FileInputStream||FileOutputStream

package com.sanmao14;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
public class fileoutput {
public static void main(String[] args) throws Exception{
File file=new File("a.txt");
FileOutputStream fileOutputStream=new FileOutputStream(file);//默认 false 追加方式
//FileOutputStream fileOutputStream=new FileOutputStream("a.txt",true);
/**文件不存在就创建，存在就覆盖
*true 追加方式
*false 覆盖方式*/
fileOutputStream.write(65);
/**同一次流输入 多次输入，追加在末尾*/
fileOutputStream.write(" hello".getBytes());
fileOutputStream.close();
byte[] buf=new byte[300];
FileInputStream fileInputStream=new FileInputStream("a.txt");
int a=fileInputStream.read(buf);
System.out.println(new String(buf));
System.out.println(new String(buf,0,2));
fileInputStream.close();
FileOutputStream fileOutputStream=new FileOutputStream("b.txt");
fileOutputStream.write(65);
fileOutputStream.close();
FileInputStream fileInputStream=new FileInputStream("b.txt");
System.out.println(fileInputStream.read());
fileInputStream.close();
byte[] bytes={54,50,66};
FileOutputStream fileOutputStream=new FileOutputStream("b.txt");
fileOutputStream.write(bytes,1,1);
fileOutputStream.close();
FileInputStream fileInputStream=new FileInputStream("b.txt");
System.out.println(fileInputStream.read());
fileInputStream.close();
}
}