Stream stream calculation

What is? Stream Flow computation

big data ： Storage + Calculation

aggregate 、Mysql The essence is to store things ;

All calculations should be left to the flow ！

Practice a problem ：

• Subject requirements ： Finish the problem in one minute , It can only be implemented in one line of code ！
• Now by 6 Users ！ Screening ：
• 1、ID It must be an even number
• 2、 Age must be greater than 22 year
• 3、 Change user name to uppercase
• 4、 User names are sorted upside down
• 5、 Output only one user ！

package stream;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

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

/** *  Subject requirements ： Finish the problem in one minute , It can only be implemented in one line of code ！ *  Now by 5 Users ！ Screening ： * 1、ID  It must be an even number  * 2、 Age must be greater than 23 year  * 3、 Change user name to uppercase  * 4、 User names are sorted upside down  * 5、 Output only one user ！ */
public class Test {
    
    public static void main(String[] args) {
    
        User u1 = new User(1, "a", 21);
        User u2 = new User(2, "b", 22);
        User u3 = new User(3, "c", 23);
        User u4 = new User(4, "d", 24);
        User u5 = new User(5, "e", 25);
        User u6 = new User(6, "f", 26);

        // A collection is storage 
        List<User> list = Arrays.asList(u1, u2, u3, u4, u5,u6);
        // The calculation is given to Stream flow 
        list.stream()
                .filter((u)->{
    return u.getId()%2==0;})
                .filter((u)->{
    return u.getAge()>22;})
                .map((u)->{
    return u.getName().toUpperCase();})
                .sorted((uu1,uu2)->{
    return uu2.compareTo(uu1);})
                .limit(1)
                //.forEach(System.out::println);
                .forEach((n)->{
    
                    System.out.println(n);
                });
                //  Three equivalent operations 
                /* for (Object n : list) { System.out.println(n); } list.forEach(n -> System.out.println(n)); list.forEach(System.out::println);*/
    }
}

@Data
@AllArgsConstructor
@NoArgsConstructor
 class User {
    
    private int id;
    private String name;
    private int age;
}