《Thinking in Java》Chapter 18

《Thinking in Java》Chapter 18

1. 目录列表器

package chapter18;

import java.io.File;
import java.io.FilenameFilter;

import java.util.regex.Pattern;

public class Main {
    private static String fileName = "D:\\Java_Project\\DayProgram\\studyJava";
    public static void main(String[] args) {
        listFile();
        listMatchFile(".*.iml",fileName);//过滤的条件是: .iml结束的文件。注意这个regex的表述
    }

    public static void listFile(){
        System.out.println(fileName+" 下的文件（夹）有：");
        File file = new File(fileName);
        String fileList [] = file.list();
        for (String str : fileList) {
            System.out.println("file name is: "+str );
            //System.out.println("file is a directory:" + );
        }
    }

    public static void listMatchFile(String regex,String dir){
        System.out.println("\n\n匹配的文件有：");
        File file = new File(dir);
        String res []  = file.list(new Filter(regex));
        for(String str : res)
        System.out.println(str);
    }

    public static class Filter implements FilenameFilter {
        private Pattern pattern;

        public Filter(String regex){
            pattern = Pattern.compile(regex);
        }

        public boolean accept(File dir, String name) {
            return pattern.matcher(name).matches();
        }
    }
}

1.2 运行结果

1.3 注意事项

• 正则表达式的表达
• 使用 Pattern 类

2.