Java8集合操作详解

Java 8引入了许多新的集合操作，使得对集合的处理更加方便和高效。下面是一些常用的Java 8集合操作的代码示例：

1. 过滤操作

List<String> words = Arrays.asList("hello", "world", "java", "8");

List<String> filteredWords = words.stream()
    .filter(word -> word.length() > 4)
    .collect(Collectors.toList());

System.out.println(filteredWords); // [hello, world]

2. 映射操作

List<String> words = Arrays.asList("hello", "world", "java", "8");

List<Integer> wordLengths = words.stream()
    .map(String::length)
    .collect(Collectors.toList());

System.out.println(wordLengths); // [5, 5, 4, 1]

3. 去重操作

List<Integer> numbers = Arrays.asList(1, 2, 3, 2, 3, 4, 5);

List<Integer> distinctNumbers = numbers.stream()
    .distinct()
    .collect(Collectors.toList());

System.out.println(distinctNumbers); // [1, 2, 3, 4, 5]

4. 排序操作

List<Integer> numbers = Arrays.asList(3, 2, 1, 5, 4);

List<Integer> sortedNumbers = numbers.stream()
    .sorted()
    .collect(Collectors.toList());

System.out.println(sortedNumbers); // [1, 2, 3, 4, 5]

5. 统计操作

List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5);

IntSummaryStatistics stats = numbers.stream()
    .mapToInt(Integer::intValue)
    .summaryStatistics();

System.out.println("Max: " + stats.getMax());
System.out.println("Min: " + stats.getMin());
System.out.println("Sum: " + stats.getSum());
System.out.println("Average: " + stats.getAverage());
System.out.println("Count: " + stats.getCount());

以上是常用的Java 8集合操作的代码示例，这些操作可以帮助我们更加高效地处理集合。