java 复习笔记57

第二种排序方式：定制排序
public void test(){
1.创建一个实现了Comparator 接口的对象
Comparator com = new Comparator(){
在compare 方法中指明是用自定义类的哪个属性进行排序的
public int compare(Object o1,Object o2){
if(o1 instanceof Customer && o2 instanceof Customer){
Customer c1 = (Customer)o1;
Customer c2 = (Customer)o2;
int i = c1.name.compareTo(c2.name);
if(i == 0){
return c1.age.compareTo(c2.age);
}else
return i;
}
return 0;
}
};
2.将定制的排序指定给TreeSet对象
TreeSet t = new TreeSet(com);
3.向TreeSet 中添加compare 中指定的类的对象
t.add(new Customer("qinjianbo",12));
t.add(new Customer("wanghui",11));
}
public void test1(){
还可以直接这样
TreeSet t = new TreeSet(new Comparetor{
在compare 方法中指明是用自定义类的哪个属性进行排序的
public int compare(Object o1,Object o2){
if(o1 instanceof Customer && o2 instanceof Customer){
Customer c1 = (Customer)o1;
Customer c2 = (Customer)o2;
int i = c1.name.compareTo(c2.name);
if(i == 0){
return c1.age.compareTo(c2.age);
}else
return i;
}
return 0;
}
});
t.add(new Customer("qinjianbo",12));
t.add(new Customer("wanghui",11));
}