JAVA中用Set集合的TreeSet类对姓名和编号排序

在Per类中以内部类形式实现比较器PerComparator,在写比较器前要实现compareTo方法,谁能告诉我?

答案：按编号的排序,compareTo比较一下就可以了:
 
import java.util.Iterator;
import java.util.TreeSet;
public class PriorityTest extends TreeSet<PriorityTest.Test>{
 static class Test implements Comparable<Test>{
  String name;
  int num;
  
  public Test(String name, int num) {
   this.name = name;
   this.num = num;
  }
  
  public int compareTo(Test arg) { 
   if(num < arg.num)
    return 1;
   else if(num > arg.num)
    return -1;
   else 
    return 0;
  } 
  
  public String toString(){
   return name;//Character.toString(arg0)
  }
 }
 
 public void add(String str, int priority){
  super.add(new Test(str,priority));
 }
 
 public static void main(String args[]){
  PriorityTest pTest = new PriorityTest();
  pTest.add("小明1",1);
  pTest.add("小红3",3);
  pTest.add("小张2",2);
  
  
  
  for(Iterator iter = pTest.iterator();iter.hasNext();){
   Object obj = iter.next();
   System.out.println(obj);
  }
 }
}
 
定义内部类. 至于里面怎么比较,就看具体的情况了,这里只随便比较一下name
public class Per{
    private String name;
    private class PerComparator implements Comparator
           public int compareTo(Object obj1, Object obj2){
                   return ((Per)obj1.getName().hashCode()-(Per).getName().hashCode());       
           }
 
   public String getName(){
             return name;
    }
}

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