TreeMap集合键是Student值是String的案例

TreeMap集合键是Student值是String的案例

• A：案例演示
  • TreeMap集合键是Student值是String的案例

package com.heima.bean;

public class Student implements Comparable<Student>{
	private String name;
	private int age;

	public Student() {
		super();
	}

	public Student(String name, int age) {
		super();
		this.name = name;
		this.age = age;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	@Override
	public String toString() {
		return "Student [name=" + name + ", age=" + age + "]";
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + age;
		result = prime * result + ((name == null) ? 0 : name.hashCode());
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Student other = (Student) obj;
		if (age != other.age)
			return false;
		if (name == null) {
			if (other.name != null)
				return false;
		} else if (!name.equals(other.name))
			return false;
		return true;
	}

	@Override
	public int compareTo(Student o) {
		int num = this.age - o.age;					//以年龄为主要条件
		return num == 0 ? this.name.compareTo(o.name) : num;
	}
}


package com.itheima.map;

import java.util.Comparator;
import java.util.TreeMap;

import com.heima.bean.Student;

public class Demo07_TreeMap {

	public static void main(String[] args) {
		//demo1();
		TreeMap<Student, String> tm = new TreeMap<>(new Comparator<Student>() {

			@Override
			public int compare(Student s1, Student s2) {
				int num = s1.getName().compareTo(s2.getName());		//按照姓名比较
				return num == 0 ? s1.getAge() - s2.getAge() : num;
			}
		});
		tm.put(new Student("张三", 23), "北京");
		tm.put(new Student("李四", 13), "上海");
		tm.put(new Student("赵六", 43), "深圳");
		tm.put(new Student("王五", 33), "广州");
		
		System.out.println(tm);
	}

	public static void demo1() {
		TreeMap<Student, String> tm = new TreeMap<>();
		tm.put(new Student("张三", 23), "北京");
		tm.put(new Student("李四", 13), "上海");
		tm.put(new Student("王五", 33), "广州");
		tm.put(new Student("赵六", 43), "深圳");
		
		System.out.println(tm);
	}
}