File class byte input and output stream

Catalog

1、 Byte output stream ：FileOutputStream

2、 Byte input stream ：FileIntputStream

Running results ：

3、 Byte output stream is used in conjunction with byte input stream ：

result ：

4、 Cache stream ：

  Summary ：

5、 Object flow ：

1. Create an object

2. Create a FileOutputStream object ：

3、 The serialization result is ： 

 4、 Implement deserialization

---

1、 Byte output stream ：FileOutputStream

 @Test
    public void test() throws Exception {
        FileOutputStream fileOutputStream = new FileOutputStream("F:\\111\\1.txt");
        String str="lwh";
        byte[] bytes = str.getBytes();
        fileOutputStream.write(bytes);
        fileOutputStream.close();
    }

Running results ：

2、 Byte input stream ：FileIntputStream

 @Test
    public void test2() throws Exception{
        FileInputStream os = new FileInputStream("F:\\111\\1.txt");
        byte[] bytes = new byte[3];
        int c=0;
        while ((c=os.read(bytes))!=-1){
            String str = new String(bytes,0,c);
            System.out.println(str);
        }

Running results ：

3、 Byte output stream is used in conjunction with byte input stream ：

package demo420.demo02;

import org.junit.Test;

import java.io.*;

/**
 * @ founder  xiaoliu
 * @ Creation time  2022/4/20
 * @ describe 
 */
public class Demo01 {
    @Test
    public void test() throws IOException {
        FileInputStream fos = new FileInputStream("C:\\Users\\Administrator\\Desktop\\1.jpg");
        FileOutputStream os = new FileOutputStream("C:\\Users\\Administrator\\Desktop\\2.jpg");
        byte[] bytes = new byte[5];
        int len;
        while ((len=fos.read(bytes))!=-1) {
            os.write(bytes,0,len);

        }
        fos.close();
        os.close();
    }
}

result ：

4、 Cache stream ：

BufferedInputStream and BufferedOutputStream These two classes are  InputStream and OutputStream Subclasses of , As a subclass of decorator , Use them to prevent every read / Actual write operation when sending data , Represents the use of buffers .

package demo420.demo04;

import org.junit.Test;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;

/**
 * @ founder  xiaoliu
 * @ Creation time  2022/4/21
 * @ describe 
 */
public class DemoBuffer {
    @Test
    public void test() throws Exception{
        FileInputStream is = new FileInputStream("C:\\Users\\Administrator\\Desktop\\111\\6.txt");
        FileOutputStream fos = new FileOutputStream("C:\\Users\\Administrator\\Desktop\\111\\7.txt");
        BufferedOutputStream bos = new BufferedOutputStream(fos);
       int c=0;
        byte[] bytes = new byte[10];
        while ((c=is.read(bytes))!=-1){
            String str = new String(bytes,0,c);
            bos.write(str.getBytes());// byte[] bytes = str.getBytes(); Convert to byte array 
        }
       

    }
}

​

add bos.flush or is.close after , The data will be loaded into the file

bos.flush(); is.close();

​

​

  Summary ：

Only after the stream refresh operation or the stream close operation , Data will be loaded

5、 Object flow ：

java.io.ObjectOutputStream and java.io.ObjectInputStream These two classes can facilitate the serialization of objects (Serialize) And deserialization (Deserialize).

1. Create an object

package demo420.demo03;

import java.io.Serializable;

/**
 * @ founder  xiaoliu
 * @ Creation time  2022/4/20
 * @ describe 
 */
public class Hero implements Serializable {
    private String name;
    private int age;
    private String level;

    public Hero(String name, int age, String level) {
        this.name = name;
        this.age = age;
        this.level = level;
    }

    @Override
    public String toString() {
        return "Hero{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", level='" + level + '\'' +
                '}';
    }
}

2. Create a FileOutputStream object ：

  FileOutputStream is = new FileOutputStream("C:\\Users\\Administrator\\Desktop\\demo.txt");
        ObjectOutputStream os = new ObjectOutputStream(is);
        Hero lwh = new Hero("lwh", 2, "3");
        os.writeObject(lwh);
        os.close();

3、 The serialization result is ： 

 4、 Implement deserialization

Class to implement Serializable Interface

  FileInputStream is = new FileInputStream("C:\\Users\\Administrator\\Desktop\\demo.txt");
        ObjectInputStream objectInputStream = new ObjectInputStream(is);
        Object o = objectInputStream.readObject();
        System.out.println(o);
        is.close();

result ：