Java容器---Comparator接口和Comparable接口

/**
 * created by yangyinglong at 20180517
 * 排序方式的学习
 * Comparator 和 Comparable 两个接口的学习
 */

import java.util.*;

public class ComparatorTest {
	public static void main(String[] argv) {
		List<Person> personList = new ArrayList<Person>();
		personList.add(new Person(11, "xiaoming", 1));
		personList.add(new Person(12, "xiaoming", 1));
		personList.add(new Person(12, "xiaoming", 0));
		personList.add(new Person(12, "xiaohong", 1));
		personList.add(new Person(13, "xiaohong", 0));

		personList.add(new Person(11, "xiaoming", 0));
		personList.add(new Person(13, "xiaoming", 1));

		//对personList随机排列
		Collections.shuffle(personList);
		Iterator<Person> iterator_1 = personList.iterator();
		System.out.println("随机排序之后的结果");
		System.out.println("  NAME  \tAGE\tSEX");
		while (iterator_1.hasNext()) {
			Person per = iterator_1.next();
			System.out.println(per);
		}
		// 随机排序之后的结果
		//   NAME  	AGE	SEX
		// xiaoming	11	0
		// xiaoming	11	1
		// xiaoming	13	1
		// xiaoming	12	1
		// xiaohong	13	0
		// xiaohong	12	1
		// xiaoming	12	0

		//对personList用PerComparator类进行排序
		Collections.sort(personList, new PerComparator());
		System.out.println("用PerComparator排序之后的结果");
		Iterator<Person> iterPer_2 = personList.iterator();
		while (iterPer_2.hasNext()) {
			Person per = iterPer_2.next();
			System.out.println(per);
		}
		// 用PerComparator排序之后的结果
		// xiaohong	12	1
		// xiaohong	13	0
		// xiaoming	11	0
		// xiaoming	11	1
		// xiaoming	12	0
		// xiaoming	12	1
		// xiaoming	13	1


		// // test2
		// ArrayList<Student> arrayList = new ArrayList<Student>();
		// arrayList.add(new Student("zhangsan",89.8));
		// arrayList.add(new Student("lisi",90));
		// arrayList.add(new Student("wangwu",60.6));
		// arrayList.add(new Student("wangting",85.6));

		// Iterator<Student> iterator_stu = arrayList.iterator();
		// while (iterator_stu.hasNext()) {
		// 	Student stu_one = iterator_stu.next();
		// 	System.out.println(stu_one);
		// }
		// // zhangsan	89.8
		// // lisi	90.0
		// // wangwu	60.6
		// // wangting	85.6

		// // System.out.println(arrayList);
		
		// // ×××××××××排序×××××××××××
		// Collections.sort(arrayList);
		// // for (Student stu: arrayList) {
		// // 	System.out.println(stu);
		// // }
		// Iterator<Student> iterator_stu_1 = arrayList.iterator();
		// while (iterator_stu_1.hasNext()) {
		// 	Student stu_one = iterator_stu_1.next();
		// 	System.out.println(stu_one);
		// }
		// // lisi	90.0
		// // zhangsan	89.8
		// // wangting	85.6
		// // wangwu	60.6


		

	}
}


class Person {
	private int age;
	private String name;
	//1代表男，0代表女
	private int sex;

	public Person(int age, String name, int sex) {
		this.age = age;
		this.name = name;
		this.sex = sex;
	}

	public int getAge() {
		return this.age;
	}

	public String getName() {
		return this.name;
	}

	public int getSex() {
		return this.sex;
	}

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

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

	public void setSex(int sex) {
		this.sex = sex;
	}

	public String toString() {
		return this.name + "\t" + this.age + "\t" + this.sex;
	}
}

class PerComparator implements Comparator<Person> {

	@Override
	public int compare(Person person1, Person person2) {
		int cr = 0;
		//按姓名升序排序
		int a = person1.getName().compareTo(person2.getName());
		if (a != 0) {
			cr = (a > 0) ? 3 : -1;
		} else {
			//按年龄升序排序
			a = person1.getAge() - person2.getAge();
			if (a != 0) {
				cr = (a > 0) ? 2 : -2;
			} else {
				a = person1.getSex() - person2.getSex();
				if (a != 0) {
					cr = (a > 0) ? 1 : -3;
				}
			}
		}
		return cr;
	}
}

// Comparable接口中的compareTo()方法:
// 凡是需要进行比较排序的类都应该实现Comparable接口中的compareTo()方法；
// 凡是把类对象放到以树为内部结构的容器中都应该实现Comparable接口中的compareTo()方法 test3


// 1、凡是把类对象放到容器中，相应的类都应该实现Object类中的toString()方法； 
// 2、凡是需要进行比较排序的类都应该实现Comparable接口中的compareTo()方法；
// 凡是把类对象放到以树为内部结构的容器中都应该实现Comparable接口中的compareTo()方法 
// 3、凡是把类对象放到以哈希表为内部存储结构的容器中，相应的类必须要实现equals方法和hashCode方法，
// 这样才符合哈希表真实的逻辑功能. 
// 4、逻辑上来讲，只要两个对象的内容相同，其地址(hashCode()返回值)以及这两个对象就应该相同(equals())。

public class Student implements Comparable<Object> {
	private String name;
	private double score;

	public Student(String name, double score) {
		this.name = name;
		this.score = score;
	}

	public String getName() {
		return this.name;
	}

	public double getScore() {
		return this.score;
	}

	public String toString() {
		return this.name + "\t" + this.score;
	}

	@Override
	public int compareTo(Object s)  {
		Student stu = (Student)s;
		if(stu.getScore() > this.score) {
			return 1;
		} else if (stu.getScore() < this.score) {
			return -1;
		} else {
			return 0;
		}
	}

	public boolean equals(Object obj) {
		if (obj instanceof Student) {
			Student stu = (Student)obj;
			return this.getName().equals(stu.getName());
		}
		return super.equals(obj);
	}

	public int hashCode() {
		return (int)(this.getName().hashCode()*this.getScore());
	}
}