Java如何在正規表示式中匹配重複單詞？

在Java程式設計中，如何在正規表示式中匹配重複單詞？

以下範例顯示了如何使用regex.Matcher類的p.matcher()方法和m.group()方法在正規表示式中搜尋重複的單詞。

package com.yiibai;

import java.util.Scanner;
import java.io.*;
import java.util.regex.*;
import java.util.ArrayList;

public class SearchingDuplicateWords {
    public static void main(String[] args) {
        ArrayList<String> manyLines = new ArrayList<String>();
        ArrayList<String> noRepeat = new ArrayList<String>();
        try {
            String s1 = "Hello hello Hello there there past pastures ";
            Scanner myfis = new Scanner(s1);
            while (myfis.hasNext()) {
                String line = myfis.nextLine();
                String delim = System.getProperty("line.separator");
                String[] lines = line.split(delim);

                for (String s : lines) {
                    if (!s.isEmpty() && s != null) {
                        manyLines.add(s);
                    }
                }
            }
            if (!manyLines.isEmpty()) {
                System.out.print("Original text is:\n");
                for (String s : manyLines) {
                    System.out.println(s);
                }
            }
            if (!manyLines.isEmpty()) {
                for (String s : manyLines) {
                    String result = s.replaceAll("(?i)\\b([a-z]+)\\b(?:\\s+\\1\\b)+", "$1");
                    noRepeat.add(result);
                }
            }
            if (!noRepeat.isEmpty()) {
                System.out.print("After Remove duplicates:\n");
                for (String s : noRepeat) {
                    System.out.println(s);
                }
            }
        } catch (Exception ex) {
            System.out.println(ex);
        }
    }
}

上述程式碼範例將產生以下結果 -

Original text is:
Hello hello Hello there there past pastures 
After Remove duplicates:
Hello there past pastures