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  • 毕向东_Java基础视频教程第20天_IO流(5~6)

    第20天-05-IO流(文件列表一)

    static File[] listRoots()   

      List the available filesystem roots.

    String[] list()   

      Returns an array of strings naming the files and directories in the directory denoted by this abstract pathname.

    String[] list(FilenameFilter filter)   

      Returns an array of strings naming the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter.

    File[] listFiles()   

      Returns an array of abstract pathnames denoting the files in the directory denoted by this abstract pathname.

    File[] listFiles(FileFilter filter)   

      Returns an array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter.

    File[] listFiles(FilenameFilter filter)   

      Returns an array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter.

    package bxd;
    
    import java.io.File;
    
    public class FileDemo4 {
        public static void method_1() {
            File[] files = File.listRoots();
            for (File file : files) {
                System.out.println(file);
            }
        }
    
        public static void method_2() {
            File dir = new File("/Users/Eric/Desktop");
            // 如果File dir传入的不是目录而是文件, 则会抛出空指针异常
            for (String name : dir.list()) {
                System.out.println(name);
            }
        }
    
        public static void main(String[] args) {
            method_2();
        }
    }

    第20天-06-IO流(文件列表二)

    package bxd;
    
    import java.io.File;
    import java.io.FilenameFilter;
    
    public class FileDemo5 {
        public static void method_1() {
            File demoDir = new File("/Users/Eric/Desktop");
            String[] names = demoDir.list(new FilenameFilter() {
                @Override
                public boolean accept(File dir, String name) {    // accept方法的入参File dir即为File demoDir
                    return name.endsWith(".pdf");
                }
            });
    
            for (String name : names) {
                System.out.println(name);
            }
        }
    
        public static void method_2() {
            File dir = new File("/Users/Eric/Desktop");
            for (File file : dir.listFiles()) {
                System.out.println(file.getName() + "::" + file.length());
            }
        }
    
        public static void main(String[] args) {
            method_2();
        }
    }
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  • 原文地址:https://www.cnblogs.com/echo1937/p/6359029.html
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