[Java知识库]File类，输入输出流用法

package com.heima.test;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class FileOutputTest {
    public static void main(String[] args) throws IOException {
        //路径有就可以，fos.txt文件自动创建
        File file = new File("C:\\Users\\U000000\\Desktop\\file\\fos.txt");
        //false全部清空
        FileOutputStream fos = new FileOutputStream(file,true);
        // 写出数据C:\Users\U100926\Desktop
        String s = System.lineSeparator();
        byte[] b1 = ("1234"+s).getBytes();

        byte[] b2 = "1234\r\n".getBytes();
        System.lineSeparator();

        fos.write(97); // 写出第1个字节
        fos.write(98); // 写出第2个字节
        fos.write(121); // 写出第3个字节
        fos.write(b2);
        // 关闭资源
        fos.close();
    }
}

用java删除文件

package com.heima.test;

import java.io.File;

public class DeleteFile {
    public static void main(String[] args) {
        String dir = "C:\\Users\\U00000\\Desktop\\file\\fos.txt";
        boolean success = (new File(dir)).delete();
        if (success) {
            System.out.println("Successfully deleted empty directory: " + dir);
        } else {
            System.out.println("Failed to delete empty directory: " + dir);
        }
    }
}