelimitedFrom(
        java.io.InputStream input,
        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
        throws java.io.IOException {
      Builder builder = newBuilder();
      if (builder.mergeDelimitedFrom(input, extensionRegistry)) {
        return builder.buildParsed();
      } else {
        return null;
      }
    }
    public static com.proto.PlayerModule.PBPlayer parseFrom(
        com.google.protobuf.CodedInputStream input)
        throws java.io.IOException {
      return newBuilder().mergeFrom(input).buildParsed();
    }
    public static com.proto.PlayerModule.PBPlayer parseFrom(
        com.google.protobuf.CodedInputStream input,
        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
        throws java.io.IOException {
      return newBuilder().mergeFrom(input, extensionRegistry)
               .buildParsed();
    }
    
    public static Builder newBuilder() { return Builder.create(); }
    public Builder newBuilderForType() { return newBuilder(); }
    public static Builder newBuilder(com.proto.PlayerModule.PBPlayer prototype) {
      return newBuilder().mergeFrom(prototype);
    }
    public Builder toBuilder() { return newBuilder(this); }
    
    @java.lang.Override
    protected Builder newBuilderForType(
        com.google.protobuf.GeneratedMessage.BuilderParent parent) {
      Builder builder = new Builder(parent);
      return builder;
    }
    public static final class Builder extends
        com.google.protobuf.GeneratedMessage.Builder<Builder>
       implements com.proto.PlayerModule.PBPlayerOrBuilder {
      public static final com.google.protobuf.Descriptors.Descriptor
          getDescriptor() {
        return com.proto.PlayerModule.internal_static_PBPlayer_descriptor;
      }
      
      protected com.google.protobuf.GeneratedMessage.FieldAccessorTable
          internalGetFieldAccessorTable() {
        return com.proto.PlayerModule.internal_static_PBPlayer_fieldAccessorTable;
      }
      
      // Construct using com.proto.PlayerModule.PBPlayer.newBuilder()
      private Builder() {
        maybeForceBuilderInitialization();
      }
      
      private Builder(BuilderParent parent) {
        super(parent);
        maybeForceBuilderInitialization();
      }
      private void maybeForceBuilderInitialization() {
        if (com.google.protobuf.GeneratedMessage.alwaysUseFieldBuilders) {
        }
      }
      private static Builder create() {
        return new Builder();
      }
      
      public Builder clear() {
        super.clear();
        playerId_ = 0L;
        bitField0_ = (bitField0_ & ~0x00000001);
        age_ = 0;
        bitField0_ = (bitField0_ & ~0x00000002);
        name_ = "";
        bitField0_ = (bitField0_ & ~0x00000004);
        skills_ = java.util.Collections.emptyList();;
        bitField0_ = (bitField0_ & ~0x00000008);
        return this;
      }
      
      public Builder clone() {
        return create().mergeFrom(buildPartial());
      }
      
      public com.google.protobuf.Descriptors.Descriptor
          getDescriptorForType() {
        return com.proto.PlayerModule.PBPlayer.getDescriptor();
      }
      
      public com.proto.PlayerModule.PBPlayer getDefaultInstanceForType() {
        return com.proto.PlayerModule.PBPlayer.getDefaultInstance();
      }
      
      public com.proto.PlayerModule.PBPlayer build() {
        com.proto.PlayerModule.PBPlayer result = buildPartial();
        if (!result.isInitialized()) {
          throw newUninitializedMessageException(result);
        }
        return result;
      }
      
      private com.proto.PlayerModule.PBPlayer buildParsed()
          throws com.google.protobuf.InvalidProtocolBufferException {
        com.proto.PlayerModule.PBPlayer result = buildPartial();
        if (!result.isInitialized()) {
          throw newUninitializedMessageException(
            result).asInvalidProtocolBufferException();
        }
        return result;
      }
      
      public com.proto.PlayerModule.PBPlayer buildPartial() {
        com.proto.PlayerModule.PBPlayer result = new com.proto.PlayerModule.PBPlayer(this);
        int from_bitField0_ = bitField0_;
        int to_bitField0_ = 0;
        if (((from_bitField0_ & 0x00000001) == 0x00000001)) {
          to_bitField0_ |= 0x00000001;
        }
        result.playerId_ = playerId_;
        if (((from_bitField0_ & 0x00000002) == 0x00000002)) {
          to_bitField0_ |= 0x00000002;
        }
        result.age_ = age_;
        if (((from_bitField0_ & 0x00000004) == 0x00000004)) {
          to_bitField0_ |= 0x00000004;
        }
        result.name_ = name_;
        if (((bitField0_ & 0x00000008) == 0x00000008)) {
          skills_ = java.util.Collections.unmodifiableList(skills_);
          bitField0_ = (bitField0_ & ~0x00000008);
        }
        result.skills_ = skills_;
        result.bitField0_ = to_bitField0_;
        onBuilt();
        return result;
      }
      
      public Builder mergeFrom(com.google.protobuf.Message other) {
        if (other instanceof com.proto.PlayerModule.PBPlayer) {
          return mergeFrom((com.proto.PlayerModule.PBPlayer)other);
        } else {
          super.mergeFrom(other);
          return this;
        }
      }
      
      public Builder mergeFrom(com.proto.PlayerModule.PBPlayer other) {
        if (other == com.proto.PlayerModule.PBPlayer.getDefaultInstance()) return this;
        if (other.hasPlayerId()) {
          setPlayerId(other.getPlayerId());
        }
        if (other.hasAge()) {
          setAge(other.getAge());
        }
        if (other.hasName()) {
          setName(other.getName());
        }
        if (!other.skills_.isEmpty()) {
          if (skills_.isEmpty()) {
            skills_ = other.skills_;
            bitField0_ = (bitField0_ & ~0x00000008);
          } else {
            ensureSkillsIsMutable();
            skills_.addAll(other.skills_);
          }
          onChanged();
        }
        this.mergeUnknownFields(other.getUnknownFields());
        return this;
      }
      
      public final boolean isInitialized() {
        if (!hasPlayerId()) {
          
          return false;
        }
        if (!hasAge()) {
          
          return false;
        }
        if (!hasName()) {
          
          return false;
        }
        return true;
      }
      
      public Builder mergeFrom(
          com.google.protobuf.CodedInputStream input,
          com.google.protobuf.ExtensionRegistryLite extensionRegistry)
          throws java.io.IOException {
        com.google.protobuf.UnknownFieldSet.Builder unknownFields =
          com.google.protobuf.UnknownFieldSet.newBuilder(
            this.getUnknownFields());
        while (true) {
          int tag = input.readTag();
          switch (tag) {
            case 0:
              this.setUnknownFields(unknownFields.build());
              onChanged();
              return this;
            default: {
              if (!parseUnknownField(input, unknownFields,
                                     extensionRegistry, tag)) {
                this.setUnknownFields(unknownFields.build());
                onChanged();
                return this;
              }
              break;
            }
            case 8: {
              bitField0_ |= 0x00000001;
              playerId_ = input.readInt64();
              break;
            }
            case 16: {
              bitField0_ |= 0x00000002;
              age_ = input.readInt32();
              break;
            }
            case 26: {
              bitField0_ |= 0x00000004;
              name_ = input.readBytes();
              break;
            }
            case 32: {
              ensureSkillsIsMutable();
              skills_.add(input.readInt32());
              break;
            }
            case 34: {
              int length = input.readRawVarint32();
              int limit = input.pushLimit(length);
              while (input.getBytesUntilLimit() > 0) {
                addSkills(input.readInt32());
              }
              input.popLimit(limit);
              break;
            }
          }
        }
      }
      
      private int bitField0_;
      
      // required int64 playerId = 1;
      private long playerId_ ;
      public boolean hasPlayerId() {
        return ((bitField0_ & 0x00000001) == 0x00000001);
      }
      public long getPlayerId() {
        return playerId_;
      }
      public Builder setPlayerId(long value) {
        bitField0_ |= 0x00000001;
        playerId_ = value;
        onChanged();
        return this;
      }
      public Builder clearPlayerId() {
        bitField0_ = (bitField0_ & ~0x00000001);
        playerId_ = 0L;
        onChanged();
        return this;
      }
      
      // required int32 age = 2;
      private int age_ ;
      public boolean hasAge() {
        return ((bitField0_ & 0x00000002) == 0x00000002);
      }
      public int getAge() {
        return age_;
      }
      public Builder setAge(int value) {
        bitField0_ |= 0x00000002;
        age_ = value;
        onChanged();
        return this;
      }
      public Builder clearAge() {
        bitField0_ = (bitField0_ & ~0x00000002);
        age_ = 0;
        onChanged();
        return this;
      }
      
      // required string name = 3;
      private java.lang.Object name_ = "";
      public boolean hasName() {
        return ((bitField0_ & 0x00000004) == 0x00000004);
      }
      public String getName() {
        java.lang.Object ref = name_;
        if (!(ref instanceof String)) {
          String s = ((com.google.protobuf.ByteString) ref).toStringUtf8();
          name_ = s;
          return s;
        } else {
          return (String) ref;
        }
      }
      public Builder setName(String value) {
        if (value == null) {
    throw new NullPointerException();
  }
  bitField0_ |= 0x00000004;
        name_ = value;
        onChanged();
        return this;
      }
      public Builder clearName() {
        bitField0_ = (bitField0_ & ~0x00000004);
        name_ = getDefaultInstance().getName();
        onChanged();
        return this;
      }
      void setName(com.google.protobuf.ByteString value) {
        bitField0_ |= 0x00000004;
        name_ = value;
        onChanged();
      }
      
      // repeated int32 skills = 4;
      private java.util.List<java.lang.Integer> skills_ = java.util.Collections.emptyList();;
      private void ensureSkillsIsMutable() {
        if (!((bitField0_ & 0x00000008) == 0x00000008)) {
          skills_ = new java.util.ArrayList<java.lang.Integer>(skills_);
          bitField0_ |= 0x00000008;
         }
      }
      public java.util.List<java.lang.Integer>
          getSkillsList() {
        return java.util.Collections.unmodifiableList(skills_);
      }
      public int getSkillsCount() {
        return skills_.size();
      }
      public int getSkills(int index) {
        return skills_.get(index);
      }
      public Builder setSkills(
          int index, int value) {
        ensureSkillsIsMutable();
        skills_.set(index, value);
        onChanged();
        return this;
      }
      public Builder addSkills(int value) {
        ensureSkillsIsMutable();
        skills_.add(value);
        onChanged();
        return this;
      }
      public Builder addAllSkills(
          java.lang.Iterable<? extends java.lang.Integer> values) {
        ensureSkillsIsMutable();
        super.addAll(values, skills_);
        onChanged();
        return this;
      }
      public Builder clearSkills() {
        skills_ = java.util.Collections.emptyList();;
        bitField0_ = (bitField0_ & ~0x00000008);
        onChanged();
        return this;
      }
      
      // @@protoc_insertion_point(builder_scope:PBPlayer)
    }
    
    static {
      defaultInstance = new PBPlayer(true);
      defaultInstance.initFields();
    }
    
    // @@protoc_insertion_point(class_scope:PBPlayer)
  }
  
  public interface PBResourceOrBuilder
      extends com.google.protobuf.MessageOrBuilder {
    
    // required int64 gold = 1;
    boolean hasGold();
    long getGold();
    
    // required int32 energy = 2;
    boolean hasEnergy();
    int getEnergy();
  }
  public static final class PBResource extends
      com.google.protobuf.GeneratedMessage
      implements PBResourceOrBuilder {
    // Use PBResource.newBuilder() to construct.
    private PBResource(Builder builder) {
      super(builder);
    }
    private PBResource(boolean noInit) {}
    
    private static final PBResource defaultInstance;
    public static PBResource getDefaultInstance() {
      return defaultInstance;
    }
    
    public PBResource getDefaultInstanceForType() {
      return defaultInstance;
    }
    
    public static final com.google.protobuf.Descriptors.Descriptor
        getDescriptor() {
      return com.proto.PlayerModule.internal_static_PBResource_descriptor;
    }
    
    protected com.google.protobuf.GeneratedMessage.FieldAccessorTable
        internalGetFieldAccessorTable() {
      return com.proto.PlayerModule.internal_static_PBResource_fieldAccessorTable;
    }
    
    private int bitField0_;
    // required int64 gold = 1;
    public static final int GOLD_FIELD_NUMBER = 1;
    private long gold_;
    public boolean hasGold() {
      return ((bitField0_ & 0x00000001) == 0x00000001);
    }
    public long getGold() {
      return gold_;
    }
    
    // required int32 energy = 2;
    public static final int ENERGY_FIELD_NUMBER = 2;
    private int energy_;
    public boolean hasEnergy() {
      return ((bitField0_ & 0x00000002) == 0x00000002);
    }
    public int getEnergy() {
      return energy_;
    }
    
    private void initFields() {
      gold_ = 0L;
      energy_ = 0;
    }
    private byte memoizedIsInitialized = -1;
    public final boolean isInitialized() {
      byte isInitialized = memoizedIsInitialized;
      if (isInitialized != -1) return isInitialized == 1;
      
      if (!hasGold()) {
        memoizedIsInitialized = 0;
        return false;
      }
      if (!hasEnergy()) {
        memoizedIsInitialized = 0;
        return false;
      }
      memoizedIsInitialized = 1;
      return true;
    }
    
    public void writeTo(com.google.protobuf.CodedOutputStream output)
                        throws java.io.IOException {
      getSerializedSize();
      if (((bitField0_ & 0x00000001) == 0x00000001)) {
        output.writeInt64(1, gold_);
      }
      if (((bitField0_ & 0x00000002) == 0x00000002)) {
        output.writeInt32(2, energy_);
      }
      getUnknownFields().writeTo(output);
    }
    
    private int memoizedSerializedSize = -1;
    public int getSerializedSize() {
      int size = memoizedSerializedSize;
      if (size != -1) return size;
    
      size = 0;
      if (((bitField0_ & 0x00000001) == 0x00000001)) {
        size += com.google.protobuf.CodedOutputStream
          .computeInt64Size(1, gold_);
      }
      if (((bitField0_ & 0x00000002) == 0x00000002)) {
        size += com.google.protobuf.CodedOutputStream
          .computeInt32Size(2, energy_);
      }
      size += getUnknownFields().getSerializedSize();
      memoizedSerializedSize = size;
      return size;
    }
    
    private static final long serialVersionUID = 0L;
    @java.lang.Override
    protected java.lang.Object writeReplace()
        throws java.io.ObjectStreamException {
      return super.writeReplace();
    }
    
    public static com.proto.PlayerModule.PBResource parseFrom(
        com.google.protobuf.ByteString data)
        throws com.google.protobuf.InvalidProtocolBufferException {
      return newBuilder().mergeFrom(data).buildParsed();
    }
    public static com.proto.PlayerModule.PBResource parseFrom(
        com.google.protobuf.ByteString data,
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PB序列化

        //获取一个PBPlayer的构造器
        Builder builder = PlayerModule.PBPlayer.newBuilder();
        //设置数据
        builder.setPlayerId(101).setAge(20).setName("neil").addSkills(1001);
        //构造出对象
        PBPlayer player = builder.build();
        //序列化成字节数组
        byte[] byteArray = player.toByteArray();
        System.out.println(Arrays.toString(byteArray));
        return byteArray;

运行结果, 一串非常短的byte数组, 远远比json, xml, java序列化要短.

[8, 101, 16, 20, 26, 4, 110, 101, 105, 108, 32, -23, 7]

PB反序列化

    public static void toPlayer(byte[] bs) throws Exception{
         PBPlayer player = PlayerModule.PBPlayer.parseFrom(bs);
         System.out.println("playerId:" + player.getPlayerId());
         System.out.println("age:" + player.getAge());
         System.out.println("name:" + player.getName());
         System.out.println("skills:" + (Arrays.toString(player.getSkillsList().toArray())));
    }

运行结果

playerId:101
age:20
name:neil
skills:[1001]

Java序列化

定义player pojo.

    private long playerId;
    private int age;
    private String name;
    private List<Integer> skills = new ArrayList<>();

        Player player = new Player(101, 20, "neil");
        player.getSkills().add(1001);

        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);

        //写入对象
        objectOutputStream.writeObject(player);

        //获取 字节数组
        byte[] byteArray = byteArrayOutputStream.toByteArray();
        System.out.println(Arrays.toString(byteArray));
        return byteArray;

运行结果, 非常长的一个byte数组

[-84, -19, 0, 5, 115, 114, 0, 15, 99, 111, 109, 46, 106, 97, 118, 97, 46, 80, 108, 97, 121, 101, 114, -73, 43, 28, 39, -119, -86, -125, -3, 2, 0, 4, 73, 0, 3, 97, 103, 101, 74, 0, 8, 112, 108, 97, 121, 101, 114, 73, 100, 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, 76, 0, 6, 115, 107, 105, 108, 108, 115, 116, 0, 16, 76, 106, 97, 118, 97, 47, 117, 116, 105, 108, 47, 76, 105, 115, 116, 59, 120, 112, 0, 0, 0, 20, 0, 0, 0, 0, 0, 0, 0, 101, 116, 0, 4, 110, 101, 105, 108, 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, 1, 119, 4, 0, 0, 0, 1, 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, 3, -23, 120]

Java反序列化

        ObjectInputStream inputStream = new ObjectInputStream(new ByteArrayInputStream(bs));
        Player player = (Player)inputStream.readObject();
        
        //打印
         System.out.println("playerId:" + player.getPlayerId());
         System.out.println("age:" + player.getAge());
         System.out.println("name:" + player.getName());
         System.out.println("skills:" + (Arrays.toString(player.getSkills().toArray())));

运行结果

playerId:101
age:20
name:neil
skills:[1001]

对比

经过上面运行结果的对比可以看出来, PB是一个非常高效的序列化协议.

相对于Java这种数据类型固定长度的序列化(int 4字节, long 8字节), PB提供了可伸缩性的数据类型(int 1-5字节).

当数据比较小的时候int只占用1个字节, 而大部分场景下, 数据都是很小的, 不然jdk本身也不会缓存 -127~128了.