Java序列化与反序列化
首先解释两个概念,何为序列化?何为反序列化?
序列化:将对象转化成流的过程称为序列化
反序列化:将流转化成对象的过程称之为反序列化
序列化与反序列化必须遵守的原则
a) Java对象
在java中要想使一个java对象可以实现序列化与反序列化,必须让该类实现java.io.Serializable接口
java.io.Serializable接口定义如下:
publicinterface Serializable {
}
从上述定义中可以看到该接口中未定义任何方法,这大大的简化了开发者
b) 序列化主要依赖java.io.ObjectOutputStream类,该类对java.io.FileOutputStream进一步做了封装,这里主要使用ObjectOutputStream类的writeObject()方法实现序列化功能
Demo:
/**
*将对象序列化到磁盘文件中
*@paramo
*@throwsException
*/
publicstaticvoid writeObject(Object o) throws Exception{
File f=new File("d:""user.tmp");
if(f.exists()){
f.delete();
}
FileOutputStream os=new FileOutputStream(f);
//ObjectOutputStream 核心类
ObjectOutputStream oos=new ObjectOutputStream(os);
oos.writeObject(o);
oos.close();
os.close();
}
c) 反序列化主要依赖java.io.ObjectInputStream类,该类对java.io.InputStream进一步做了封装,这里主要使用ObjectInputStream类的readObject()方法实现序列化功能
Demo:
/**
*反序列化,将磁盘文件转化为对象
*@paramf
*@return
*@throwsException
*/
publicstatic User readObject(File f) throws Exception{
InputStream is=new FileInputStream(f);
//ObjectOutputStream 核心类
ObjectInputStream ois=new ObjectInputStream(is);
return (User)ois.readObject();
}
贴出完整的demo
Java对象:
package com.io.bean;
importjava.io.Serializable;
publicclass User implementsSerializable {
privateintuserId;
private String userName;
private String userSex;
privateintuserAge;
publicint getUserAge() {
returnuserAge;
}
publicvoid setUserAge(int userAge) {
this.userAge = userAge;
}
publicint getUserId() {
returnuserId;
}
publicvoid setUserId(int userId) {
this.userId = userId;
}
public String getUserName() {
returnuserName;
}
publicvoid setUserName(String userName) {
this.userName = userName;
}
public String getUserSex() {
returnuserSex;
}
publicvoid setUserSex(String userSex) {
this.userSex = userSex;
}
@Override
public String toString() {
returnthis.getUserId() + " " + this.getUserName() + " "
+ this.getUserSex() + " " + this.getUserAge();
}
}
序列化与反序列化
package com.io.test;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import com.io.bean.User;
publicclass TestSerializable {
/**
*将对象序列化到磁盘文件中
*@paramo
*@throwsException
*/
publicstaticvoid writeObject(Object o) throws Exception{
File f=new File("d:""user.tmp");
if(f.exists()){
f.delete();
}
FileOutputStream os=new FileOutputStream(f);
//ObjectOutputStream 核心类
ObjectOutputStream oos=new ObjectOutputStream(os);
oos.writeObject(o);
oos.close();
os.close();
}
/**
*反序列化,将磁盘文件转化为对象
*@paramf
*@return
*@throwsException
*/
publicstatic User readObject(File f) throws Exception{
InputStream is=new FileInputStream(f);
//ObjectOutputStream 核心类
ObjectInputStream ois=new ObjectInputStream(is);
return (User)ois.readObject();
}
publicstaticvoid main(String[] args) throws Exception{
/*****************将对象序列化***************/
/*
User user=new User();
user.setUserId(1);
user.setUserName("张艺谋");
user.setUserSex("男");
user.setUserAge(50);
TestSerializable.writeObject(user);
*/
/*****************将对象序反列化***************/
User user=TestSerializable.readObject(new File("d:""user.tmp"));
System.out.println(user);
}
}