输出outputStream、

import java.io.FileOutputStream;
import java.io.IOException;


public class DemoOutputStream {

    public static void main(String[] args) throws IOException {
        FileOutputStream fileOutputStream = new FileOutputStream("D:\学习\a.txt");
        fileOutputStream.write(99);
        fileOutputStream.close();


    }
}

import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Arrays;


public class DemoOutputStream01 {
    public static void main(String[] args) throws IOException {
        FileOutputStream fileOutputStream =new FileOutputStream("D:\学习\b.txt");
        byte[]bytes={ 65,66,67,68};
        fileOutputStream.write(bytes);
        fileOutputStream.write(bytes,1,2);
        //getBytes 把字符串转换为字节数组
        byte[] bytes1 ="你好".getBytes();
        System.out.println(Arrays.toString(bytes1));
        fileOutputStream.write(bytes1);
        fileOutputStream.close();
    }
}