Java implements file search in a specified directory
The search function of the entry Java implementation file is relatively simple, mainly in the following two types:
1. Give the file name, find whether the directory and its subdirectories exist
2. Give the suffix name, find the related files in the directory and its subdirectories
Question type 1:
Question: Find a file in the specified directory, if there is a file to be found in the directory or subdirectory, return the directory where the file is located, otherwise output "There is no such file in the current directory".
package hello;
import java.io.File;
import java.util.*;
public class 第七周第二题 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner in=new Scanner(System.in);
System.out.println("请输入要查找的文件名:");
String filename=in.nextLine(); //读取要查找的文件名称filename;
File dir=new File("D:\\desktop\\实验七 数据"); //确定要查找的目录dir;
boolean flag=false; //flag来确定是否查到文件;
function(filename,dir,flag); //function函数递归实现;
}
static void function(String filename,File dir,boolean flag)
{
File[]files=dir.listFiles();
for(File file:files)
{
if(file.isDirectory()) //file是目录时,则重新调用function函数;
{
function(filename,file.getAbsoluteFile(),flag);
}
if(file.isFile() && filename.equals(file.getName())) //file时文件且文件名相同时,输出;
{
flag=true;
System.out.println("要查找的文件路径为:"+file.getAbsolutePath());
break;
}
}
if(flag==true) //判断有没有找到过文件;
return;
else
{
System.out.print(dir.getName()+"文件夹下没有找到此文件");
return;
}
}
}
The following is the running result:
Question type 2:
* Determine whether there are files with suffixes .java and .jpg in the specified directory and its subdirectories, if so, output the file name and directory path, if not, output "* There are no .java and .jpg files in the directory".
package hello;
import java.util.*;
import java.io.*;
public class 第八周第一题 {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("指定的目录为:D:\\desktop");
String Filename="D:\\desktop"; //Filename为指定地址;
File file=new File(Filename);
boolean flag=false; //flag判断有没有相关文件;
function(Filename,file,flag);
}
static void function(String Filename,File file,boolean flag)
{
File[]files=file.listFiles();
for(File m:files)
{
if(m.isDirectory()) //m为目录时,调用function函数(更新了绝对路径);
{
function(m.getAbsolutePath(),m.getAbsoluteFile(),flag);
}
if(m.isFile() ) //m为文件时
{
String name=m.getName();
String houzhui=name.lastIndexOf(".")==-1 ? "" : name.substring(name.lastIndexOf(".")+1);//读取其后缀(java还是jpg)
if("java".equals(houzhui)||"jpg".equals(houzhui))//判断后缀是不是java或jpg;
{
System.out.println("文件"+name+"所在的目录为:"+m.getAbsolutePath());//输出文件的绝对路径;
flag=true;
}
}
}
if(flag==true)
return;
else
System.out.println(Filename+"下没有.java和.jpg文件");
}
}
Here is the result of running: