Compareble 接口與Comparator接口比較

Compareble接口

     可以直接通過Arrays.sort 對數組進行排序

import java.util.Arrays;

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

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

	@Override
	public int compareTo(Student o) {
		// TODO Auto-generated method stub
		if (this.age < o.age) {
			return -1;
		}
		if (this.age > o.age) {
			return 1;
		} else {
			if (this.score < o.score) {
				return -1;
			}
			if (this.score > o.score) {
				return 1;
			}

		}

		return 0;
	}
      public static void main(String[] args) {
		Student  stu[]={
				new Student("馬超", 68, 88),
				new Student("趙雲", 30, 90),
				new Student("關二個", 33, 99),
				new Student("張飛",32, 92)
		};
		Arrays.sort(stu);
		for (int i = 0; i < stu.length; i++) {
			System.out.println(stu[i]);
		}
	}
}

輸入結果 Student [name=趙雲, age=30, score=90]
Student [name=張飛, age=32, score=92]
Student [name=關二個, age=33, score=99]
Student [name=馬超, age=68, score=88]
如果 Student類沒有實現comparable 則會拋出Student cannot be cast to java.lang.Comparable （student類不能被拋到java.lang.Comparable ）說明arrays.sort()實現是根據compareble進行數組排序的。引用一老兄的話：java中的對象排序永遠都是以Comparable 接口爲標準的。、

另一種比較器 comparator  

comparator接口中實現的方法

compare（T o1,To2）---比較用來比較的2個參數

compare 主要作用是用來對已經寫好的類，但是沒有實現comparable 接口進行的補充。

http://blog.csdn.net/cz1029648683/article/details/6666855  一位老兄的文章。