TreeSet多字段排序

package st;

public class PersonBean implements Comparable<Object>{

    private String name;    
    private int age;    
    
    PersonBean(String name, int age) {    
        this.name = name;    
        this.age = age;    
    }    
    
    public String getName() {    
        return name;    
    }    
    
    public int getAge() {    
        return age;    
    }    
    
    @Override    
    public int compareTo(Object obj) {    
        if (!(obj instanceof PersonBean))    
            throw new RuntimeException();    
        /**  
         * 在这里定义比较对象大小的方法  
         * 先进行年龄的比较，年龄不相等再进行姓名的比较  
         * 如果年龄与姓名都相等，那么就代表同一个对象  
         */    
        PersonBean pe = (PersonBean) obj;    
        if (this.age > pe.age)    
            return 1;    
        if (this.age == pe.age) {    
            return this.name.compareTo(pe.name);    
        }    
    
        return -1;    
    }    

}

import java.util.Iterator;
import java.util.TreeSet;

public class Dup {
        public static void main(String[] args) {    
        
            // 向这个集合中存储自定义对象    
            TreeSet<PersonBean> ts = new TreeSet<PersonBean>();    
            ts.add(new PersonBean("lishi", 22));    
            ts.add(new PersonBean("lishi1", 23));    
            ts.add(new PersonBean("lishi56", 25));    
            ts.add(new PersonBean("lishi4", 25));    
        
            //获取迭代器，取出其中的元素    
            Iterator<PersonBean> it = ts.iterator();    
            while (it.hasNext()) {    
                PersonBean pe = (PersonBean) it.next();    
                System.out.println(pe.getAge() + "  " + pe.getName());    
            }    

}
}