【Java TreeMap】测试TreeMap的使用、Comparabe自定义类的自定义排序方式

TreeMap

TreeMap<键,值对>底层是红黑树，元素放进去之后会自动根据key排序。

测试代码

测试TreeMap的使用、Comparabe自定义类的自定义排序方式e

package cn.hanquan.test;import java.util.Map; import java.util.TreeMap;public class TreeMapTest {public static void main(String[] args) {Map<Employee, String> treemap1 = new TreeMap<>();treemap1.put(new Employee(5, "布小谷", 2000), "buxiaogu");treemap1.put(new Employee(2, "淳于乔", 5000), "chunyuqiao");treemap1.put(new Employee(1, "魔鬼鱼", 5000), "moguiyu");treemap1.put(new Employee(3, "雷军", 10000), "leijun");treemap1.put(new Employee(4, "雷奕明", 3000), "leiyiming");for (Employee key : treemap1.keySet()) {System.out.println(key.toString() + "->" + treemap1.get(key));}} }class Employee implements Comparable<Employee> {int id;String name;double salary;public Employee(int id, String name, double salary) {super();this.id = id;this.name = name;this.salary = salary;}@Overridepublic int compareTo(Employee o) {//自己的比较规则if (this.salary > o.salary) {return 1;} else if (this.salary < o.salary) {return -1;} else if (this.id > o.id) {return 1;} else if (this.id < o.id) {return -1;} elsereturn 0;}public String toString() {String str = new String(id + " " + name + " " + salary);return str;} }

输出

5 布小谷 2000.0->buxiaogu
4 雷奕明 3000.0->leiyiming
1 魔鬼鱼 5000.0->moguiyu
2 淳于乔 5000.0->chunyuqiao
3 雷军 10000.0->leijun

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