Method reference instance method reference

The only difference between it and static method reference : Use the instance method called by the object .

package demo01;

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

import java.util.function.Supplier;

/**
 * @program: jdk8-02
 * @description:
 * @author:  Amur 
 * @create: 2022-02-15 08:46
 **/
public class Test01 {
    public static void main(String[] args) {
        Student s=new Student(" Zhang San ",18);
        // Use supplied function interface T get();
        Supplier<String> supplier=()->s.getName();
        System.out.println(supplier.get());
        //(args)-> Object name . Example method (args); ---  object :: Example method 
        Supplier<String> supplier1=s::getName;
        System.out.println(supplier1.get());

    }
}
@Data
@NoArgsConstructor
@AllArgsConstructor
class Student{
    private String name;
    private Integer age;
}

Object method reference

if Lambda The first parameter in the parameter list is the parameter caller of the instance method , And the second argument is the argument to the instance method , You can use object methods to reference .

package demo02;

import java.util.function.BiPredicate;

/**
 * @program: jdk8-02
 * @description:
 * @author:  Amur 
 * @create: 2022-02-15 08:52
 **/
public class Test02 {
    public static void main(String[] args) {
        BiPredicate<String,String> predicate=(t1,t2)->t1.equals(t2);
        System.out.println(predicate.test("hello", "Hello"));

        //(arg1,arg2)-->agr1. Example method (arg2);-----  Class name :: Example method .
        BiPredicate<String,String> predicate1=String::equals;
        System.out.println(predicate1.test("hello","hello"));
    }


}

Construction method reference

Be careful ： The argument list of the constructor to be invoked is consistent with the argument list of the abstract method in the functional interface .

package demo03;

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

import java.util.function.BiFunction;
import java.util.function.Supplier;

/**
 * @program: jdk8-02
 * @description:
 * @author:  Amur 
 * @create: 2022-02-15 09:04
 **/
public class Test03 {
    public static void main(String[] args) {
        Supplier<Student> supplier=()->new Student();
        System.out.println(supplier.get());

        // Conform to construction method reference 
        Supplier<Student> supplier1=Student::new;
        System.out.println(supplier1.get());

        BiFunction<String,Integer,Student> function=( t, u)->new Student(t,u);
        System.out.println(function.apply(" Zhang San ",20));

        BiFunction<String,Integer,Student> function1=Student::new;
        System.out.println(function1.apply(" Li Si ",19));


    }
}
@Data
@NoArgsConstructor
@AllArgsConstructor
class Student{
    private String name;
    private Integer age;
}