对象数组排序

对象数组的排序需要类实现Compareable接口。
Compareable接口中的compareTo方法返回一个整型数值，用来表示两个对象的大小或相等状态。

public class Person implements Comparable<Person> {
	private String id;
	private String name;

	@Override
	public String toString() {
		return "ID:" + id + "  NAME:" + name;
	}

	public int compareTo(Person o) {
		int compareId = this.id.compareToIgnoreCase(o.id);
		if (0 != compareId)
			return compareId;
		int compareName = this.name.compareToIgnoreCase(o.name);
		if (0 != compareName)
			return compareName;
		return 0;
	}
	public String getId() {
		return id;
	}

	public void setId(String id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

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

public static void main(String[] args) {
		Person[] p = new Person[3];
		p[0] = new Person();
		p[0].setId("bbb");
		p[0].setName("222");
		p[1] = new Person();
		p[1].setId("ccc");
		p[1].setName("111");
		p[2] = new Person();
		p[2].setId("aaa");
		p[2].setName("222");

		Arrays.sort(p);

		for (Person pe : p) {
			System.out.println(pe);
		}

	}

运行结果：
ID:aaa  NAME:222
ID:bbb  NAME:111
ID:bbb  NAME:222