3.4 Files

检查文件是否存在 Path path = Paths.get("helloword/data.txt"); System.out.println(Files.exists(path));

创建一级目录 Path path = Paths.get("helloword/d1"); Files.createDirectory(path);

• 如果目录已存在，会抛异常 FileAlreadyExistsException
• 不能一次创建多级目录，否则会抛异常 NoSuchFileException

创建多级目录用

Path path = Paths.get("helloword/d1/d2"); Files.createDirectories(path);

拷贝文件

Path source = Paths.get("helloword/data.txt"); Path target = Paths.get("helloword/target.txt");

Files.copy(source, target);

• 如果文件已存在，会抛异常 FileAlreadyExistsException

如果希望用 source 覆盖掉 target，需要用 StandardCopyOption 来控制

Files.copy(source, target, StandardCopyOption.REPLACE_EXISTING);