SpringBoot使用redis生成订单号的实现示例

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
 
import java.text.SimpleDateFormat;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.temporal.ChronoUnit;
import java.util.Date;
import java.util.concurrent.TimeUnit;
 
/**
 * redis的increment 递增方法 | 处理防重复和并发问题
 */
@Component
public class OrderNumberCodeUtils {
    private static final String PREFIX = "DD";
    private static final String DATE_FORMAT = "yyyyMMdd";
    private static final String ORDER_SERIAL_NUMBER = "order_serial_number";
 
    private static RedisTemplate redisTemplate;
 
    @Autowired
    public void redisTemplate(RedisTemplate redisTemplate){
        OrderNumberCodeUtils.redisTemplate = redisTemplate;
    }
 
    public static String generateOrderNumber() {
 
        StringBuffer stringBuffer = new StringBuffer();
        stringBuffer.append(PREFIX);
        // 获取当前日期
        SimpleDateFormat dateFormat = new SimpleDateFormat(DATE_FORMAT);
        String currentDate = dateFormat.format(new Date());
        stringBuffer.append(currentDate);
        // 获取流水号
        Long increment = redisTemplate.opsForValue().increment(ORDER_SERIAL_NUMBER, 1);
		
		/**
		 * 返回值过期时间，单位为秒。
		 * 如果返回-2，则表示该键不存在；
		 * 如果返回-1，则表示该键没有设置过期时间；
		 */
		Long expire = redisTemplate.getExpire(ORDER_SERIAL_NUMBER, TimeUnit.SECONDS);
		if(expire == -1){
			// 获取距离当天结束的秒数
			LocalDateTime endOfDay = LocalDate.now().atTime(23, 59, 59);
			long secondsToMidnight = LocalDateTime.now().until(endOfDay, ChronoUnit.SECONDS);
            //初始设置过期时间
            redisTemplate.expire(ORDER_SERIAL_NUMBER, secondsToMidnight, TimeUnit.SECONDS);
        }
        String format = String.format("%05d", increment);
        stringBuffer.append(format);
        return stringBuffer.toString();
    }
}