使扫描仪读取文本文件

Question

I am trying to use a scanner to read a text file pulled with JFileChooser . The wordCount is working correctly, so I know it is reading. However, I cannot get it to search for instances of the user inputted word.

public static void main(String[] args) throws FileNotFoundException {
    String input = JOptionPane.showInputDialog("Enter a  word");
    JFileChooser fileChooser = new JFileChooser();
    fileChooser.showOpenDialog(null);
    File fileSelection = fileChooser.getSelectedFile();
    int wordCount = 0;
    int inputCount = 0;
    Scanner s = new Scanner (fileSelection);
    while (s.hasNext()) {
        String word = s.next();
        if (word.equals(input)) {
            inputCount++;
    }
    wordCount++;
}

Answer 1

如果用户输入的文本大小写不同，则应尝试使用equalsIgnoreCase()

Answer 2

除了blackpanthers答案，您还应该使用trim（）来解决空白问题。as“ abc”不等于“ abc”

Answer 3

You'll have to look for

, ; . ! ? etc.

for each word. The next() method grabs an entire string until it hits an empty space .

It will consider "hi, how are you?" as the following "hi,", "how", "are", "you?".

You can use the method indexOf(String) to find these characters. You can also use replaceAll(String regex, String replacement) to replace characters. You can individuality remove each character or you can use a Regex , but those are usually more complex to understand.

//this will remove a certain character with a blank space
word = word.replaceAll(".","");
word = word.replaceAll(",","");
word = word.replaceAll("!","");
//etc.

Read more about this method:

http://docs.oracle.com/javase/6/docs/api/java/lang/String.html#replaceAll%28java.lang.String,%20java.lang.String%29

Here's a Regex example:

//NOTE:  This example will not work for you.  It's just a simple example for seeing a Regex.
//Removes whitespace between a word character and . or ,
String pattern = "(\\w)(\\s+)([\\.,])";
word = word.replaceAll(pattern, "$1$3"); 

Source:

http://www.vogella.com/articles/JavaRegularExpressions/article.html

Here is a good Regex example that may help you:

Regex for special characters in java

Parse and remove special characters in java regex

Remove all non-"word characters" from a String in Java, leaving accented characters?

Answer 4

You should take a look at matches() .

equals will not help you, since next() doesn't return the file word by word, but rather whitespace ( not comma, semicolon, etc.) separated token by token (as others mentioned).

Here the java doc
String#matches(java.lang.String)

...and a little example.

input = ".*" + input + ".*";
...
boolean foundWord = word.matches(input)

. is the regex wildcard and stands for any sign. .* stands for 0 or more undefined signs. So you get a match, if input is somewhere in word .