标签：return int MyDate 课后 Employee new 习题 public TreeSet
TreeSet课后习题
package com.atguigu.exer1;
import org.junit.Test;
import java.util.Comparator;
import java.util.Iterator;
import java.util.TreeSet;
/**
* 创建该类的5个对象，并把这些对象放入TreeSet集合中，分别按一下两种方式对集合中的元素进行排序。并遍历输出
* <p>
* 1.使Employee实现Comparable接口，并按name排序
* 2.创建TreeSet时传入Comparator对象，按生日日期的先后排序
*
* @author liangqichen
* @create 2021-09-28 21:27
*/
public class EmployeeTest {
// 问题2 按生日日期的先后顺序
@Test
public void test2() {
TreeSet set = new TreeSet(new Comparator() {
@Override
public int compare(Object o1, Object o2) {
if(o1 instanceof Employee && o2 instanceof Employee) {
Employee e1 = (Employee) o1;
Employee e2 = (Employee) o2;
MyDate b1 = e1.getBirthday();
MyDate b2 = e2.getBirthday();
// 方式 一
// // 比较年
// int minusYear = b1.getYear() - b2.getYear();
// if(minusYear != 0){
// return minusYear;
// }
//
// // 比较月
// int minMonth = b1.getMonth() - b2.getMonth();
// if(minMonth != 0){
// return minMonth;
// }
//
// // 比较日
// return b1.getDay() - b2.getDay();
// }
// 方式 二 ：
return b1.compareTo(b2);
}
return 0;
}
});
Employee e1 = new Employee("liudehua", 55, new MyDate(1965, 5, 4));
Employee e2 = new Employee("zhangxueyou", 43, new MyDate(1987, 5, 4));
Employee e3 = new Employee("guofucheng", 44, new MyDate(1987, 5, 9));
Employee e4 = new Employee("liming", 51, new MyDate(1954, 8, 12));
Employee e5 = new Employee("liangchaowei", 21, new MyDate(1958, 12, 4));
set.add(e1);
set.add(e2);
set.add(e3);
set.add(e4);
set.add(e5);
Iterator iterator = set.iterator();
while (iterator.hasNext()) {
System.out.println(iterator.next());
}
}
// 问题1 使用自然排序
@Test
public void test1() {
TreeSet set = new TreeSet();
Employee e1 = new Employee("liudehua", 55, new MyDate(1965, 5, 4));
Employee e2 = new Employee("zhangxueyou", 43, new MyDate(1987, 5, 4));
Employee e3 = new Employee("guofucheng", 44, new MyDate(1987, 5, 9));
Employee e4 = new Employee("liming", 51, new MyDate(1954, 8, 12));
Employee e5 = new Employee("liangchaowei", 21, new MyDate(1958, 12, 4));
set.add(e1);
set.add(e2);
set.add(e3);
set.add(e4);
set.add(e5);
Iterator iterator = set.iterator();
while (iterator.hasNext()) {
System.out.println(iterator.next());
}
}
}
package com.atguigu.exer1;
/**
* 定义一个Employee类。
* 该类包含：private成员变量name，age，birthday，其中birthday 为MayDate类的对象：
* 并为每一个属性定义getter setter方法
* 并重写toString方法输出name age birthday
*
* @author liangqichen
* @create 2021-09-28 21:23
*/
public class Employee implements Comparable{
private String name;
private int age;
private MyDate birthday;
public Employee() {
}
public Employee(String name, int age, MyDate birthday) {
this.name = name;
this.age = age;
this.birthday = birthday;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public MyDate getBirthday() {
return birthday;
}
public void setBirthday(MyDate birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
return "Employee{" +
"name='" + name + '\'' +
", age=" + age +
", birthday=" + birthday +
'}';
}
// 按照 name 的顺序排
@Override
public int compareTo(Object o) {
if(o instanceof Employee){
Employee e = (Employee) o;
return this.name.compareTo(e.name);
}
// return 0;
throw new RuntimeException("传入的数据类型不一致！");
}
}
package com.atguigu.exer1;
/**
* MyDate类包含：
* private成员变量year，month，day。并为每一个属性定义getter setter 方法。
*
* @author liangqichen
* @create 2021-09-28 21:20
*/
public class MyDate implements Comparable{
private int year;
private int month;
private int day;
public MyDate() {
}
public MyDate(int year, int month, int day) {
this.year = year;
this.month = month;
this.day = day;
}
public int getYear() {
return year;
}
public void setYear(int year) {
this.year = year;
}
public int getMonth() {
return month;
}
public void setMonth(int month) {
this.month = month;
}
public int getDay() {
return day;
}
public void setDay(int day) {
this.day = day;
}
@Override
public String toString() {
return "MyDate{" +
"year=" + year +
", month=" + month +
", day=" + day +
'}';
}
@Override
public int compareTo(Object o) {
if (o instanceof MyDate) {
MyDate m = (MyDate) o;
// 比较年
int minusYear = this.getYear() - m.getYear();
if (minusYear != 0) {
return minusYear;
}
// 比较月
int minMonth = this.getMonth() - m.getMonth();
if (minMonth != 0) {
return minMonth;
}
// 比较日
return this.getDay() - m.getDay();
}
throw new RuntimeException("传入的数据类型不一致！！");
}
}
标签：return,int,MyDate,课后,Employee,new,习题,public,TreeSet 来源： https://blog.csdn.net/weixin_56711112/article/details/120539345
本站声明： 1. iCode9 技术分享网（下文简称本站）提供的所有内容，仅供技术学习、探讨和分享； 2. 关于本站的所有留言、评论、转载及引用，纯属内容发起人的个人观点，与本站观点和立场无关； 3. 关于本站的所有言论和文字，纯属内容发起人的个人观点，与本站观点和立场无关； 4. 本站文章均是网友提供，不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属；如您发现该文章侵犯了您的权益，可联系我们第一时间进行删除； 5. 本站为非盈利性的个人网站，所有内容不会用来进行牟利，也不会利用任何形式的广告来间接获益，纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。