请改用stream流来实现刚才的功能

以下是使用Java 8中的Stream流来实现刚才的功能的示例代码：

import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class Main {
    public static void main(String[] args) {
        List<String> words = Arrays.asList("hello", "world", "java", "programming", "language");

        // 找出长度大于等于5的单词
        List<String> longWords = words.stream()
                .filter(word -> word.length() >= 5)
                .collect(Collectors.toList());
        System.out.println("长单词：" + longWords);

        // 将单词转换为大写形式
        List<String> upperCaseWords = words.stream()
                .map(String::toUpperCase)
                .collect(Collectors.toList());
        System.out.println("大写单词：" + upperCaseWords);

        // 计算所有单词的总长度
        int totalLength = words.stream()
                .mapToInt(String::length)
                .sum();
        System.out.println("单词总长度：" + totalLength);
    }
}

输出：

长单词：[hello, world, programming, language]
大写单词：[HELLO, WORLD, JAVA, PROGRAMMING, LANGUAGE]
单词总长度：33