java中的序列化

红太狼 2022-06-03 05:43 196阅读 0赞

[序列化][Link 1] 就是一种用来处理对象流的 [机制][Link 2] ，所谓对象流也就是将对象的内容进行 [流化][Link 3] 。可以对流化后的对象进行读写操作，也可将流化后的对象传输于网络 [之间][Link 4] 。序列化是为了解决在对对象流进行读写操作时所引发的问题。  
序列化的实现：将需要被序列化的类实现 [Serializable接口][Serializable] ，该接口没有需要实现的方法，implements Serializable只是为了标注该对象是可被序列化的，然后使用一个输出流(如：FileOutputStream)来构造一个 ObjectOutputStream(对象流)对象，接着，使用ObjectOutputStream对象的writeObject(Object obj)方法就可以将 [参数][Link 5] 为obj的对象写出(即保存其状态)，要恢复的话则用输入流。

简单来说 序列化就是把Java对象储存在某一地方（硬盘、网络），以便于传输。

代码示例：

package com.java.oop119;
    
    import java.io.Serializable;
    
    public class GirlFriend implements Serializable {
    	private String name;
    	private int age;
    
    	public GirlFriend(String name, int age) {
    		super();
    		this.name = name;
    		this.age = age;
    	}
    
    	public GirlFriend() {
    		super();
    	}
    
    	public String getName() {
    		return name;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    	public int getAge() {
    		return age;
    	}
    
    	public void setAge(int age) {
    		this.age = age;
    	}
    
    	@Override
    	public String toString() {
    		return "GirlFrien [name=" + name + ", age=" + age + "]";
    	}
    
    }

package com.java.oop119;
    
    import java.io.Serializable;
    //类通过实现 java.io.Serializable 接口以启用其序列化功能。未实现此接口的类将无法使其任何状态序列化或反序列化。
    //可序列化类的所有子类型本身都是可序列化的。序列化接口没有方法或字段，仅用于标识可序列化的语义。
    
    public class Man implements Serializable {
    	private String name;
    	private int age;
    	private GirlFriend girl;
    
    	public Man(String name, int age, GirlFriend girl) {
    		super();
    		this.name = name;
    		this.age = age;
    		this.girl = girl;
    	}
    
    	public Man() {
    		super();
    	}
    
    	public String getName() {
    		return name;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    	public int getAge() {
    		return age;
    	}
    
    	public void setAge(int age) {
    		this.age = age;
    	}
    
    	public GirlFriend getGirl() {
    		return girl;
    	}
    
    	public void setGirl(GirlFriend girl) {
    		this.girl = girl;
    	}
    
    	@Override
    	public String toString() {
    		return "Man [name=" + name + ", age=" + age + ", girl=" + girl + "]";
    	}
    
    }

package com.java.oop119;
    
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.ObjectInputStream;
    import java.io.ObjectOutputStream;
    import java.util.ArrayList;
    import java.util.List;
    
    public class Test {
    	public static void main(String[] args) {
    		Man m1 = new Man("小强", 20, new GirlFriend("小花", 18));
    		Man m2 = new Man("英雄", 28, new GirlFriend("美女", 20));
    		Man m3 = new Man( "校草", 22, new GirlFriend("校花", 17));
    		FileOutputStream out =null;//对象流输入到文件
    		ObjectOutputStream objOut=null;//对象输入流成对出现
    		
    		FileInputStream in = null;//从文件中读取到工程
    		ObjectInputStream objIn =null;
    		try {
    			out = new FileOutputStream("man/man.properties");
    			objOut = new ObjectOutputStream(out);
    			
    			in = new FileInputStream("man/man.properties");
    			objIn = new ObjectInputStream(in);
    			
    			List<Man> lit  =new ArrayList<Man>();
    			lit.add(m1);
    			lit.add(m2);
    			lit.add(m3);
    			objOut.writeObject(lit);//输入对象到文件中
    			List<Man> newLit = (List<Man>) objIn.readObject();//从文件中输入存储到新集合中
    			System.out.println(newLit);
    			
    			objOut.flush();//刷新输出流
    		} catch (FileNotFoundException e) {
    			e.printStackTrace();
    		} catch (IOException e) {
    			e.printStackTrace();
    		} catch (ClassNotFoundException e) {
    			e.printStackTrace();
    		}finally{
    			try {
    				if(objIn!=null){
    					objIn.close();	
    				}
    				if(objOut!=null){
    					objOut.close();
    				}
    			} catch (IOException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    		}
    			
    	}
    }

import java.io.FileOutputStream;
    import java.io.IOException;
    import java.util.Properties;
    
    
    public class Learn1 {
    	public static void main(String[] args) {
    		//Properties
    		Properties pro = new Properties();
    
    		// 增--注意键值对都是String类型
    		pro.setProperty("MrLi", "666");
    		pro.setProperty("small pang!", "2333");
    		pro.setProperty("big pang!", "I No care~");
    		System.out.println(pro);
    
    		// 删--remove(键)，如果有则删除，如果没有则没有效果
    		pro.remove("小黎1");
    		System.out.println(pro);
    
    		// 查--getProperty(键) 得到键的值，如果没有该键，则返回null
    		String str = pro.getProperty("小黎1");
    		System.out.println(str);
    
    		// 改--同样使用setProperty()方法
    		pro.setProperty("MrLi", "6666");
    		System.out.println(pro);
    
    		try {
    			pro.store(new FileOutputStream("test/xiaoli.properties"), null);
    			System.out.println("存储成功");
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    }

[Link 1]: http://www.so.com/s?q=%E5%BA%8F%E5%88%97%E5%8C%96&ie=utf-8&src=internal_wenda_recommend_textn
[Link 2]: http://www.so.com/s?q=%E6%9C%BA%E5%88%B6&ie=utf-8&src=internal_wenda_recommend_textn
[Link 3]: http://www.so.com/s?q=%E6%B5%81%E5%8C%96&ie=utf-8&src=internal_wenda_recommend_textn
[Link 4]: http://www.so.com/s?q=%E4%B9%8B%E9%97%B4&ie=utf-8&src=internal_wenda_recommend_textn
[Serializable]: http://www.so.com/s?q=Serializable%E6%8E%A5%E5%8F%A3&ie=utf-8&src=internal_wenda_recommend_textn
[Link 5]: http://www.so.com/s?q=%E5%8F%82%E6%95%B0&ie=utf-8&src=internal_wenda_recommend_textn