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10.2.9 对象流

程序员文章站 2024-03-04 15:32:59
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数据流操作的是基本数据类型和字符串,对象流操控的除了基本数据类型还包括其他的各种对象,以及自定义对象;
ObjectInputStream && ObjectOutputStream
10.2.9 对象流

1 先写出后读取
2 读取的顺序与写出的顺序一致
3 不是所有对象都可以序列化,必须实现serializable接口;
打开API看一下:
ObjectOutputStream:将Java对象的对象和图形写入OutputStream,可以使用ObjectInputStream读取(重构)对象;
下面的代码为具体的应用实例:

package com.sxt.io;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Date;

/**
 * 对象流:
 * 1 写出后读取
 * 2 读取的顺序与写出保持一致
 * 3 不是所有的对象都可以序列化Serializable
 * 
 * ObjectOutputStream
 * ObjectInputStream
 * @author 韩文韬
 *
 */
public class ObjectTest {
	public static void main(String[] args) throws IOException, ClassNotFoundException {
		//写出--序列化
		ByteArrayOutputStream baos=new ByteArrayOutputStream();
		ObjectOutputStream oos=new ObjectOutputStream(new BufferedOutputStream(baos));
		//操作数据类型+数据
		oos.writeUTF("编码辛酸泪");
		oos.writeInt(18);
		oos.writeBoolean(false);
		oos.writeChar('a');
		//加入对象
		oos.writeObject("谁解其中味");
		oos.writeObject(new Date());
		Employee emp=new Employee("马云",400);
		oos.writeObject(emp);
		oos.flush();
		byte[] datas=baos.toByteArray();
		System.out.println(datas.length);
		//读取--反序列化
		ObjectInputStream ois=new ObjectInputStream(new BufferedInputStream(new ByteArrayInputStream(datas)));
		//顺序与写出一致
		String msg=ois.readUTF();
		int age=ois.readInt();
		boolean flag=ois.readBoolean();
		char ch=ois.readChar();
		System.out.println(flag);
		//对象的数据还原
		Object str=ois.readObject();
		Object date=ois.readObject();
		Object employee=ois.readObject();
		
		if(str instanceof String) {
			String strObj=(String)str;
			System.out.println(strObj);
		}
		if(date instanceof Date) {
			Date dateObj=(Date)date;
			System.out.println(dateObj);
		}
		if(employee instanceof Employee) {
			Employee empObj=(Employee)employee;
			System.out.println(empObj.getName()+"-->"+empObj.getSalary());
		}
	}
}
//javabean 封装数据
class Employee implements java.io.Serializable{
	private transient String name;  //transient添加透明效果,表示该数据不需要序列化
	private double salary;
	public Employee(String name, double salary) {
		super();
		this.name = name;
		this.salary = salary;
	}
	public Employee() {
		
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public double getSalary() {
		return salary;
	}
	public void setSalary(double salary) {
		this.salary = salary;
	}
	
}

输出结果为:
143
false
谁解其中味
Fri May 22 15:15:13 CST 2020
null–>400.0
如何写到文件里面去==》go next

package com.sxt.io;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Date;

/**
 * 对象流:
 * 1 写出后读取
 * 2 读取的顺序与写出保持一致
 * 3 不是所有的对象都可以序列化Serializable
 * 
 * ObjectOutputStream
 * ObjectInputStream
 * @author 韩文韬
 *
 */
public class ObjectTest02 {
	public static void main(String[] args) throws IOException, ClassNotFoundException {
		//写出--序列化
		
		ObjectOutputStream oos=new ObjectOutputStream(new BufferedOutputStream(new FileOutputStream("han.txt")));
		//操作数据类型+数据
		oos.writeUTF("编码辛酸泪");
		oos.writeInt(18);
		oos.writeBoolean(false);
		oos.writeChar('a');
		//加入对象
		oos.writeObject("谁解其中味");
		oos.writeObject(new Date());
		Employee emp=new Employee("马云",400);
		oos.writeObject(emp);
		oos.flush();
		oos.close();
		//读取--反序列化
		ObjectInputStream ois=new ObjectInputStream(new BufferedInputStream(new FileInputStream("han.txt")));
		//顺序与写出一致
		String msg=ois.readUTF();
		int age=ois.readInt();
		boolean flag=ois.readBoolean();
		char ch=ois.readChar();
		System.out.println(flag);
		//对象的数据还原
		Object str=ois.readObject();
		Object date=ois.readObject();
		Object employee=ois.readObject();
		
		if(str instanceof String) {
			String strObj=(String)str;
			System.out.println(strObj);
		}
		if(date instanceof Date) {
			Date dateObj=(Date)date;
			System.out.println(dateObj);
		}
		if(employee instanceof Employee) {
			Employee empObj=(Employee)employee;
			System.out.println(empObj.getName()+"-->"+empObj.getSalary());
		}
		ois.close();
	}
	
}
//javabean 封装数据
class Employee implements java.io.Serializable{
	private transient String name;  //transient添加透明效果,表示该数据不需要序列化
	private double salary;
	public Employee(String name, double salary) {
		super();
		this.name = name;
		this.salary = salary;
	}
	public Employee() {
		
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public double getSalary() {
		return salary;
	}
	public void setSalary(double salary) {
		this.salary = salary;
	}
}

由此可以得到han.txt文档中增加了内容;
10.2.9 对象流

相关标签: BAIZHAN课程 java