Question

如何将代码中的befferedreader更改为Scanner，因为我不允许使用BufferedReader？或者甚至可能？

public static void Option3Method() throws IOException
{ 
   FileReader fr = new FileReader("wordlist.txt");
   BufferedReader br = new BufferedReader(fr); 
   String s;
   String words[]=new String[500];
   String word = JOptionPane.showInputDialog("Enter a word to search for");
   while ((s=br.readLine())!=null)
   { 
     int indexfound=s.indexOf(word);
     if (indexfound>-1)
     { 
        JOptionPane.showMessageDialog(null, "Word was found");
     }
     else if (indexfound<-1)
     {
        JOptionPane.showMessageDialog(null, "Word was not found");}
     }
     fr.close();
   }
}

Answer 1

替换

FileReader fr = new FileReader("wordlist.txt"); BufferedReader br = new BufferedReader(fr);

与

Scanner scan = new Scanner(new File("wordlist.txt"));

并替换

while ((s=br.readLine())!=null) {

带

while (scan.hasNext()) {

            s=scan.nextLine();
        }

Answer 2

如果查看Scanner类，可以看到它有一个带有File的构造函数，而File又可以用String路径实例化。 Scanner类与readLine（）的方法类似，即nextLine（）。

Answer 3

您可以使用constructor of scanner that takes a file然后使用nextLine()使用该扫描仪读取行。要检查是否有更多行要阅读，请使用hasNextLine()

Answer 4

没有测试它，但它应该工作。

public static void Option3Method() throws IOException
{ 
   Scanner scan = new Scanner(new File("wordlist.txt"));
   String s;
   String words[]=new String[500];
   String word = JOptionPane.showInputDialog("Enter a word to search for");
   while (scan.hasNextLine())
   { 
     s = scan.nextLine();
     int indexfound=s.indexOf(word);
     if (indexfound>-1)
     { 
        JOptionPane.showMessageDialog(null, "Word was found");
     }
     else if (indexfound<-1)
     {
        JOptionPane.showMessageDialog(null, "Word was not found");}
     }
   }
}

文本文件缓冲读卡器

4 个答案: