有关Collection中sort排序

Collections中sort()方法如果比较的是对象

package com.huan.yu;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;



public class Demo {

	public static void main(String[] args) {
		List<CustomerOrder> customerOrders = new ArrayList();

		Map map = new HashMap();

		CustomerOrder customerOrder = new CustomerOrder((long) 1,"huanyu1", "xiaozhang", "xiaoli", 1);
		CustomerOrder customerOrder1 = new CustomerOrder((long) 2,"huanyu1", "xiaozhang", "xiaoli", 4);
		CustomerOrder customerOrder2 = new CustomerOrder((long) 3,"huanyu1", "xiaozhang", "xiaoli", 5);

		CustomerOrder customerOrder3 = new CustomerOrder((long) 4,"huanyu", "xiaozhang", "xiaoli", 6);
		CustomerOrder customerOrder4 = new CustomerOrder((long) 5,"huanyu", "xiaozhang", "xiaoli", 7);
		CustomerOrder customerOrder5 = new CustomerOrder((long) 6,"huanyu2", "xiaozhang", "xiaoli", 9);
		customerOrders.add(customerOrder);
		customerOrders.add(customerOrder1);
		customerOrders.add(customerOrder2);
		customerOrders.add(customerOrder3);
		customerOrders.add(customerOrder4);
		customerOrders.add(customerOrder5);
		System.err.println(customerOrders.size());

		List list = new ArrayList<>();
		List potentialCustomerOrdersl=new ArrayList<>();
		potentialCustomerOrdersl.addAll(customerOrders);
		for (CustomerOrder c : customerOrders) {
			String[] str = new String[3];
			str[0] = c.getAccountNumber();
			str[1] = c.getCustomerName();
			str[2] = c.getBuyerAddress();
			potentialCustomerOrdersl = (List) map.get(str);
			map.put(str, list);
		}

		List customerOrderEntryList = new ArrayList();
		if (map.size() > 0) {
			customerOrderEntryList.addAll(map.entrySet());
			for (Iterator iter = customerOrderEntryList.iterator(); iter.hasNext();) {
				Map.Entry customerOrderEntry = (Map.Entry) iter.next();
				List potentialCustomerOrders = (List) customerOrderEntry.getValue();
				Collections.sort(potentialCustomerOrders, new Comparator() {

					public int compare(Object obj1, Object obj2) {
						CustomerOrder customerOrder1 = (CustomerOrder) obj1;
						CustomerOrder customerOrder2 = (CustomerOrder) obj2;
						return customerOrder1.getCustomerOrderno().compareTo(customerOrder2.getCustomerOrderno());
					}

				});
			}
		}
		
		
		

		Collections.sort(customerOrderEntryList, new Comparator() {
			public int compare(Object obj1, Object obj2) {
				Map.Entry entry1 = (Map.Entry) obj1;
				Map.Entry entry2 = (Map.Entry) obj2;
				String[] potentialCustomerOrderInfo1 = (String[]) entry1.getKey();
				String accountNumber1 = potentialCustomerOrderInfo1[0];
				String customerName1 = potentialCustomerOrderInfo1[1];
				String buyerAddress1 = potentialCustomerOrderInfo1[2];
				String[] potentialCustomerOrderInfo2 = (String[]) entry2.getKey();
				String accountNumber2 = potentialCustomerOrderInfo2[0];
				String customerName2 = potentialCustomerOrderInfo2[1];
				String buyerAddress2 = potentialCustomerOrderInfo2[2];
				if (accountNumber1.compareTo(accountNumber2) > 0) {
					return 1;
				}
				if (accountNumber1.compareTo(accountNumber2) < 0) {
					return -1;
				}
				if (null != customerName1 && null != customerName2) {
					if (customerName1.compareTo(customerName2) > 0) {
						return 1;
					}
					if (customerName1.compareTo(customerName2) < 0) {
						return -1;
					}
				}
				if (buyerAddress1.compareTo(buyerAddress2) > 0) {
					return 1;
				}
				if (buyerAddress1.compareTo(buyerAddress2) < 0) {
					return -1;
				}
				return 0;
			}

		});
		System.err.println(customerOrderEntryList.size());
	}

}

class CustomerOrder {
	private Long customerOrderno;
	private String accountNumber;
	private String customerName;
	private String buyerAddress;
	private int age;

	public CustomerOrder(Long customerOrderno, String accountNumber, String customerName, String buyerAddress,
			int age) {
		this.customerOrderno = customerOrderno;
		this.accountNumber = accountNumber;
		this.customerName = customerName;
		this.buyerAddress = buyerAddress;
		this.age = age;
	}

	public String getAccountNumber() {
		return accountNumber;
	}

	public int getAge() {
		return age;
	}

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

	public void setAccountNumber(String accountNumber) {
		this.accountNumber = accountNumber;
	}

	public String getCustomerName() {
		return customerName;
	}

	public void setCustomerName(String customerName) {
		this.customerName = customerName;
	}

	public String getBuyerAddress() {
		return buyerAddress;
	}

	public void setBuyerAddress(String buyerAddress) {
		this.buyerAddress = buyerAddress;
	}

	public Long getCustomerOrderno() {
		return customerOrderno;
	}

	public void setCustomerOrderno(Long customerOrderno) {
		this.customerOrderno = customerOrderno;
	}

}
//返回值是数组的形式,并且如果对象一样就会返回一样的值

[[Ljava.lang.String;@1e18a62b=[com.swfarm.biz.chain.bo.CustomerOrder@2da9f009[order id: =4028802d5f9e5000015f9e5ac184001c], com.swfarm.biz.chain.bo.CustomerOrder@6fcdf64a[order id: =4028802d5f9e5000015f9e5ac565001e]],

[Ljava.lang.String;@3d159e0c=[com.swfarm.biz.chain.bo.CustomerOrder@3ae4ad9e[order id: =402882445fc291fb015fc2e78bf900d2], com.swfarm.biz.chain.bo.CustomerOrder@7b427e46[order id: =402882445fe289dd015fe2a98c32001d]],

[Ljava.lang.String;@6445607c=[com.swfarm.biz.chain.bo.CustomerOrder@4a7064e2[order id: =40288244615516b301615518c5e2002f], com.swfarm.biz.chain.bo.CustomerOrder@18ef579c[order id: =40288244615516b301615518c8460033]],

[Ljava.lang.String;@6c1a052=[com.swfarm.biz.chain.bo.CustomerOrder@960cf8e[order id: =4028824460811dc001608126edd80002], com.swfarm.biz.chain.bo.CustomerOrder@32da7871[order id: =402882446081697d0160816c23ca0002], com.swfarm.biz.chain.bo.CustomerOrder@25195ccc[order id: =402882446081697d016081761b560006]]]