java生成数字001到999的2种方法(亲测)

亦凉 2023-09-23 22:34 83阅读 0赞

package test;  
  
import java.sql.Timestamp;  
import java.text.SimpleDateFormat;  
import java.util.concurrent.atomic.AtomicInteger;  
  
public class IdTest \{  
  
private AtomicInteger count = new AtomicInteger(1);  
private static final String JOBTBL\_RECORD\_ID = "D";  
private static final String PROCESS\_ID = "EBD01";  
private Timestamp now = getSystemTimestamp();  
  
public static void main(String\[\] args) \{  
// TODO 自動生成されたメソッド・スタブ  
  
IdTest idTest = new IdTest();  
// idTest.putong();  
  
idTest.xianCheng();  
  
System.out.println(idTest.getJobRequestId());  
\}  
  
//普通の方法  
public void putong() \{  
for (int i = 1; i <= 999; i++) \{  
if (i < 10) \{  
System.out.println("00" + i);  
\} else if (i >= 100) \{  
System.out.println(i);  
\} else  
System.out.println("0" + i);  
\}  
\}

//スレッドセーフ方法  
public void xianCheng() \{  
AtomicInteger count = new AtomicInteger(0);  
  
for (; (count.getAndIncrement()) < 999;) \{  
if (count.get() < 10) \{  
  
System.out.println("00" + count);  
\} else if (count.get() >= 100) \{  
System.out.println(count);  
\} else  
System.out.println("0" + count);  
\}  
\}  
  
private String getJobRequestId() \{  
  
StringBuilder builder = new StringBuilder();  
StringBuilder num = new StringBuilder();  
  
// 3桁の数字の採番処理。999になった場合は001から採番すること。  
if (count.get() > 999) \{  
count = new AtomicInteger(1);  
\}  
  
// 3桁の数字を採番処理。  
if (count.get() < 10) \{  
num.append("00").append(count.getAndIncrement());  
\} else if (count.get() >= 100) \{  
num.append(count.getAndIncrement());  
\} else \{  
num.append("0").append(count.getAndIncrement());  
\}  
  
// ジョブリクエストID日時部分.  
SimpleDateFormat format2 = new SimpleDateFormat("yyyyMMddHHmmssSSS");  
String date = format2.format(now);  
  
// 組み合わせる。  
builder.append(JOBTBL\_RECORD\_ID);  
builder.append(date);  
builder.append(PROCESS\_ID);  
builder.append(num);  
  
return builder.toString();  
\}  
  
  
/\*\*  
\* システム日時取得する.  
\*  
\* @return Current system timestamp.  
\*/  
private Timestamp getSystemTimestamp() \{  
  
return new Timestamp(System.currentTimeMillis());  
\}  
  
\}

来源：[java生成数字001到999的2种方法\_weixin\_37370093的博客-CSDN博客\_生成001到999的3位连续数字][java_001_999_2_weixin_37370093_-CSDN_001_999_3]

[java_001_999_2_weixin_37370093_-CSDN_001_999_3]: https://blog.csdn.net/weixin_37370093/article/details/75367658