javaIO流学习 2019.2.27_什么是import java.io.bufferedinputstream; import jav-优快云博客

本文详细介绍了Java中数据流(DataInputStream/DataOutputStream)和对象流(ObjectInputStream/ObjectOutputStream)的使用方法，包括如何序列化和反序列化各种数据类型及自定义对象，展示了序列化过程中的注意事项。

/*
* 数据流 DataInputStream DataOutputStream
* 1.先写出后读取
* 2.读取的顺序与写出保持一致
*/
public class DataTest {
   public static void main(String[] args)throws IOException {
       //写
       ByteArrayOutputStream baos=new ByteArrayOutputStream();
       DataOutputStream dos=new DataOutputStream(new BufferedOutputStream(baos));
       //操作数据类型+数据
       dos.writeUTF("编码心酸泪");
       dos.writeInt(18);
       dos.writeBoolean(false);
       dos.writeChar('a');
       dos.flush();
       byte[] datas=baos.toByteArray();
       //读
       DataInputStream dis=new DataInputStream(new BufferedInputStream(new ByteArrayInputStream(datas)));
       //顺序和写出保持一致
       String msg=dis.readUTF();
       int age=dis.readInt();
       boolean flag=dis.readBoolean();
       char ch=dis.readChar();
       System.out.println(msg);
   }
}

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

/*
* 对象流 ObjectInputStream ObjectOutputStream
* 1.先写出后读取
* 2.读取的顺序与写出保持一致
* 3.不是所以对象都可以序列化，需要实现空接口Serializable
*/
public class OjectTest {
   public static void main(String[] args)throws IOException, ClassNotFoundException {
       //写-》序列化
       ByteArrayOutputStream baos=new ByteArrayOutputStream();
       ObjectOutputStream dos=new ObjectOutputStream(new BufferedOutputStream(baos));
       //操作数据类型+数据
       dos.writeUTF("编码心酸泪");
       dos.writeInt(18);
       dos.writeBoolean(false);
       dos.writeChar('a');
       //加入对象
       dos.writeObject("谁解其中味");
       dos.writeObject(new Date());
       Employee emp=new Employee("马云",400);
       dos.writeObject(emp);
       dos.flush();
       byte[] datas=baos.toByteArray();
       //读->反序列化
       ObjectInputStream dis=new ObjectInputStream(new BufferedInputStream(new ByteArrayInputStream(datas)));
       //顺序和写出保持一致
       String msg=dis.readUTF();
       int age=dis.readInt();
       boolean flag=dis.readBoolean();
       char ch=dis.readChar();
       System.out.println(msg);
       Object str=dis.readObject();
       Object date=dis.readObject();
       Object employee=dis.readObject();
       if(str instanceof String) {//如果str是String类型的就执行
           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());
       }
   }
}
class Employee implements java.io.Serializable{
   private transient String name;//该数据不需要序列化
   private double salary;

   public Employee() {
       super();
   }

   public Employee(String name, double salary) {
       super();
       this.name = name;
       this.salary = salary;
   }

   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;
   }
}

对象流传文件版

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
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 ObjectInputStream ObjectOutputStream
* 1.先写出后读取
* 2.读取的顺序与写出保持一致
* 3.不是所以对象都可以序列化，需要实现空接口Serializable
*/
public class OjectTest {
   public static void main(String[] args)throws IOException, ClassNotFoundException {
       //写-》序列化
       ObjectOutputStream oos=new ObjectOutputStream(new BufferedOutputStream(new FileOutputStream("c.txt")));
       //操作数据类型+数据
       oos.writeUTF("编码心酸泪");
       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->反序列化
       ObjectInputStream ois=new ObjectInputStream(new BufferedInputStream(new FileInputStream("c.txt")));
       //顺序和写出保持一致
       String msg=ois.readUTF();
       int age=ois.readInt();
       boolean flag=ois.readBoolean();
       char ch=ois.readChar();
       System.out.println(msg);
       Object str=ois.readObject();
       Object date=ois.readObject();
       Object employee=ois.readObject();
       if(str instanceof String) {//如果str是String类型的就执行
           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();
   }
}
class Employee implements java.io.Serializable{
   private transient String name;//该数据不需要序列化
   private double salary;

   public Employee() {
       super();
   }

   public Employee(String name, double salary) {
       super();
       this.name = name;
       this.salary = salary;
   }

   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;
   }


}

import java.io.BufferedOutputStream;
import java.io.FileDescriptor;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;
import java.io.PrintWriter;

/*
* 打印流：PrintWriter
*
*/
public class PrintTest2 {
   public static void main(String[] args)throws FileNotFoundException {

       PrintWriter pw=new PrintWriter(new BufferedOutputStream(new FileOutputStream("Print.txt")),true);
       pw.println("打印流");
       pw.println(true);
       pw.close();

   }
}