!121 自动获取jar的版本号进行banner的打印

Merge pull request !121 from 与或非/N/A

liteflow-core/src/main/java/com/yomahub/liteflow/util/LOGOPrinter.java

@@ -31,7 +31,8 @@ public class LOGOPrinter {
 	}
 
 	private static String getVersion(){
-		Package pkg = LOGOPrinter.class.getPackage();
-		return (pkg != null) ? pkg.getImplementationVersion() : "DEV";
+		return Optional.ofNullable(LOGOPrinter.class.getPackage())
+				.map(Package::getImplementationVersion)
+				.orElse("DEV");
 	}
 }