java123-treeset排序集合

import java.util.Comparator;

public class GoodsSorts implements Comparator {
public int compare(Object o1,Object o2){
Goods g1=(Goods)o1;
Goods g2=(Goods)o2;
System.out.println("调用排序方法");
if(g1.getPrice()>g2.getPrice()){
return -1;
}else if(g1.getPrice()<g2.getPrice()){
return 1;
}
return 0;
}
}
测试类import java.util.TreeSet;

public class test63 {
public static void main(String[] args){
TreeSet tree=new TreeSet(new GoodsSorts());//创建一个采用默认树形自然排序的对象
Goods g0=new Goods();
g0.setName("剃须刀");
g0.setPrice(2000.0);
Goods g1=new Goods();
g1.setName("西瓜");
g1.setPrice(7000.0);
Goods g2=new Goods();
g2.setName("小刀");
g2.setPrice(3000.0);
Goods g3=new Goods();
g3.setName("矿泉水");
g3.setPrice(4000.0);
tree.add(g3);
tree.add(g2);
tree.add(g1);
tree.add(g0);
for(Object o:tree){
System.out.println(((Goods)o).getName()+"\t"+((Goods)o).getPrice());
}
System.out.println("第一个"+((Goods)tree.first()).getName());
System.out.println("最后一个"+((Goods)tree.last()).getName());
}
}

运行结果