diff --git a/plusone-basic/plusone-basic-infrastructure/src/main/java/xyz/zhouxy/plusone/jdbc/JdbcFactory.java b/plusone-basic/plusone-basic-infrastructure/src/main/java/xyz/zhouxy/plusone/jdbc/JdbcFactory.java
index aa27867..8a10056 100644
--- a/plusone-basic/plusone-basic-infrastructure/src/main/java/xyz/zhouxy/plusone/jdbc/JdbcFactory.java
+++ b/plusone-basic/plusone-basic-infrastructure/src/main/java/xyz/zhouxy/plusone/jdbc/JdbcFactory.java
@@ -16,17 +16,19 @@ import xyz.zhouxy.plusone.spring.SpringContextHolder;
  */
 public final class JdbcFactory {
 
-    private static final ApplicationContext CONTEXT = SpringContextHolder.getContext();
+    private static final ApplicationContext SPRING_APPLICATION_CONTEXT = SpringContextHolder.getContext();
+    private static final JdbcTemplate JDBC_TEMPLATE = SPRING_APPLICATION_CONTEXT.getBean(JdbcTemplate.class);
+    private static final NamedParameterJdbcTemplate NAMED_PARAMETER_JDBC_TEMPLATE = SPRING_APPLICATION_CONTEXT.getBean(NamedParameterJdbcTemplate.class);
 
     private JdbcFactory() {
         throw new IllegalStateException("Utility class");
     }
 
     public static JdbcTemplate getJdbcTemplate() {
-        return CONTEXT.getBean(JdbcTemplate.class);
+        return JDBC_TEMPLATE;
     }
 
     public static NamedParameterJdbcTemplate getNamedParameterJdbcTemplate() {
-        return CONTEXT.getBean(NamedParameterJdbcTemplate.class);
+        return NAMED_PARAMETER_JDBC_TEMPLATE;
     }
 }
diff --git a/plusone-basic/plusone-basic-infrastructure/src/main/java/xyz/zhouxy/plusone/spring/SpringContextHolder.java b/plusone-basic/plusone-basic-infrastructure/src/main/java/xyz/zhouxy/plusone/spring/SpringContextHolder.java
index 089cee5..b6d4046 100644
--- a/plusone-basic/plusone-basic-infrastructure/src/main/java/xyz/zhouxy/plusone/spring/SpringContextHolder.java
+++ b/plusone-basic/plusone-basic-infrastructure/src/main/java/xyz/zhouxy/plusone/spring/SpringContextHolder.java
@@ -4,15 +4,13 @@ import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
-public class SpringContextHolder {
+public enum SpringContextHolder {
+
+    INSTANCE
+    ;
 
     private ApplicationContext context;
 
-    private static final SpringContextHolder INSTANCE = new SpringContextHolder();
-
-    private SpringContextHolder() {
-    }
-
     public static ApplicationContext getContext() {
         return INSTANCE.context;
     }