12. Stream 流式计算

什么是 Stream 流式计算

计算都应该交给流来操作！

java.util.stream

// 代码示例
package pers.vincent.matrix.subject.streamdemo;

import java.util.Arrays;
import java.util.List;

public class StreamDemo {

    public static void main(String[] args) {

        User u1 = new User(1, "a", 12);
        User u2 = new User(2, "b", 2);
        User u3 = new User(3, "c", 90);
        User u4 = new User(4, "d", 8);
        User u5 = new User(5, "e", 10);

        List<User> userList = Arrays.asList(u1, u2, u3, u4, u5);

        // 流式计算范例
        userList.stream()
                .filter(u->{return u.getId()%2==0;})
                .map(u->{return u.getName().toUpperCase();})
                .limit(1)
                .forEach(System.out::println);
    }
}