Comparable

一个比较器，为了做排序对象所用，一个通用的例子

 

 

public interface Order {
	public long getOrderIndex() ;
}

 

 

import java.util.Comparator;

/**
 * 升序排序
 *
 */
public class OrderAscStorComparator implements Comparator<Order> {

	@Override
	public int compare(Order o1, Order o2) {
		if (o1.getOrderIndex() > o2.getOrderIndex()){
			return 1;
		}else if(o1.getOrderIndex() < o2.getOrderIndex()){
			return -1;
		}else{
			return 0;
		}
	}

}

import java.util.Comparator;

/**
 * 降序排序
 *
 */
public class OrderDescStorComparator implements Comparator<Order> {

	@Override
	public int compare(Order o1, Order o2) {
		if(o1.getOrderIndex() > o2.getOrderIndex()){
			return -1;
		}else if(o1.getOrderIndex() < o2.getOrderIndex()){
			return 1;
		}else{
			return 0;
		}
	}
}

 当需要排序的时候，实现order这个接口，并实现相应的接口方法即可实现排序规则 

 

package com.vipshop.gmj.server.access.util;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.apache.commons.lang.math.RandomUtils;

import com.vipshop.gmj.server.framework.util.Order;
import com.vipshop.gmj.server.framework.util.OrderDescStorComparator;
/**
 * 排序测试
 * @author Administrator
 *
 */
public class OrderTest {
	public static void main(String[] args) {
		List<TestBean> beanList = new ArrayList<TestBean>();
		for(int i=0;i<10;i++){
			TestBean bean = new TestBean();
			bean.setIdlong(RandomUtils.nextLong());
			beanList.add(bean);
		}
		
		Collections.sort(beanList,new OrderDescStorComparator());
		
		for(int i=0;i<beanList.size() ;i++){
			TestBean bean = beanList.get(i);
			System.out.println(bean.getIdlong());
		}
	}
	
}
class TestBean implements Order{
	private long idlong;
	
	public long getIdlong() {
		return idlong;
	}

	public void setIdlong(long idlong) {
		this.idlong = idlong;
	}

	@Override
	public long getOrderIndex() {
		return this.idlong;
	}
	
}