Question

尝试开发一个程序，该程序将搜索给定路径以查找文件（如果用户提供名称或只搜索所有文件），然后查找ext，内容和修改的最后日期。我无法让内容部分正常工作（所以当我进入狗时，我就是其中包含内容的所有文件）＆amp;我还没有开始修改最后修改日期。我一直在尝试使用contains.name，但它无法正常工作。谢谢你的帮助！

现在我的代码现在出现了这个错误。

Main.java:31: error: unreported exception IOException; must be caught or declared to be thrown
               return name.toLowerCase().startsWith(fileN.toLowerCase()) && name.toLowerCase().endsWith("." + ext.toLowerCase()) && find(name, content);
                                                                                                                                        ^
1 error

当我没有抛出我的find方法时，我得到了这个输出：

Search by path, name, extension, content and date.


Enter starting directory for the search (like c:\temp): /Users/KaylaSiemon/Documents
Enter the file name (like myFile or enter for all): 
Enter the file extension (like txt or enter for all): docx
Enter content to search for (like cscd211 or enter for any): kayla
Enter last modified date (like 11/21/2013 or enter for any): kj

java.io.FileNotFoundException: COVER LETTER.docx (No such file or directory)
    at java.io.FileInputStream.open(Native Method)
    at java.io.FileInputStream.<init>(FileInputStream.java:146)
    at java.io.FileInputStream.<init>(FileInputStream.java:101)
    at java.io.FileReader.<init>(FileReader.java:58)
    at Main.find(Main.java:53)
    at Main$1.accept(Main.java:31)
    at java.io.File.list(File.java:1155)
    at Main.main(Main.java:34)

程序代码：

import java.io.*;
import java.util.*;
class Main {
   public static void main(String[] args) throws FileNotFoundException
   {
      Scanner kb = new Scanner(System.in);
      System.out.println("Search by path, name, extension, content and date.\n\n");

      System.out.print("Enter starting directory for the search (like c:" + "\\" + "temp): ");
      String direct = kb.nextLine();
      File dir = new File(direct);

      System.out.print("Enter the file name (like myFile or enter for all): ");
      final String fileN = kb.nextLine();

      System.out.print("Enter the file extension (like txt or enter for all): ");
      final String ext = kb.next();

      System.out.print("Enter content to search for (like cscd211 or enter for any): ");
      final String content = kb.next();

      System.out.print("Enter last modified date (like 11/21/2013 or enter for any): ");
      String date = kb.next();
      System.out.println();
      FilenameFilter filter = 
         new FilenameFilter() {         
            public boolean accept
            (File dir, String name) {
               Scanner input = new Scanner(name);

               return name.toLowerCase().startsWith(fileN.toLowerCase()) && name.toLowerCase().endsWith("." + ext.toLowerCase()) && find(name, content);
            }
         };
      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(dir + "/" +filename);
         }
      }
   }

   public static boolean find(String f, String searchString) throws IOException
   {
      boolean result = false;
      Scanner in = null;

      try
      {
         in = new Scanner(new FileReader(f));

         while(in.hasNextLine() && !result)         {
            result = in.nextLine().indexOf(searchString) >= 0;
         }
      }

      catch(IOException e)
      {
         e.printStackTrace();
      }

      finally
      {
         try
         { 
            in.close(); 
         } 
         catch(Exception e)         { 
         /*ignore*/
         }
      }
      return result;
   }

}

Answer 1

您需要将整个文件IO代码放在以下块中：

try{
    //your code here
}catch(IOException e){
    //code to handle exception if there is a problem with the file
}

Answer 2

Main.java:31: error: unreported exception IOException; must be caught or declared to be thrown
               return name.toLowerCase().startsWith(fileN.toLowerCase()) && name.toLowerCase().endsWith("." + ext.toLowerCase()) && find(name, content);
                                                                                                                                        ^
1 error

告诉你正在调用的方法是抛出IOException，但异常未经处理。它既没有被捕获也没有被重新抛出。

此时您可以将语句包装在try-catch子句中，因为您将无法重新抛出该语句，但更多的调查可能会提供更好的替代方案......

find方法实际上并不需要抛出IOException因为你已经处理过它...但是，我认为这是一个坏主意，因为调用者应该处理例外......赶上22 ......

相反，您的FilenameFilter看起来更像......

FilenameFilter filter
                = new FilenameFilter() {
                    public boolean accept(File dir, String name) {
                        Scanner input = new Scanner(name);

                        boolean accept = false;

                        try {
                            accept = name.toLowerCase().startsWith(fileN.toLowerCase()) && name.toLowerCase().endsWith("." + ext.toLowerCase()) && find(name, content);
                        } catch (IOException e) {
                            e.printStackTrace();
                        }

                        return accept;
                    }
                };

您的find方法更像......

public static boolean find(String f, String searchString) throws IOException {
    boolean result = false;
    Scanner in = null;

    try {
        in = new Scanner(new FileReader(f));

        while (in.hasNextLine() && !result) {
            result = in.nextLine().indexOf(searchString) >= 0;
        }
    } finally {
        try {
            in.close();
        } catch (Exception e) {
            /*ignore*/
        }
    }
    return result;
}

现在...

java.io.FileNotFoundException: COVER LETTER.docx (No such file or directory)
    at java.io.FileInputStream.open(Native Method)
    at java.io.FileInputStream.<init>(FileInputStream.java:146)
    at java.io.FileInputStream.<init>(FileInputStream.java:101)
    at java.io.FileReader.<init>(FileReader.java:58)
    at Main.find(Main.java:53)
    at Main$1.accept(Main.java:31)
    at java.io.File.list(File.java:1155)
    at Main.main(Main.java:34)

是一些事情的结果......

首先，您的FilenameFilter传递了两件事，dir作为File，name作为String。 name仅包含文件的名称，它不包含文件所在的目录，这是dir参数的目的......

其次，您指定了一些任意路径，在本例中为/Users/KaylaSiemon/Documents

第三，程序运行的位置可能与您尝试搜索的路径不一样......

所有这些意味着，当您尝试执行in = new Scanner(new FileReader(f));时，Java实际上是查找文件的当前目录，而不是您之前指定的目录。

也就是说，它不是在寻找/Users/KaylaSiemon/Documents/COVER LETTER.docx，而是在寻找./COVER LETTER.docx

最简单的解决方法是更改find方法的参数以使用File引用而不是String，File提供更好的路径上下文解析String可能......

例如......

public static boolean find(File f, String searchString) throws IOException {

这意味着当您调用它时，您需要将File引用传递给它，例如

find(new File(dir, name), content)

用于在文件中查找文本的Java目录错误

2 个答案: