挑战解答：Java 8新特性Stream的运用示例

原创矫情吗；* 2024-11-07 07:18 25阅读 0赞

Java8引入了 Stream API，它提供了对集合对象进行一系列操作的新方式，包括筛选、转换、聚合等。以下是一些使用 Stream 的示例：

###1.基本的 Stream操作```javaimport java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class StreamExample {
 public static void main(String[] args) {
List<String> words = Arrays.asList("apple", "banana", "", "cherry", "strawberry", "", "melon");

//去除空字符串List<String> nonEmptyWords = words.stream()
.filter(word -> !word.isEmpty())
.collect(Collectors.toList());

System.out.println(nonEmptyWords);
 }
}
```###2.排序```javaimport java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class StreamExample {
 public static void main(String[] args) {
List<String> words = Arrays.asList("apple", "banana", "cherry", "strawberry", "melon");

//按字母顺序排序List<String> sortedWords = words.stream()
.sorted()
.collect(Collectors.toList());

System.out.println(sortedWords);
 }
}
```###3.转换```javaimport java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class StreamExample {
 public static void main(String[] args) {
List<String> words = Arrays.asList("apple", "banana", "cherry", "strawberry", "melon");

//将单词转换为大写List<String> uppercasedWords = words.stream()
.map(String::toUpperCase)
.collect(Collectors.toList());

System.out.println(uppercasedWords);
 }
}
```###4.聚合```javaimport java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class StreamExample {
 public static void main(String[] args) {
List<Integer> numbers = Arrays.asList(1,2,3,4,5);

//计算总和int sum = numbers.stream()
.reduce(0, (a, b) -> a + b);

System.out.println("Sum: " + sum);
 }
}
```###5.并行流```javaimport java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class StreamExample {
 public static void main(String[] args) {
List<Integer> numbers = Arrays.asList(1,2,3,4,5,6,7,8,9,10);

//并行流计算总和int sum = numbers.parallelStream()
.reduce(0, (a, b) -> a + b);

System.out.println("Sum: " + sum);
 }
}
```这些示例展示了 Stream API 的基本用法，包括过滤、排序、转换、聚合和并行处理。Stream API 提供了一种声明式的方式来处理集合，使得代码更加简洁和易于理解。