File文件类

创建文件

File file = new File("D:\\file_test\\c.txt");

if(!file.exists()) {
    
    File parentFile = file.getParentFile();
    
    if(!parentFile.exists()) {
        boolean mkdirs = parentFile.mkdirs();
        System.out.println(mkdirs);
    }
    
    boolean createNewFile = file.createNewFile();
    
    System.out.println(createNewFile);
    
}

递归文件：

public static void digui(File file) {
	File[] files = file.listFiles();
	if(file.isDirectory()) {
		System.out.println("Directory==="+file.getName());
		for (int i = 0; i < files.length; i++) {
			if(file.isDirectory()) {
				digui(files[i]);
			}
		}
	}else {
		System.out.println("File==="+file.getName());
	}
}

写数据

String str = "1,3,5,7,9,2,4,6,8,10";

FileWriter fw = new FileWriter(file);

fw.write(str);

fw.flush();

fw.close();

读数据：

FileReader fr = new FileReader(file);

BufferedReader br = new BufferedReader(fr);

StringBuffer sb = new StringBuffer();

while(br.ready()) {
	sb.append(br.readLine());
}

br.close();
fr.close();

System.out.println(sb.toString().trim());