订单号重复Bug

解决思路：

• 使用UUID(在第一次生成订单号时初始化一个)

• 使用redis记录一个增长ID

• 使用数据库表维护一个增长ID

• 应用所在的网络IP

• 应用所在的端口号

• 使用第三方算法(雪花算法等等)

• 使用进程ID(某种程度下是一个可行的方案)

 

代码片段

import org.apache.commons.lang3.RandomUtils;

import java.net.InetAddress;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

public class OrderGen2Test {

    /** 订单号生成 **/
    private static ZoneId ZONE_ID = ZoneId.of("Asia/Shanghai");
    private static final AtomicInteger SEQ = new AtomicInteger(1000);
    private static final DateTimeFormatter DF_FMT_PREFIX = DateTimeFormatter.ofPattern("yyMMddHHmmssSS");
    public static String generateOrderNo(){
        LocalDateTime dataTime = LocalDateTime.now(ZONE_ID);
        if(SEQ.intValue()>9990){
            SEQ.getAndSet(1000);
        }
        return  dataTime.format(DF_FMT_PREFIX)+ getLocalIpSuffix()+SEQ.getAndIncrement();
    }

    private volatile static String IP_SUFFIX = null;
    private static String getLocalIpSuffix (){
        if(null != IP_SUFFIX){
            return IP_SUFFIX;
        }
        try {
            synchronized (OrderGen2Test.class){
                if(null != IP_SUFFIX){
                    return IP_SUFFIX;
                }
                InetAddress addr = InetAddress.getLocalHost();
                //  172.17.0.4  172.17.0.199 ,
                String hostAddress = addr.getHostAddress();
                if (null != hostAddress && hostAddress.length() > 4) {
                    String ipSuffix = hostAddress.trim().split("\\.")[3];
                    if (ipSuffix.length() == 2) {
                        IP_SUFFIX = ipSuffix;
                        return IP_SUFFIX;
                    }
                    ipSuffix = "0" + ipSuffix;
                    IP_SUFFIX = ipSuffix.substring(ipSuffix.length() - 2);
                    return IP_SUFFIX;
                }
                IP_SUFFIX = RandomUtils.nextInt(10, 20) + "";
                return IP_SUFFIX;
            }
        }catch (Exception e){
            System.out.println("获取IP失败:"+e.getMessage());
            IP_SUFFIX =  RandomUtils.nextInt(10,20)+"";
            return IP_SUFFIX;
        }
    }


    public static void main(String[] args) {
        List<String> orderNos = Collections.synchronizedList(new ArrayList<String>());
        IntStream.range(0,8000).parallel().forEach(i->{
            orderNos.add(generateOrderNo());
        });

        List<String> filterOrderNos = orderNos.stream().distinct().collect(Collectors.toList());

        System.out.println("订单样例："+ orderNos.get(22));
        System.out.println("生成订单数："+orderNos.size());
        System.out.println("过滤重复后订单数："+filterOrderNos.size());
        System.out.println("重复订单数："+(orderNos.size()-filterOrderNos.size()));
    }
}