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