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());
}
}
}
