treeSet实现排序两种放方法
//存入TreeSet集合中的元素是无序的，但有方法给它排序
//排序方式一：让元素自身具备比较性，需元素实现Comparable接口
//核心：重写Comparable接口的方法compareTo(Object obj)
//if (tea.age == this.age) //年纪相同时再按照姓名排序！！！
// return this.name.compareTo(tea.name);
//因为String也类实现了此接口，当然就可以调用compareTo()方法
class Teacher implements Comparable {
private int age;
private String name;
public Teacher(intage, String name) {
this.age = age;
this.name = name;
}
public int getAge() {
returnage;
}
public String getName() {
return name;
}
@Override
public String toString() {
return"Teacher [age="+ age +", name="+ name +"]";
}
@Override
public int compareTo(Object obj) {//按照年纪排序
Teacher tea = (Teacher) obj;
if(tea.age
return-1;
}
if(tea.age ==this.age) {//年纪相同时再按照姓名排序！！！核心
return this.name.compareTo(tea.name);
}
if(tea.age >this.age) {
return1;
}
return0;
}
}
publicclassTreeSetTest1 {
public static voidmain(String[] args) {
Teacher teac1=newTeacher(25,"lim");
Teacher teac2=newTeacher(26,"uim");
Teacher teac3=newTeacher(55,"zim");
Teacher teac4=newTeacher(55,"mim");
Teacher teac5=newTeacher(55,"cim");
TreeSet treeSet=newTreeSet();
treeSet.add(teac1);
treeSet.add(teac2);
treeSet.add(teac3);
treeSet.add(teac4);
treeSet.add(teac5);
Iterator iterator=treeSet.iterator();
while(iterator.hasNext()){
Teacher t=(Teacher) iterator.next();
System.out.println(t.getName()+"的年纪是"+t.getAge());
}
}
}
