java 接口案例

这个是主程序

package demo;

import java.util.ArrayList;

public class SortUtil {
	
	public static void sort(ArrayList uList,BijiaoQi bijiaoQi) {
		for(int i=0;i

package demo;

public interface BijiaoQi {
	
	public boolean bijiao(User u1,User u2);

}

先实现比较器要求的接口

package demo;

public class AgeBijiaoqi implements BijiaoQi{

	@Override
	public boolean bijiao(User u1, User u2) {
		if(u1.getAge()>u2.getAge()) {
			return true;
		}
		return false;
	}

}

package cn.edu360.javase24.day08.sortutil1;

import java.util.ArrayList;


public class Test {
	public static void main(String[] args) {
		
		ArrayList uList = new ArrayList<>();
		User u1 = new User("1", "a", 18,2000);
		User u2 = new User("2", "b", 19,3000);
		User u3 = new User("3", "c", 28,1800);
		User u4 = new User("4", "d", 20,2300);
		uList.add(u1);
		uList.add(u2);
		uList.add(u3);
		uList.add(u4);
		
		// 专门新建一个比较器实现类，然后new出来传进去
		SortUtil.sort(uList, new AgeBijiaoqi());
		
		// 或者使用匿名内部类来传递具体的比较器对象
		SortUtil.sort(uList, new BijiaoQi() {
			
			@Override
			public boolean bijiao(User u1, User u2) {
				if(u1.getSalary() > u2.getSalary()) {
					return true;
				}
				return false;
			}
		});
		
	}

}