如何将Array Values作为输出返回给Java中的Method [英] How to return Array Values as a output to a Method in Java

问题描述

我是 Java 的新手。我正在处理上一篇文章 link 。

I am new to Java.I am working on my previous post link.

我想返回特定的扩展名（如 .txt ）目录下的文件名。

I want to return specific extension(like .txt) file names under directory.

为此，我用2个参数编写了以下方法。

For this,I wrote the following method with 2 arguments.

  public void ListOfFileNames(String directoryPath,String fileType)
  {
    //Creating Object for File class
File fileObject=new File(directoryPath);
//Fetching all the FileNames under given Path
File[] listOfFiles=fileObject.listFiles();
//Creating another Array for saving fileNames, which are satisfying as far our requirments
String[] fileNames;
for (int fileIndex = 0; fileIndex < listOfFiles.length; fileIndex++) 
{
    if (listOfFiles[fileIndex].isFile())
    {
        //True condition,Array Index value is File
        if (listOfFiles[fileIndex].getName().endsWith(fileType)) 
        {
            //System.out.println(listOfFiles[fileIndex].getName());
        }
    }
}

}

这里我遇到了2个问题。

Here I am facing 2 problems.

1. 函数返回类型。

1. function return type.

将FileName添加到 fileNames 数组。

Adding FileName into fileNames Array.

我该如何解决这个问题。

How can I fix this.

谢谢。

推荐答案

最好使用List而不是数组

像这样改变你的代码

It is good to use List instead of array
Change your code like this

public void FileMoving()   
{  
   //created object for Class   
   ExternalFileExecutions ExternalFileExecutionsObject=new ExternalFileExecutions();  
   //calling Method from class object
   List<String> fileNames = ExternalFileExecutionsObject.ListOfFileNames("C:/Documents and Settings/mahesh/Desktop/InputFiles",".txt");    
   //to find out the length of list
   System.out.println(fileNames.size());  
}
public List<String> ListOfFileNames(String directoryPath,String fileType)
{
    //Creating Object for File class
    File fileObject=new File(directoryPath);
    //Fetching all the FileNames under given Path
    File[] listOfFiles=fileObject.listFiles();
    //Creating another Array for saving fileNames, which are satisfying as far our requirments
    List<String> fileNames = new ArrayList<String>();
    for (int fileIndex = 0; fileIndex < listOfFiles.length; fileIndex++) 
    {
        if (listOfFiles[fileIndex].isFile())
        {
          //True condition,Array Index value is File
          if (listOfFiles[fileIndex].getName().endsWith(fileType)) 
          {
              //System.out.println(listOfFiles[fileIndex].getName());
              fileNames .add(listOfFiles[fileIndex].getName());
          }
       }
     }  
     return fileNames ;

  }

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