file的绝对路径

 file的相对路径

 file路径的写法

 

file的各种方法

File.separator 

解决虚拟机和windows路径中的斜杠问题

 lambda怎么写

file1 file2 file3  file4

public class FileDemo04 {
    public static void main(String[] args) {
        File file = new File(".");
        File[] files0 = file.listFiles(new FileFilter() {
            @Override
            public boolean accept(File pathname) {
                if (pathname.getName().startsWith(".")){
                    return true;
                }else {
                    return false;
                }
            }
        });


        File[] files1 = file.listFiles(new Myfile()
        {});
        for (File file1 : files1) {
            System.out.println(file1);
        }


        File[] files2 = file.listFiles(new FileFilter() {
            @Override
            public boolean accept(File pathname) {
                return     pathname.getName().startsWith(".");

            }
        });


        File[] files3 = file.listFiles((pathname) ->pathname.getName().startsWith("."));


        File[] files4 = file.listFiles((pathname)->pathname.getName().startsWith("."));

    }
}

class Myfile implements FileFilter{


    @Override
    public boolean accept(File pathname) {
        if (pathname.getName().endsWith("a")){
            return true;
        }else {
            return false;
        }
    }
}