方法一
此方法需要传入一个实现了Comparable接口的对象类的集合
创建实现了Comparable的对象类
public class Student1 implements Comparable<Student1> {
private String name;
private int age;
public Student1() {
}
public Student1(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public int compareTo(Student1 s) {
int num = this.age - s.age;
int num1 = (num == 0 ? this.name.compareTo(s.name) : num);
return num1;
}
}
调用
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class Student1Test {
public static void main(String[] args) {
List<Student1> list1 = new ArrayList<Student1>();
list1.add(new Student1("林青霞", 27));
list1.add(new Student1("风清扬", 30));
list1.add(new Student1("刘晓曲", 28));
list1.add(new Student1("武鑫", 29));
list1.add(new Student1("林青霞", 27));
Student1 min=Collections.min(list1);
System.out.println(min.getName()+"---"+min.getAge());
Student1 max=Collections.max(list1);
System.out.println(max.getName()+"---"+max.getAge());
}
}
方法二
此方法传入一个对象类的集合,以及一个比较器
(根据比较器定义的规则来对对象类的集合做大小比较
)
创建对象类
public class Student2 {
private String name;
private int age;
public Student2() {
}
public Student2(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
调用
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
public class Student2Test {
public static void main(String[] args) {
List<Student2> list2 = new ArrayList<Student2>();
list2.add(new Student2("林青霞", 27));
list2.add(new Student2("风清扬", 30));
list2.add(new Student2("刘晓曲", 28));
list2.add(new Student2("武鑫", 29));
list2.add(new Student2("林青霞", 27));
Student2 min=Collections.min(list2,new MyComparator());
System.out.println(min.getName()+"---"+min.getAge());
Student2 max=Collections.max(list2,new MyComparator());
System.out.println(max.getName()+"---"+max.getAge());
}
}
class MyComparator implements Comparator<Student2> {
@Override
public int compare(Student2 s1, Student2 s2) {
int num = s1.getAge() - s2.getAge();
int num1 = (num == 0 ? s1.getName().compareTo(s2.getName()) : num);
return num1;
}
}
本文转载自:https://blog.csdn.net/lei2879223426/article/details/77430206