lamda代码演示

public class Person {
    private int id;
    private String name;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Person(){};
    public Person(int id,String name){
        this.id = id;
        this.name = name;
    }

}

import com.ruoyi.web.controller.demo.domain.Person;

import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;

public class Test01 {
    public static void main(String[] args) {
        List<Person> listd = new ArrayList<>();
        listd.add(new Person(2,"张三"));
        listd.add(new Person(22,"李四"));
        listd.add(new Person(12,"王五"));
        listd.add(new Person(23,"赵六"));
        listd.add(new Person(24,"寒气"));

        //常规写法
        /*listd.sort(new Comparator<Person>(){
            @Override
            public int compare(Person o1, Person o2) {
                return o1.getId() - o2.getId();
            }
        });*/

        //lamda写法
        listd.sort((l1,l2) -> {
            return l1.getId() - l2.getId();
        });

        for (int i = 0; i < listd.size(); i++) {
            System.out.println(listd.get(i).getId());
        }
    }
}

控制台结果： 

 

 

 演示2

写一个函数式接口

public interface Rfunct {
    void sayHello(String msg);
}

测试主类

public class Test02 {
    public static void main(String[] args) {
        Rfunct rf = message -> {
            System.out.println("Hello "+message);
        };
        rf.sayHello("lamda");
    }
}

控制台结果