参考snowflake算法，基本思路：
序列12位(更格式化的输出后，性能损耗导致每毫秒生成不了这么多，所以可以考虑减少这里的位,不过留着也并无影响)
机器位10位
毫秒为左移 22位
上述几个做或运算后得出一个唯一的数，转10进制后，最大10位，最小7位，string.format来统一为10,format性能影响，导致性能降低3倍左右
FilUtils不想用的话，1太机器可以直接考虑使用1，多机器根据代码配置id
代码如下:
package net.gitosc.lianqu1990.utils.code;
import net.gitosc.lianqu1990.utils.date.DateFormatUtils;
import net.gitosc.lianqu1990.utils.date.TimeMark;
import org.apache.commons.io.FileUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
public class OrderNoCenter {
public static final Logger logger = LoggerFactory.getLogger(OrderNoCenter.class);
private static final String WORKERID_PATH = "/etc/workerId";
private OrderNoCenter() {
}
private static class OrderNoCenterHolder{
private static OrderNoCenter instance = new OrderNoCenter();
}
public static OrderNoCenter getInstance() {
return OrderNoCenterHolder.instance;
}
private long workerId = 1;
private long sequence = 1;
private final long workerIdBits = 10L;
private final long maxWorkerId = -1L ^ (-1L << workerIdBits); //结果就是2的workerBits次方-1,能表示的最大数.全部1亦或10位0，就是0开头最后10位1
private final long sequenceBits = 12L;
private final long workerIdShift = sequenceBits;
private final long datacenterIdShift = sequenceBits + workerIdBits;
private final long sequenceMask = -1L ^ (-1L << sequenceBits);
private final long timestampLeftShift = sequenceBits + workerIdBits;
private long lastTimestamp = -1L;
public void initParam() {
// 从默认位置读取workerId,最大1024
try {
File conf = new File(WORKERID_PATH);
if(conf.exists()){
String str = FileUtils.readFileToString(conf);
workerId = Integer.parseInt(str);
}else{
logger.warn(" worker id not found,will use default value...");
}
} catch(Exception e){
e.printStackTrace();
}
logger.info(" worker id is {}",workerId);
if (workerId < 0 || workerId > maxWorkerId) {
throw new IllegalArgumentException("workerId is illegal: "
+ workerId);
}
}
public long getWorkerId() {
return workerId;
}
public long getTime() {
return System.currentTimeMillis();
}
public String create() {
return nextNo();
}
private synchronized String nextNo() {
long timestamp = timeGen();
// 时间错误
if (timestamp < lastTimestamp) {
throw new IllegalStateException("Clock moved backwards.");
}
// 当前毫秒内，则+1
if (lastTimestamp == timestamp) {
// 当前毫秒内计数满了，则等待下一秒
sequence = (sequence + 1) & sequenceMask;
if (sequence == 0) {
timestamp = tilNextMillis(lastTimestamp);
}
} else {
sequence = 0;
}
lastTimestamp = timestamp;
// ID偏移组合生成最终的ID，并返回ID,最大十位数
long id = ((timestamp % 1000) << timestampLeftShift) | (workerId << workerIdShift) | sequence;
String timestampStr = DateFormatUtils.NUMBER_FORMAT.format(timestamp);
return timestampStr+String.format("%010d",id);
}
private long tilNextMillis(long lastTimestamp) {
long timestamp = timeGen();
while (timestamp <= lastTimestamp) {
timestamp = timeGen();
}
return timestamp;
}
private long timeGen() {
return System.currentTimeMillis();
}
public static void main(String[] args){
for (int i = 0; i < 100; i++) {
System.out.println(OrderNoCenter.getInstance().create());
}
//性能测试
TimeMark mark = new TimeMark();
for (int i = 0; i < 1000000; i++) {
OrderNoCenter.getInstance().create();
}
mark.simplePrint();
mark.mark();
for (int i = 0; i < 1000000; i++) {
IdCenter.getInstance().getId();
}
mark.simplePrint();
}
}
缺少代码的话，请直接使用我的附件代码
