如何搜索文件？

Question

据推测，用户将输入他们的"ID #：1203103“，然后将自动创建一个名为1203103.txt的文本文件。如何在文件目录中搜索文件名"1203103.txt“？

String id = scan.nextLine();
File file = new File(id+".txt");
FileWriter fileWrite = new FileWriter(file);
BufferedWriter bufferedWriter = new BufferedWriter(fileWrite);
System.out.println("Enter the ID # to search: ");

Answer 1

你可以试试这个。

import java.io.*;

class Main {
    public static void main(String[] args) {
        File dir = new File("C:"); //file directory
        FilenameFilter filter = new FilenameFilter() {
            public boolean accept(File dir, String name) {
                return name.startsWith("1203103"); //here is you file name starts with. Or you can use name.equals("1203103.txt");
            }
        };
     String[] children = dir.list(filter);
     if (children == null) {
         System.out.println("Either dir does not exist or is not a directory");
     }else {
         for (int i=0; i < children.length; i++) {
             String filename = children[i];
             System.out.println(filename);
         }
     } 
   }
}

希望这能有所帮助。

Answer 2

Scanner scan=new Scanner(System.in);
System.out.println("Enter the ID # to search: ")
String id=scan.next();
File f= new File(id+".txt");
if(f.exists() && !f.isDirectory()) { 
    System.out.println("file exist");
}else{
    System.out.println("file doesn't exist");
}

Answer 3

如果文件不存在，您的代码将创建一个新文件。如果文件确实存在，则将删除该文件，并在其位置创建一个空文件。在这两种情况下，您将有一个全新的空文件。没什么可查的。