Java 中的谓词

Java中的谓词是一种用于表示逻辑条件的接口。它可以用来描述一个对象是否满足特定的条件，从而实现对数据集合的筛选和过滤。在Java中，谓词通常被用于集合操作，例如对集合元素进行筛选、排序或映射等。本文将介绍Java中的谓词接口，以及如何使用它进行集合操作。

java
@FunctionalInterface
public interface Predicate {
    boolean test(T t);
}

java
List numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
Predicate isEven = number -> number % 2 == 0;
List evenNumbers = numbers.stream()
                                   .filter(isEven)
                                   .collect(Collectors.toList());
System.out.println(evenNumbers);  // 输出 [2, 4, 6, 8, 10]

java
List names = Arrays.asList("Alice", "Bob", "Charlie", "David", "Eve");
Predicate startsWithA = name -> name.startsWith("A");
Predicate endsWithE = name -> name.endsWith("e");
List filteredNames = names.stream()
                                  .filter(startsWithA.and(endsWithE))
                                  .collect(Collectors.toList());
System.out.println(filteredNames);  // 输出 [Alice]

java
import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;
import java.util.stream.Collectors;
public class PredicateExample {
    public static void main(String[] args) {
        List numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
        Predicate isEven = number -> number % 2 == 0;
        List evenNumbers = numbers.stream()
                                           .filter(isEven)
                                           .collect(Collectors.toList());
        System.out.println(evenNumbers);  // 输出 [2, 4, 6, 8, 10]
        List names = Arrays.asList("Alice", "Bob", "Charlie", "David", "Eve");
        Predicate startsWithA = name -> name.startsWith("A");
        Predicate endsWithE = name -> name.endsWith("e");
        List filteredNames = names.stream()
                                          .filter(startsWithA.and(endsWithE))
                                          .collect(Collectors.toList());
        System.out.println(filteredNames);  // 输出 [Alice]
    }
}