平时项目中只要涉及表，那么一定能接触到众多各式各样的ID编号，博主整理一些常用的ID格式，整合一个ID生成工具类，供大家参考，如果有什么不足指出，烦请留言批评指正，尽量改正，感激不尽。
目前包括ID生成规则：
- 根据时间获取编号
- 根据时间+机器码+后面累加的位数组成的编号
- 根据时间+机器码+后面随机数组成的编号
- 根据前缀+累加位数
- 根据前缀+时间
- 根据后缀+累加位数
- 根据后缀+时间
简单的使用方法：
public static void main(String[] args) {
IDUtil idUtil = new IDUtil("yyyyMMddHHmmssSSS");//yyyy-MM-dd HH:mm:ss：SSS
for (int i = 0; i < 10; i++) {
System.out.println(idUtil.generatedNoByFormatDateAndRandom(5,"5"));
}
}时间格式在创建对象时传入。在集群中使用应传入机器码或唯一标识作为唯一ID的根据。
更新
添加了多个可选的构造方法，来适应不同的生成规则。
IDUtil:
public class IDUtil {
private SimpleDateFormat sfd = new SimpleDateFormat("yyyyMMddHHmmssSSS");
private Set<Integer> randomSet = new HashSet<Integer>();
private String dateFlag;
private int sequence;
public IDUtil() {
this.sfd = new SimpleDateFormat("yyyyMMddHHmmssSSS");
this.dateFlag = this.sfd.format(new Date());
this.sequence = 0;
}
public IDUtil(String format) {
this.sfd = new SimpleDateFormat(format);
this.dateFlag = this.sfd.format(new Date());
this.sequence = 0;
}
public IDUtil(int sequence) {
this.sequence = sequence;
}
public String generatedNoByFormatDate(){
return this.generatedNoByFormatDate(null);
}
public String generatedNoByFormatDateAndNum(int digits){
return this.generatedNoByFormatDateAndNum(digits, null);
}
public String generatedNoByFormatDateAndRandom(int randomDigits){
return this.generatedNoByFormatDateAndRandom(randomDigits, null);
}
public String generatedNoByPrefix(String prefix, int digits){
return this.generatedNoByPrefix(prefix, digits, null);
}
public String generatedNoByDateAndPrefix(String prefix){
return this.generatedNoByDateAndPrefix(prefix, null);
}
public String generatedNoBySuffix(String suffix, int digits){
return this.generatedNoBySuffix(suffix, digits, null);
}
public String generatedNoByDateAndSuffix(String suffix){
return this.generatedNoByDateAndSuffix(suffix, null);
}
public String generatedNoByFormatDate(String machine){
String formatDate = this.sfd.format(new Date());
if (Objects.nonNull(machine)){
return formatDate + machine;
}
return formatDate;
}
public String generatedNoByFormatDateAndNum(int digits, String machine){
String no = "";
String formatDate = this.sfd.format(new Date());
if (this.dateFlag.equals(formatDate)){
this.sequence ++;
}else {
this.sequence = 0;
}
if (Objects.nonNull(machine)){
no = formatDate + machine + String.format("%0"+digits+"d", this.sequence);
}else {
no = formatDate + String.format("%0"+digits+"d", this.sequence);
}
return no;
}
public String generatedNoByFormatDateAndRandom(int randomDigits, String machine){
String no = "";
String formatDate = this.sfd.format(new Date());
StringBuffer sb = new StringBuffer("9");
for (int i = 1; i < randomDigits; i++) {
sb.append("9");
}
Random random = new Random();
int randomNum = 0;
do {
randomNum = random.nextInt(Integer.valueOf(sb.toString()));
}while (this.randomSet.contains(randomNum));
randomSet.add(randomNum);
if (Objects.nonNull(machine)){
no = formatDate + machine + String.format("%0"+randomDigits+"d", randomNum);
}else {
no = formatDate + String.format("%0"+randomDigits+"d", randomNum);
}
return no;
}
public String generatedNoByPrefix(String prefix, int digits, String machine){
String no = "";
this.sequence ++;
if (Objects.nonNull(machine)){
no = prefix + machine + String.format("%0"+digits+"d", this.sequence);
}else {
no = prefix + String.format("%0"+digits+"d", this.sequence);
}
return no;
}
public String generatedNoByDateAndPrefix(String prefix, String machine){
String no = "";
String formatDate = this.sfd.format(new Date());
if (Objects.nonNull(machine)){
no = prefix + formatDate + machine;
}else {
no = prefix + formatDate;
}
return no;
}
public String generatedNoBySuffix(String suffix, int digits, String machine){
String no = "";
this.sequence ++;
if (Objects.nonNull(machine)){
no = machine + String.format("%0"+digits+"d", this.sequence) + suffix;
}else {
no = String.format("%0"+digits+"d", this.sequence) + suffix;
}
return no;
}
public String generatedNoByDateAndSuffix(String suffix, String machine){
String no = "";
String formatDate = this.sfd.format(new Date());
if (Objects.nonNull(machine)){
no = formatDate + machine + suffix;
}else {
no = formatDate + suffix;
}
return no;
}
}
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