Java_基础—TreeMap集合键是Student值是String的案例

秒速五厘米 2022-06-12 06:58 106阅读 0赞

**Student类，属性为name,age**  
实现接口Comparable，重写comparTo()方法，通过年龄的大小进行排序实现

public class Student implements Comparable<Student>{
        
            @Override
            public int compareTo(Student o) {
                int num = this.age - o.age;
                return num == 0 ? this.name.compareTo(o.name) : num;
            }       
    
    }

**TreeMap类**

package com.soar.map;
    
    import java.util.Comparator;
    import java.util.TreeMap;
    
    import com.soar.bean.Student;
    
    public class Demo7_TreeMap {
        
        /*
         * * A:案例演示
         * TreeMap集合键是Student值是String的案例
         */
        public static void main(String[] args) {
            //comparator();
            TreeMap<Student,String> tm = new TreeMap<>(new Comparator<Student>(){
    
                @Override
                public int compare(Student s1, Student s2) {
                    int num = s1.getName().compareTo(s2.getName());     //按照姓名的Unicode码比较
                    return num == 0 ? s1.getAge() - s2.getAge() : num;
                }   
            });
    
            tm.put(new Student("张三",23),"北京");
            tm.put(new Student("李四",24),"上海");
            tm.put(new Student("王五",25),"广州");
            tm.put(new Student("赵六",26),"深圳");
    
            System.out.println(tm);         //在Student对象类中重写comparTo方法，按照年龄的大小比较进行排序
    
        }
    
        private static void comparator() {
            TreeMap<Student,String> tm = new TreeMap<>();
            tm.put(new Student("张三",23),"北京");
            tm.put(new Student("李四",24),"上海");
            tm.put(new Student("王五",25),"广州");
            tm.put(new Student("赵六",26),"深圳");
    
            System.out.println(tm);
        }
    
    }