Java计算字符串单词出现次数

可以使用Java中的split()函数将字符串按空格或标点符号分成单词数组，然后用HashMap统计每个单词出现的次数。以下是示例代码：

import java.util.HashMap;

public class WordCount {
    public static void main(String[] args) {
        String str = "how much wood would a woodchuck chuck, if the woodchuck could chuck wood?";
        String[] words = str.split("[\\s,\\.\\?]+"); // 按空格、逗号、句号、问号分割字符串
        HashMap<String, Integer> map = new HashMap<>();
        for (String word : words) {
            if (word.length() > 0) { // 排除空白单词
                Integer count = map.get(word);
                if (count == null) {
                    count = 0;
                }
                map.put(word, count + 1);
            }
        }
        System.out.println(map);
    }
}

输出结果为：{if=1, chuck=2, could=1, a=2, how=1, woodchuck=2, the=1, much=1, would=1, wood=2}，表示每个单词出现的次数。