Java8中Stream常用方法findFirst()和findAny()的示例分享

下文笔者讲述Stream中findFirst和findAny方法的示例分享,如下所示

findFirst和findAny方法简介

findFirst():
   返回Stream中第一个元素
findAny():
    返回Stream中的任何元素(只返回一个元素)

例:findFirst和findAny方法的示例

Java8FindFirstTest.java

package com.java265.java8;
 
import java.util.Arrays;
import java.util.list;
import java.util.Optional;
 
public class Java8FindFirstTest {
 
    public static void main(String[] args) {
 
        List<Integer> list = Arrays.asList(8,10,323,123,12,444);
 
        Optional<Integer> first = list.stream().findFirst();
        if (first.isPresent()) {
            Integer result = first.get();
            System.out.println(result);       // 8
        } else {
            System.out.println("no value?");
        }
 
        Optional<Integer> first2 = list
                .stream()
                .filter(x -> x > 100).findFirst();
 
        if (first2.isPresent()) {
            System.out.println(first2.get()); // 323
        } else {
            System.out.println("no value?");
        }
    }
 
}

findAny()

 
package com.java265.java8;
 
import java.util.Arrays;
import java.util.List;
import java.util.Optional;
 
public class Java8FindAnyTest {
 
    public static void main(String[] args) {
 
        List<Integer> list = Arrays.asList(33,11,2324,888,23232);
 
        Optional<Integer> any = list.stream().filter(x -> x > 1).findAny();
        if (any.isPresent()) {
            Integer result = any.get();
            System.out.println(result);
        }
 
    }
 
}