java8 方法引用

leokim / / JAVA

https://www.cnblogs.com/xiaoxi/p/7099667.html

/src/method_reference/Person.java

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package method_reference;
 
import java.time.LocalDate;
 
public class Person {
    public Person(String name, LocalDate birthday){
        this.name = name;
        this.birthday = birthday;
    }
 
    String name;
    LocalDate birthday;
 
    public LocalDate getBirthday(){
        return birthday;
    }
 
    public static int compareByAge(Person a, Person b){
        return a.birthday.compareTo(b.birthday);
    }
 
    @Override
    public String toString(){
        return this.name;
    }
 
}

/src/method_reference/testMethodReference.java

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package method_reference;
 
import java.time.LocalDate;
import java.util.Arrays;
import java.util.Comparator;
import org.junit.Test;
import method_reference.Person;
 
public class testMethodReference {
 
    @Test
    public void test(){
        Person[] pArr = new Person[]{
                new Person("003", LocalDate.of(2016,9,1)),
                new Person("001", LocalDate.of(2016,2,1)),
                new Person("002", LocalDate.of(2016,3,1)),
                new Person("004", LocalDate.of(2016,12,1))
        };
 
//        //使用匿名类
//        Arrays.sort(pArr, new Comparator<Person>() {
//            @Override
//            public int compare(Person o1, Person o2) {
//                return o1.getBirthday().compareTo(o2.getBirthday());
//            }
//        });
 
//        //使用lambda表达式 未调用已存在的方法
//        Arrays.sort(pArr, (Person o1, Person o2) -> {
//            return o1.getBirthday().compareTo(o2.getBirthday());
//        });
 
        //使用方法引用，引用的是类的静态方法
        Arrays.sort(pArr, Person::compareByAge);
 
        System.out.println(Arrays.asList(pArr));
    }
}