JAVA正则表达式替换所有出现的特定单词 "working weird"

Question

有人发现我的这个正则表达式有问题吗？我想要的只是找到任何出现的 并将其替换为用户选择的单词。这个表达式只改变一些出现的情况，当它改变时，它会删除前面的空格，我猜想将它与前面的单词连接起来。而且它也不应该取代 then、there、their、they 等

private final String MY_REGEX = (" the | THE | thE | The | tHe | ThE  ");

        userInput = JTxtInput.getText();
        String usersChoice = JTxtUserChoice.getText();
        String usersChoiceOut = (usersChoice + " ");


        Pattern pattern = Pattern.compile(MY_REGEX, Pattern.CASE_INSENSITIVE);
        Matcher matcher = pattern.matcher(userInput);
        while (matcher.find())
        {
            userInput = userInput.replaceAll(MY_REGEX, usersChoiceOut);
            JTxtOutput.setText(userInput);
            System.out.println(userInput);
        }

好吧，这个新代码似乎取代了所有想要的单词，没有其他任何内容，而且也没有间距问题。

private final String MY_REGEX = ("the |THE |thE |The |tHe |ThE |THe ");
String usersChoiceOut = (usersChoice + " ");

Answer 1

问题是由于 MY_REGEX 中的空格造成的。检查以下演示:

public class Main {
    public static void main(String[] args) {
        String str="This is the eighth wonder of THE world! How about a new style of writing The as tHe";
        // Correct way
        String MY_REGEX = ("the|THE|thE|The|tHe|ThE");
        System.out.println(str.replaceAll(MY_REGEX, "@@@"));
    }
}

输出:

This is @@@ eighth wonder of @@@ world! How about a new style of writing @@@ as @@@

而

public class Main {
    public static void main(String[] args) {
        String str="This is the eighth wonder of THE world! How about a new style of writing The as tHe";
        // Incorrect way
        String MY_REGEX = ("the | THE | thE | The | tHe | ThE");
        System.out.println(str.replaceAll(MY_REGEX, "@@@"));
    }
}

输出:

This is @@@eighth wonder of@@@world! How about a new style of writing@@@as tHe