题目
定义学生对象,存储到集合中,按照姓名长度来存,长度相同比较名字大小,随后比较年龄
分析
使用 双链集合中的 TreeMap来存
注意:使用比较器来比较或者实现Comparable接口,重写compareTo这个方法
程序代码
//学生类
package com.company.test;
public class Student {
private String name;
private int age;
public Student() {
}
public Student(String name, int age) {
this.name = name;
this.age = age;
}
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;
}
@Override
public String toString() {
return "Student{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
}
package com.company.test;
import java.util.Comparator;
import java.util.Set;
import java.util.TreeMap;
public class MyTest {
public static void main(String[] args) {
TreeMap<Student, String> map = new TreeMap<>(new Comparator<Student>() {
@Override
public int compare(Student s1, Student s2) {
//按照姓名长度来排序
int num=s1.getName().length()-s2.getName().length();
int num2=num==0?s1.getName().compareTo(s2.getName()):num;
int num3=num2==0?s1.getAge()-s2.getAge():num2;
return num3;
}
});
map.put(new Student("貂蝉", 19), "001");
map.put(new Student("杨玉环", 23), "002");
map.put(new Student("赛西施", 24), "003");
map.put(new Student("王昭君", 30), "004");
map.put(new Student("李白", 24), "003");
map.put(new Student("韩信", 30), "004");
Set<Student> stu= map.keySet();
for (Student student : stu) {
System.out.println(student.getAge() + "===" + student.getName() + "========" + map.get(student));
}
}
}