java方法引用学习

package jdk18.method.reference;
public class Student {
    private String name;
    private int score;

    public Student(){

    }

    public Student(String name,int score){
        this.name = name;
        this.score = score;
    }

    public String getName() {
        return name;
    }

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

    public int getScore() {
        return score;
    }

    public void setScore(int score) {
        this.score = score;
    }

    public static int compareStudentByScore(Student student1,Student student2){
        return student1.getScore() - student2.getScore();
    }
    
    public int compare1(Student other){
    	return this.score - other.score; 
    }
    
    public int compare2(Student student1,Student student2){
    	return student1.getScore() - student2.getScore();
    }
    public void print(){
    	System.out.print(this);
    }

    public Integer aa(int i){
    	System.out.println(score+i);
    	return i;
    }
    
	@Override
	public String toString() {
		return "Student [name=" + name + ", score=" + score + "]";
	}
    
}

package jdk18.method.reference;

public class StudentComparator {
   
	public int compareStudentByScore(Student student1,Student student2){
		
        return student2.getScore() - student1.getScore();
    }
}

package jdk18.method.reference;

public interface TestInterface {

	public int t(Student t1, Student t2, Student t3);
}

测试类;

package jdk18.method.reference;

import java.util.Arrays;
import java.util.List;
import java.util.function.BiFunction;


public class TestMain {
  
	public static void main(String[] args) {
		f5();
		
	}
	static List<Student> students = null;
	static {
		Student student1 = new Student("zhangsan",60);
		Student student2 = new Student("lisi",70);
		Student student3 = new Student("wangwu",80);
		Student student4 = new Student("zhaoliu",90);
		students = Arrays.asList(student1,student2,student3,student4);
	}
	static void f1(){
		students.sort((o1, o2) -> o1.getScore() - o2.getScore());
		students.forEach(student -> System.out.println(student.getScore()));
	}
	
	static void f2(){
		students.sort(Student::compareStudentByScore);
		students.forEach(student -> System.out.println(student.getScore()));
	}
	
	static void f3(){
		StudentComparator studentComparator = new StudentComparator();
		students.sort(studentComparator::compareStudentByScore);
		students.forEach(student -> System.out.println(student.getScore()));
	}
	
	static void f4(){
		students.forEach(Student::print);
	}
	/**
	 * 实例方法引用总结：首先肯定是与函数式接口强相关，
	 * 类名：：方法名，其实感觉是this隐式的作为参数传入方法内，调用的时候直接用this调用这个方法，
	 * 所以，这种情况方法引用的参数要比函数式接口中的抽象方法少一个，即this占用了一个，而且是占用的第一个，
	 * 如果函数式接口的抽象方法有一个参数， 1.可以直接调用无参数方法（this表示该参数，引用的方法，即直接使用这个this来调用）
	 *             
	 * 如果函数式接口的抽象方法有两个参数   2.只能引用有一个参数的方法，且该参数类型必须是这个类的类型，相当于改函数式接口中的第二个参数，
	 *                          因为第一个参数还是被this占用着。
	 * 注：集合也会自动帮助顺序取多个元素与参数方法的多个参数相对应
	 */
	static void f5(){
		students.sort(Student::compare1);
		students.forEach(System.out::print);
		//students.forEach(Student::compare1);
		//students.sort(Student::compare2);
		//TestMain.filter(Student::compare2);
	}
	
	public static void hehe(BiFunction<Student, Integer, Integer>on){
		System.out.println(on.apply(students.get(0), 3));
		
	}
	
	public static void f6(){
		BiFunction<Student, Integer, Integer> on = Student::aa;
		hehe(on);
	}
	
	static void filter(TestInterface i){
		if(i.t(students.get(0), students.get(0), students.get(0)) == 0){
			System.out.println("oooooooooo");
		}
	}
}