【java】TreeSet的定制排序

package collection;import java.util.Comparator;import java.util.TreeSet;import org.junit.Test;/* * TreeSet的定制排序 */public class TestTreeSet02 {// 主方法public static void main(String[] args) {}@Test//测试方法一public void test1(){// 1，创建一个Comparator接口的实现类对象（匿名方式）Comparator com = new Comparator() {// 重写compare方法public int compare(Object o1, Object o2) {// 在compare方法中，传入自定义对象x，并指定是由x的哪一个具体属性做判断来排序//if(o1 instanceof Fruit && o2 instanceof Fruit)Fruit f1 = (Fruit) o1;Fruit f2 = (Fruit) o2;int result;result = f1.getNum() > f2.getNum() ? 1 : (f1.getNum() == f2.getNum() ? 0 : -1);if (result == 0) {result = f1.getKind().compareTo(f2.getKind());}return result;}};// 2，将上一步创建好的Comparable实现类对象com传入TreeSet()构造器TreeSet ts = new TreeSet(com);// 添加Comparable接口中compare方法中对应类型的对象ts.add(new Fruit(5, "Apple"));ts.add(new Fruit(6, "Banana"));ts.add(new Fruit(6, "Pear"));//ts.add(new Person(1001,"zhangsan",28));// 增强for循环遍历一下集合for (Object obj : ts) {System.out.println(obj);}}}// 自定义类Fruitclass Fruit {private int num;private String kind;public Fruit() {}public Fruit(int num, String kind) {this.num = num;this.kind = kind;}public int getNum() {return num;}public void setNum(int num) {this.num = num;}public String getKind() {return kind;}public void setKind(String kind) {this.kind = kind;}@Overridepublic String toString() {return "Fruit [num=" + num + ", kind=" + kind + "]";}@Overridepublic int hashCode() {final int prime = 31;int result = 1;result = prime * result + ((kind == null) ? 0 : kind.hashCode());result = prime * result + num;return result;}@Overridepublic boolean equals(Object obj) {if (this == obj)return true;if (obj == null)return false;if (getClass() != obj.getClass())return false;Fruit other = (Fruit) obj;if (kind == null) {if (other.kind != null)return false;} else if (!kind.equals(other.kind))return false;if (num != other.num)return false;return true;}}