JAVA RPC（二）序列化协议杂谈

      序列化和反序列化作为Java里一个较为基础的知识点，大家心里也有那么几句要说的，但我相信很多小伙伴掌握的也就是那么几句而已，如果再深究问一下Java如何实现序列化和反序列化的，就可能不知所措了！遥记当年也被问了这一个问题，自信满满的说了一大堆，什么是序列化、什么是反序列化、什么场景的时候才会用到等，然后面试官说：那你能说一下序列化和反序列化底层是如何实现的吗？一脸懵逼，然后回家等通知！
 

1、什么是序列化和反序列化

（1）Java序列化是指把Java对象转换为字节序列的过程，而Java反序列化是指把字节序列恢复为Java对象的过程；

（2）序列化：对象序列化的最主要的用处就是在传递和保存对象的时候，保证对象的完整性和可传递性。序列化是把对象转换成有序字节流，以便在网络上传输或者保存在本地文件中。序列化后的字节流保存了Java对象的状态以及相关的描述信息。序列化机制的核心作用就是对象状态的保存与重建。

（3）反序列化：客户端从文件中或网络上获得序列化后的对象字节流后，根据字节流中所保存的对象状态及描述信息，通过反序列化重建对象。

（4）本质上讲，序列化就是把实体对象状态按照一定的格式写入到有序字节流，反序列化就是从有序字节流重建对象，恢复对象状态。

2、为什么需要序列化与反序列化

我们知道，当两个进程进行远程通信时，可以相互发送各种类型的数据，包括文本、图片、音频、视频等， 而这些数据都会以二进制序列的形式在网络上传送。

那么当两个Java进程进行通信时，能否实现进程间的对象传送呢？答案是可以的！如何做到呢？这就需要Java序列化与反序列化了！

换句话说，一方面，发送方需要把这个Java对象转换为字节序列，然后在网络上传送；另一方面，接收方需要从字节序列中恢复出Java对象。

当我们明晰了为什么需要Java序列化和反序列化后，我们很自然地会想Java序列化的好处。其好处一是实现了数据的持久化，通过序列化可以把数据永久地保存到硬盘上（通常存放在文件里），二是，利用序列化实现远程通信，即在网络上传送对象的字节序列。

总的来说可以归结为以下几点：

（1）永久性保存对象，保存对象的字节序列到本地文件或者数据库中；
（2）通过序列化以字节流的形式使对象在网络中进行传递和接收；
（3）通过序列化在进程间传递对象；

3、序列化算法一般会按步骤做如下事情：

（1）将对象实例相关的类元数据输出。
（2）递归地输出类的超类描述直到不再有超类。
（3）类元数据完了以后，开始从最顶层的超类开始输出对象实例的实际数据值。
（4）从上至下递归输出实例的数据

4、各种 Java 的序列化库的性能比较测试结果

• 专门针对Java语言的：Kryo，FST等等
• 跨语言的：Protostuff，ProtoBuf，Thrift，Avro，MsgPack等等

图片来源于网络，可以说明对原生序列化来讲，其他三方框架提供的序列化协议要快很多，所以我们做RPC技术选型的时候，序列化协议这块一定要摒弃原生序列化，去选择一款自己熟悉的序列化协议来传输IO流。下面选择做一个thrift序列化和原生序列化的对比结果。

原生序列化user类

package util.dto;

import java.io.Serializable;

public class User implements Serializable {
    private String name;
    private Integer integer;
    private String address;

    public User(String name, Integer integer, String address) {
        this.name = name;
        this.integer = integer;
        this.address = address;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getInteger() {
        return integer;
    }

    public void setInteger(Integer integer) {
        this.integer = integer;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

原生序列化工具类

package util;

import java.io.*;
import java.util.Arrays;

public class SerializeUtil {

    /** 序列化对象
     * ＠throws IOException */
    public static byte[] serializeObject(Object object) throws IOException {
        ByteArrayOutputStream saos = new ByteArrayOutputStream ();
        ObjectOutputStream oos = new ObjectOutputStream(saos);
        oos.writeObject(object);
        oos.flush();
        return saos.toByteArray();
    }

    /** 反序列化对象
     * ＠throws IOException
     * ＠throws ClassNotFoundException */
    public static Object deserializeObject(byte[] buf) throws IOException, ClassNotFoundException{
        Object object=null;
        ByteArrayInputStream sais=new ByteArrayInputStream(buf);
        ObjectInputStream ois = new ObjectInputStream(sais);
        object = ois.readObject();
        return object;
    }
}

由thrift脚本生成的User类

/**
 * Autogenerated by Thrift Compiler (0.8.0)
 *
 * DO NOT EDIT UNLESS YOU ARE SURE THAT YOU KNOW WHAT YOU ARE DOING
 *  @generated
 */
package util.dtothrift;

import org.apache.thrift.scheme.IScheme;
import org.apache.thrift.scheme.SchemeFactory;
import org.apache.thrift.scheme.StandardScheme;

import org.apache.thrift.scheme.TupleScheme;
import org.apache.thrift.protocol.TTupleProtocol;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.util.HashMap;
import java.util.EnumMap;
import java.util.Set;
import java.util.HashSet;
import java.util.EnumSet;
import java.util.Collections;
import java.util.BitSet;
import java.nio.ByteBuffer;
import java.util.Arrays;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class User implements org.apache.thrift.TBase<User, User._Fields>, java.io.Serializable, Cloneable {
  private static final org.apache.thrift.protocol.TStruct STRUCT_DESC = new org.apache.thrift.protocol.TStruct("User");

  private static final org.apache.thrift.protocol.TField STR_FIELD_DESC = new org.apache.thrift.protocol.TField("str", org.apache.thrift.protocol.TType.STRING, (short)1);
  private static final org.apache.thrift.protocol.TField AGE_FIELD_DESC = new org.apache.thrift.protocol.TField("age", org.apache.thrift.protocol.TType.I32, (short)2);
  private static final org.apache.thrift.protocol.TField ADDRESS_FIELD_DESC = new org.apache.thrift.protocol.TField("address", org.apache.thrift.protocol.TType.STRING, (short)3);

  private static final Map<Class<? extends IScheme>, SchemeFactory> schemes = new HashMap<Class<? extends IScheme>, SchemeFactory>();
  static {
    schemes.put(StandardScheme.class, new UserStandardSchemeFactory());
    schemes.put(TupleScheme.class, new UserTupleSchemeFactory());
  }

  public String str; // required
  public int age; // required
  public String address; // required

  /** The set of fields this struct contains, along with convenience methods for finding and manipulating them. */
  public enum _Fields implements org.apache.thrift.TFieldIdEnum {
    STR((short)1, "str"),
    AGE((short)2, "age"),
    ADDRESS((short)3, "address");

    private static final Map<String, _Fields> byName = new HashMap<String, _Fields>();

    static {
      for (_Fields field : EnumSet.allOf(_Fields.class)) {
        byName.put(field.getFieldName(), field);
      }
    }

    /**
     * Find the _Fields constant that matches fieldId, or null if its not found.
     */
    public static _Fields findByThriftId(int fieldId) {
      switch(fieldId) {
        case 1: // STR
          return STR;
        case 2: // AGE
          return AGE;
        case 3: // ADDRESS
          return ADDRESS;
        default:
          return null;
      }
    }

    /**
     * Find the _Fields constant that matches fieldId, throwing an exception
     * if it is not found.
     */
    public static _Fields findByThriftIdOrThrow(int fieldId) {
      _Fields fields = findByThriftId(fieldId);
      if (fields == null) throw new IllegalArgumentException("Field " + fieldId + " doesn't exist!");
      return fields;
    }

    /**
     * Find the _Fields constant that matches name, or null if its not found.
     */
    public static _Fields findByName(String name) {
      return byName.get(name);
    }

    private final short _thriftId;
    private final String _fieldName;

    _Fields(short thriftId, String fieldName) {
      _thriftId = thriftId;
      _fieldName = fieldName;
    }

    public short getThriftFieldId() {
      return _thriftId;
    }

    public String getFieldName() {
      return _fieldName;
    }
  }

  // isset id assignments
  private static final int __AGE_ISSET_ID = 0;
  private BitSet __isset_bit_vector = new BitSet(1);
  public static final Map<_Fields, org.apache.thrift.meta_data.FieldMetaData> metaDataMap;
  static {
    Map<_Fields, org.apache.thrift.meta_data.FieldMetaData> tmpMap = new EnumMap<_Fields, org.apache.thrift.meta_data.FieldMetaData>(_Fields.class);
    tmpMap.put(_Fields.STR, new org.apache.thrift.meta_data.FieldMetaData("str", org.apache.thrift.TFieldRequirementType.DEFAULT, 
        new org.apache.thrift.meta_data.FieldValueMetaData(org.apache.thrift.protocol.TType.STRING)));
    tmpMap.put(_Fields.AGE, new org.apache.thrift.meta_data.FieldMetaData("age", org.apache.thrift.TFieldRequirementType.DEFAULT, 
        new org.apache.thrift.meta_data.FieldValueMetaData(org.apache.thrift.protocol.TType.I32)));
    tmpMap.put(_Fields.ADDRESS, new org.apache.thrift.meta_data.FieldMetaData("address", org.apache.thrift.TFieldRequirementType.DEFAULT, 
        new org.apache.thrift.meta_data.FieldValueMetaData(org.apache.thrift.protocol.TType.STRING)));
    metaDataMap = Collections.unmodifiableMap(tmpMap);
    org.apache.thrift.meta_data.FieldMetaData.addStructMetaDataMap(User.class, metaDataMap);
  }

  public User() {
  }

  public User(
    String str,
    int age,
    String address)
  {
    this();
    this.str = str;
    this.age = age;
    setAgeIsSet(true);
    this.address = address;
  }

  /**
   * Performs a deep copy on <i>other</i>.
   */
  public User(User other) {
    __isset_bit_vector.clear();
    __isset_bit_vector.or(other.__isset_bit_vector);
    if (other.isSetStr()) {
      this.str = other.str;
    }
    this.age = other.age;
    if (other.isSetAddress()) {
      this.address = other.address;
    }
  }

  public User deepCopy() {
    return new User(this);
  }

  @Override
  public void clear() {
    this.str = null;
    setAgeIsSet(false);
    this.age = 0;
    this.address = null;
  }

  public String getStr() {
    return this.str;
  }

  public User setStr(String str) {
    this.str = str;
    return this;
  }

  public void unsetStr() {
    this.str = null;
  }

  /** Returns true if field str is set (has been assigned a value) and false otherwise */
  public boolean isSetStr() {
    return this.str != null;
  }

  public void setStrIsSet(boolean value) {
    if (!value) {
      this.str = null;
    }
  }

  public int getAge() {
    return this.age;
  }

  public User setAge(int age) {
    this.age = age;
    setAgeIsSet(true);
    return this;
  }

  public void unsetAge() {
    __isset_bit_vector.clear(__AGE_ISSET_ID);
  }

  /** Returns true if field age is set (has been assigned a value) and false otherwise */
  public boolean isSetAge() {
    return __isset_bit_vector.get(__AGE_ISSET_ID);
  }

  public void setAgeIsSet(boolean value) {
    __isset_bit_vector.set(__AGE_ISSET_ID, value);
  }

  public String getAddress() {
    return this.address;
  }

  public User setAddress(String address) {
    this.address = address;
    return this;
  }

  public void unsetAddress() {
    this.address = null;
  }

  /** Returns true if field address is set (has been assigned a value) and false otherwise */
  public boolean isSetAddress() {
    return this.address != null;
  }

  public void setAddressIsSet(boolean value) {
    if (!value) {
      this.address = null;
    }
  }

  public void setFieldValue(_Fields field, Object value) {
    switch (field) {
    case STR:
      if (value == null) {
        unsetStr();
      } else {
        setStr((String)value);
      }
      break;

    case AGE:
      if (value == null) {
        unsetAge();
      } else {
        setAge((Integer)value);
      }
      break;

    case ADDRESS:
      if (value == null) {
        unsetAddress();
      } else {
        setAddress((String)value);
      }
      break;

    }
  }

  public Object getFieldValue(_Fields field) {
    switch (field) {
    case STR:
      return getStr();

    case AGE:
      return Integer.valueOf(getAge());

    case ADDRESS:
      return getAddress();

    }
    throw new IllegalStateException();
  }

  /** Returns true if field corresponding to fieldID is set (has been assigned a value) and false otherwise */
  public boolean isSet(_Fields field) {
    if (field == null) {
      throw new IllegalArgumentException();
    }

    switch (field) {
    case STR:
      return isSetStr();
    case AGE:
      return isSetAge();
    case ADDRESS:
      return isSetAddress();
    }
    throw new IllegalStateException();
  }

  @Override
  public boolean equals(Object that) {
    if (that == null)
      return false;
    if (that instanceof User)
      return this.equals((User)that);
    return false;
  }

  public boolean equals(User that) {
    if (that == null)
      return false;

    boolean this_present_str = true && this.isSetStr();
    boolean that_present_str = true && that.isSetStr();
    if (this_present_str || that_present_str) {
      if (!(this_present_str && that_present_str))
        return false;
      if (!this.str.equals(that.str))
        return false;
    }

    boolean this_present_age = true;
    boolean that_present_age = true;
    if (this_present_age || that_present_age) {
      if (!(this_present_age && that_present_age))
        return false;
      if (this.age != that.age)
        return false;
    }

    boolean this_present_address = true && this.isSetAddress();
    boolean that_present_address = true && that.isSetAddress();
    if (this_present_address || that_present_address) {
      if (!(this_present_address && that_present_address))
        return false;
      if (!this.address.equals(that.address))
        return false;
    }

    return true;
  }

  @Override
  public int hashCode() {
    return 0;
  }

  public int compareTo(User other) {
    if (!getClass().equals(other.getClass())) {
      return getClass().getName().compareTo(other.getClass().getName());
    }

    int lastComparison = 0;
    User typedOther = (User)other;

    lastComparison = Boolean.valueOf(isSetStr()).compareTo(typedOther.isSetStr());
    if (lastComparison != 0) {
      return lastComparison;
    }
    if (isSetStr()) {
      lastComparison = org.apache.thrift.TBaseHelper.compareTo(this.str, typedOther.str);
      if (lastComparison != 0) {
        return lastComparison;
      }
    }
    lastComparison = Boolean.valueOf(isSetAge()).compareTo(typedOther.isSetAge());
    if (lastComparison != 0) {
      return lastComparison;
    }
    if (isSetAge()) {
      lastComparison = org.apache.thrift.TBaseHelper.compareTo(this.age, typedOther.age);
      if (lastComparison != 0) {
        return lastComparison;
      }
    }
    lastComparison = Boolean.valueOf(isSetAddress()).compareTo(typedOther.isSetAddress());
    if (lastComparison != 0) {
      return lastComparison;
    }
    if (isSetAddress()) {
      lastComparison = org.apache.thrift.TBaseHelper.compareTo(this.address, typedOther.address);
      if (lastComparison != 0) {
        return lastComparison;
      }
    }
    return 0;
  }

  public _Fields fieldForId(int fieldId) {
    return _Fields.findByThriftId(fieldId);
  }

  public void read(org.apache.thrift.protocol.TProtocol iprot) throws org.apache.thrift.TException {
    schemes.get(iprot.getScheme()).getScheme().read(iprot, this);
  }

  public void write(org.apache.thrift.protocol.TProtocol oprot) throws org.apache.thrift.TException {
    schemes.get(oprot.getScheme()).getScheme().write(oprot, this);
  }

  @Override
  public String toString() {
    StringBuilder sb = new StringBuilder("User(");
    boolean first = true;

    sb.append("str:");
    if (this.str == null) {
      sb.append("null");
    } else {
      sb.append(this.str);
    }
    first = false;
    if (!first) sb.append(", ");
    sb.append("age:");
    sb.append(this.age);
    first = false;
    if (!first) sb.append(", ");
    sb.append("address:");
    if (this.address == null) {
      sb.append("null");
    } else {
      sb.append(this.address);
    }
    first = false;
    sb.append(")");
    return sb.toString();
  }

  public void validate() throws org.apache.thrift.TException {
    // check for required fields
  }

  private void writeObject(java.io.ObjectOutputStream out) throws java.io.IOException {
    try {
      write(new org.apache.thrift.protocol.TCompactProtocol(new org.apache.thrift.transport.TIOStreamTransport(out)));
    } catch (org.apache.thrift.TException te) {
      throw new java.io.IOException(te);
    }
  }

  private void readObject(java.io.ObjectInputStream in) throws java.io.IOException, ClassNotFoundException {
    try {
      // it doesn't seem like you should have to do this, but java serialization is wacky, and doesn't call the default constructor.
      __isset_bit_vector = new BitSet(1);
      read(new org.apache.thrift.protocol.TCompactProtocol(new org.apache.thrift.transport.TIOStreamTransport(in)));
    } catch (org.apache.thrift.TException te) {
      throw new java.io.IOException(te);
    }
  }

  private static class UserStandardSchemeFactory implements SchemeFactory {
    public UserStandardScheme getScheme() {
      return new UserStandardScheme();
    }
  }

  private static class UserStandardScheme extends StandardScheme<User> {

    public void read(org.apache.thrift.protocol.TProtocol iprot, User struct) throws org.apache.thrift.TException {
      org.apache.thrift.protocol.TField schemeField;
      iprot.readStructBegin();
      while (true)
      {
        schemeField = iprot.readFieldBegin();
        if (schemeField.type == org.apache.thrift.protocol.TType.STOP) { 
          break;
        }
        switch (schemeField.id) {
          case 1: // STR
            if (schemeField.type == org.apache.thrift.protocol.TType.STRING) {
              struct.str = iprot.readString();
              struct.setStrIsSet(true);
            } else { 
              org.apache.thrift.protocol.TProtocolUtil.skip(iprot, schemeField.type);
            }
            break;
          case 2: // AGE
            if (schemeField.type == org.apache.thrift.protocol.TType.I32) {
              struct.age = iprot.readI32();
              struct.setAgeIsSet(true);
            } else { 
              org.apache.thrift.protocol.TProtocolUtil.skip(iprot, schemeField.type);
            }
            break;
          case 3: // ADDRESS
            if (schemeField.type == org.apache.thrift.protocol.TType.STRING) {
              struct.address = iprot.readString();
              struct.setAddressIsSet(true);
            } else { 
              org.apache.thrift.protocol.TProtocolUtil.skip(iprot, schemeField.type);
            }
            break;
          default:
            org.apache.thrift.protocol.TProtocolUtil.skip(iprot, schemeField.type);
        }
        iprot.readFieldEnd();
      }
      iprot.readStructEnd();

      // check for required fields of primitive type, which can't be checked in the validate method
      struct.validate();
    }

    public void write(org.apache.thrift.protocol.TProtocol oprot, User struct) throws org.apache.thrift.TException {
      struct.validate();

      oprot.writeStructBegin(STRUCT_DESC);
      if (struct.str != null) {
        oprot.writeFieldBegin(STR_FIELD_DESC);
        oprot.writeString(struct.str);
        oprot.writeFieldEnd();
      }
      oprot.writeFieldBegin(AGE_FIELD_DESC);
      oprot.writeI32(struct.age);
      oprot.writeFieldEnd();
      if (struct.address != null) {
        oprot.writeFieldBegin(ADDRESS_FIELD_DESC);
        oprot.writeString(struct.address);
        oprot.writeFieldEnd();
      }
      oprot.writeFieldStop();
      oprot.writeStructEnd();
    }

  }

  private static class UserTupleSchemeFactory implements SchemeFactory {
    public UserTupleScheme getScheme() {
      return new UserTupleScheme();
    }
  }

  private static class UserTupleScheme extends TupleScheme<User> {

    @Override
    public void write(org.apache.thrift.protocol.TProtocol prot, User struct) throws org.apache.thrift.TException {
      TTupleProtocol oprot = (TTupleProtocol) prot;
      BitSet optionals = new BitSet();
      if (struct.isSetStr()) {
        optionals.set(0);
      }
      if (struct.isSetAge()) {
        optionals.set(1);
      }
      if (struct.isSetAddress()) {
        optionals.set(2);
      }
      oprot.writeBitSet(optionals, 3);
      if (struct.isSetStr()) {
        oprot.writeString(struct.str);
      }
      if (struct.isSetAge()) {
        oprot.writeI32(struct.age);
      }
      if (struct.isSetAddress()) {
        oprot.writeString(struct.address);
      }
    }

    @Override
    public void read(org.apache.thrift.protocol.TProtocol prot, User struct) throws org.apache.thrift.TException {
      TTupleProtocol iprot = (TTupleProtocol) prot;
      BitSet incoming = iprot.readBitSet(3);
      if (incoming.get(0)) {
        struct.str = iprot.readString();
        struct.setStrIsSet(true);
      }
      if (incoming.get(1)) {
        struct.age = iprot.readI32();
        struct.setAgeIsSet(true);
      }
      if (incoming.get(2)) {
        struct.address = iprot.readString();
        struct.setAddressIsSet(true);
      }
    }
  }

}

测试类

package util;

import org.apache.thrift.TException;
import org.apache.thrift.protocol.TBinaryProtocol;
import org.apache.thrift.transport.TIOStreamTransport;
import org.apache.thrift.transport.TSocket;
import org.apache.thrift.transport.TTransport;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import util.dto.User;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Arrays;

public class SerializeTest {

    private final static Logger logger = LoggerFactory.getLogger ( SerializeTest.class );

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

        long a = System.currentTimeMillis ();
        for (int i = 0; i < 100000; i++) {
            User user = new User("姓名"+i,i,"北京市海淀区中关村大厦"+i);
            byte[] b = SerializeUtil.serializeObject ( user );
            //System.out.println (Arrays.toString ( b ));
            User user1 = (User) SerializeUtil.deserializeObject ( b );
        }
        System.out.println (System.currentTimeMillis ()-a);

        long b = System.currentTimeMillis ();

        for (int i = 0; i < 100000; i++) {
            util.dtothrift.User user = new util.dtothrift.User("姓名"+i,i,"北京市海淀区中关村大厦"+i);
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            TTransport transport = new TIOStreamTransport (out);
            TBinaryProtocol tp = new TBinaryProtocol(transport);
            try {
                user.write(tp);
            } catch (TException e) {
                e.printStackTrace();
            }
            byte[] bytes = out.toByteArray();
            //System.out.println ( Arrays.toString ( bytes ));
            util.dtothrift.User user1 = new util.dtothrift.User();

            ByteArrayInputStream bis = new ByteArrayInputStream (  bytes);
            TTransport transport1 = new TIOStreamTransport(bis);
            TBinaryProtocol tp1 = new TBinaryProtocol(transport1);
            user1.read (tp1);
        }
        System.out.println (System.currentTimeMillis ()-b);
    }

}

10万次序列化和反序列化的结果对比

由上图可以看出，采用facebook的序列化协议要比原生jdk序列化协议在10万次序列化和反序列化操作中的时间快很多，并且thrift没有原生序列化的那么多的要求，我们来看看原生序列化和thrift序列化的输入结果都是什么，打开 System.out.println ( Arrays.toString ( bytes ))代码后

jdk 输出流

[-84, -19, 0, 5, 115, 114, 0, 13, 117, 116, 105, 108, 46, 100, 116, 111, 46, 85, 115, 101, 114, -45, 124, 21, -36, 14, -39, -44, 35, 2, 0, 3, 76, 0, 7, 97, 100, 100, 114, 101, 115, 115, 116, 0, 18, 76, 106, 97, 118, 97, 47, 108, 97, 110, 103, 47, 83, 116, 114, 105, 110, 103, 59, 76, 0, 7, 105, 110, 116, 101, 103, 101, 114, 116, 0, 19, 76, 106, 97, 118, 97, 47, 108, 97, 110, 103, 47, 73, 110, 116, 101, 103, 101, 114, 59, 76, 0, 4, 110, 97, 109, 101, 113, 0, 126, 0, 1, 120, 112, 116, 0, 34, -27, -116, -105, -28, -70, -84, -27, -72, -126, -26, -75, -73, -26, -73, -128, -27, -116, -70, -28, -72, -83, -27, -123, -77, -26, -99, -111, -27, -92, -89, -27, -114, -90, 48, 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, 0, 116, 0, 7, -27, -89, -109, -27, -112, -115, 48]

thrift输出流

[11, 0, 1, 0, 0, 0, 7, -27, -89, -109, -27, -112, -115, 48, 8, 0, 2, 0, 0, 0, 0, 11, 0, 3, 0, 0, 0, 34, -27, -116, -105, -28, -70, -84, -27, -72, -126, -26, -75, -73, -26, -73, -128, -27, -116, -70, -28, -72, -83, -27, -123, -77, -26, -99, -111, -27, -92, -89, -27, -114, -90, 48, 0]

由此可以看出jdk的输出流比thrift的输出流多很多，因为jdk原生序列化对方法栈信息，类信息等做了详细的记录，其实这些信息对于RPC来说不是传输必要参数，所以精简序列化IO流大小在传输中十分关键

本章对序列化进行了简单的概述，大家可以针对我的上面代码进行测试。

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koalas rpc源码地址https://gitee.com/a1234567891/koalas-rpc