List集合排序Demo

import com.google.common.collect.Lists;
import lombok.AllArgsConstructor;
import lombok.NoArgsConstructor;

import java.util.*;

/**
 * list order demo
 */
public class ListOrderDemo {

    public static void main(String[] args) {
        List<String> list = Lists.newArrayList("1","3","2");

        // convert to array
        String[] array = list.toArray(new String[]{});
        // [1, 3, 2]
        System.out.println(Arrays.toString(array));

        /** order asc **/
        // [1, 2, 3]
        list.sort(String::compareTo);
        System.out.println(list);

        // [1, 2, 3]
        list.sort((o1, o2) -> o1.compareTo(o2));
        System.out.println(list);

        // [1, 2, 3]
        list.sort(new Comparator<String>() {
            @Override
            public int compare(String o1, String o2) {
                return o1.compareTo(o2);
            }
        });
        System.out.println(list);

        /** order desc **/
        // [3, 2, 1]
        list.sort(Comparator.reverseOrder());
        System.out.println(list);

        // [3, 2, 1]
        list.sort((o1, o2) -> o2.compareTo(o1));
        System.out.println(list);

        // [3, 2, 1]
        list.sort(new Comparator<String>() {
            @Override
            public int compare(String o1, String o2) {
                return o2.compareTo(o1);
            }
        });
        System.out.println(list);

        // implements comparable
        List<Order> orders = new ArrayList<>();
        orders.add(new Order("4", 1));
        orders.add(new Order("3", 2));
        orders.add(new Order("2", 2));
        orders.add(new Order("1", 3));

        // [{"age: "1, "name:"4}, {"age: "2, "name:"2}, {"age: "2, "name:"3}, {"age: "3, "name:"1}]
        orders.sort(Order::compareTo);
        System.out.println(orders);

        // [{"age: "1, "name:"4}, {"age: "2, "name:"2}, {"age: "2, "name:"3}, {"age: "3, "name:"1}]
        orders.sort((o1, o2) -> o1.compareTo(o2));
        System.out.println(orders);

        // [{"age: "1, "name:"4}, {"age: "2, "name:"2}, {"age: "2, "name:"3}, {"age: "3, "name:"1}]
        Collections.sort(orders);
        System.out.println(orders);
    }


    @NoArgsConstructor
    @AllArgsConstructor
    public static class Order implements Comparable<Order> {
        private String name;
        private Integer age;

        @Override
        public int compareTo(Order o) {
            if (Objects.equals(this.age, o.age)) {
                return this.name.compareTo(o.name);
            }
            return this.age.compareTo(o.age);
        }

        @Override
        public String toString() {
            return "{\"age: \"" + this.age + ", \"name:\"" + this.name + "}";
        }
    }
}