【Java学习笔记】<集合框架>TreeSet，Comparable，Comparator

 public class Person implements Comparable{
     private String name;
     private int age;

     public Person(){
         super();
     }
     public Person(String name, int age)
     {
         super();
         this.name = name;
         this.age = age;
     }

     @Override
     public int hashCode() {

         return name.hashCode()+age*27;
     }
     @Override
     public boolean equals(Object obj) {
         if (this == obj)
             return true;
         if (!(obj instanceof Person))
             throw new ClassCastException("类型错误");

         Person p = (Person) obj;

         return this.name.equals(p.name) && this.age ==  p.age;
     }
     @Override
     public String toString() {

         return name+":"+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 int compareTo(Object o) {    //先按年龄排，再按姓名排

         Person p = (Person)o;

         int temp = this.age - p.age;

         return temp==0? this.name.compareTo(p.name):temp;

     }

 }

 import java.util.Comparator;

 import cn.itcast.p1.bean.Person;

 public class ComparatorByName implements Comparator {    //先按姓名排，再按年龄排

     @Override
     public int compare(Object o1, Object o2) {
         Person p1 = (Person)o1;
         Person p2 = (Person)o2;

         int temp = p1.getName().compareTo(p2.getName());

         return temp==0?p1.getAge()-p2.getAge() : temp;
     }

 }

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

 import cn.itcast.p1.bean.Person;
 import cn.itcast.p5.comparator.ComparatorByName;

 public class TreeSetDemo {

     public static void main(String[] args) {
 //        demo1();
         TreeSet ts = new TreeSet(new ComparatorByName()); //添加  new ComparatorByName（），会出现结果一，去除的话 ，出现结果2
                                                             //Comparator 优先于  Comparable

         ts.add(new Person("zhangsan",28));
         ts.add(new Person("lisi",21));
         ts.add(new Person("zhouqi",29));
         ts.add(new Person("zhaoliu",25));
         ts.add(new Person("wangwu",24));
         ts.add(new Person("lisi",21));
         ts.add(new Person("zhouqi",29));

         Iterator it = ts.iterator();

         while (it.hasNext())
         {
             Person p = (Person)it.next();

             System.out.println(p);
         }

     }

     public static void demo1() {
         TreeSet ts = new TreeSet();

         ts.add("abc");
         ts.add("zaa");
         ts.add("aa");
         ts.add("nba");
         ts.add("cba");

         Iterator it = ts.iterator();

         while (it.hasNext())
         {
             System.out.println(it.next());
         }
     }

 }