有关Collection中sort排序-白红宇

有关Collection中sort排序

阅读量：7118 次

发布时间：2019-06-28

本文共 5738 字，大约阅读时间需要 19 分钟。

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
     
       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]]]

转载于:https://www.cnblogs.com/liushisaonian/p/8588422.html

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