[ISSUE #11994]修复HttpRequestInstanceBuilderTest出现的空指针问题，优化SnowFlakeInstanceIdGenerator初始化流程

naming/src/main/java/com/alibaba/nacos/naming/pojo/instance/SnowFlakeInstanceIdGenerator.java

@@ -31,13 +31,28 @@
 public class SnowFlakeInstanceIdGenerator implements InstanceIdGenerator {
 
  private static final SnowFlowerIdGenerator SNOW_FLOWER_ID_GENERATOR = new SnowFlowerIdGenerator();
-
- static {
- SNOW_FLOWER_ID_GENERATOR.init();
+
+ private static volatile boolean initialize = false;
+
+ private static final Object LOCK = new Object();
+
+ /**
+ * initialize the workerId and ensure that it is only initialized once.
+ */
+ private void ensureWorkerIdInitialization() {
+ if (!initialize) {
+ synchronized (LOCK) {
+ if (!initialize) {
+ SNOW_FLOWER_ID_GENERATOR.init();
+ initialize = true;
+ }
+ }
+ }
  }
- 
+
  @Override
  public String generateInstanceId(Instance instance) {
+ ensureWorkerIdInitialization();
  return SNOW_FLOWER_ID_GENERATOR.nextId() + NAMING_INSTANCE_ID_SPLITTER
  + instance.getClusterName() + NAMING_INSTANCE_ID_SPLITTER
  + instance.getServiceName();

naming/src/test/java/com/alibaba/nacos/naming/pojo/instance/HttpRequestInstanceBuilderTest.java

@@ -21,12 +21,14 @@
 import com.alibaba.nacos.api.naming.pojo.Instance;
 import com.alibaba.nacos.common.spi.NacosServiceLoader;
 import com.alibaba.nacos.naming.misc.UtilsAndCommons;
+import com.alibaba.nacos.sys.env.EnvUtil;
 import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.junit.MockitoJUnitRunner;
+import org.springframework.core.env.StandardEnvironment;
 
 import javax.servlet.http.HttpServletRequest;
 
@@ -54,6 +56,7 @@ public class HttpRequestInstanceBuilderTest {
  @BeforeClass
  public static void setUpBeforeClass() {
  NacosServiceLoader.load(InstanceExtensionHandler.class);
+ EnvUtil.setEnvironment(new StandardEnvironment());
  }
 
  @Before