diff --git a/mybatis-flex-core/src/main/java/com/mybatisflex/core/audit/DefaultMessageFactory.java b/mybatis-flex-core/src/main/java/com/mybatisflex/core/audit/DefaultMessageFactory.java
index 541a44e6..55d9b19a 100644
--- a/mybatis-flex-core/src/main/java/com/mybatisflex/core/audit/DefaultMessageFactory.java
+++ b/mybatis-flex-core/src/main/java/com/mybatisflex/core/audit/DefaultMessageFactory.java
@@ -25,8 +25,8 @@ import java.util.Enumeration;
  */
 public class DefaultMessageFactory implements MessageFactory {
 
-    private String platform = "mybatis-flex";
-    private String hostIp = getHostIp();
+    private final String platform = "mybatis-flex";
+    private final String hostIp = getHostIp();
 
 
     @Override
diff --git a/mybatis-flex-core/src/main/java/com/mybatisflex/core/audit/ScheduledMessageCollector.java b/mybatis-flex-core/src/main/java/com/mybatisflex/core/audit/ScheduledMessageCollector.java
index 9e82ac62..b0860043 100644
--- a/mybatis-flex-core/src/main/java/com/mybatisflex/core/audit/ScheduledMessageCollector.java
+++ b/mybatis-flex-core/src/main/java/com/mybatisflex/core/audit/ScheduledMessageCollector.java
@@ -28,12 +28,12 @@ import java.util.concurrent.locks.ReentrantReadWriteLock;
  */
 public class ScheduledMessageCollector implements MessageCollector, Runnable {
 
-    private long period;
-    private ScheduledExecutorService scheduler;
-    private MessageReporter messageSender;
+    private final long period;
+    private final ScheduledExecutorService scheduler;
+    private final MessageReporter messageSender;
 
-    private List<AuditMessage> messages = Collections.synchronizedList(new ArrayList<>());
-    private ReentrantReadWriteLock rrwLock = new ReentrantReadWriteLock();
+    private final List<AuditMessage> messages = Collections.synchronizedList(new ArrayList<>());
+    private final ReentrantReadWriteLock rrwLock = new ReentrantReadWriteLock();
 
     public ScheduledMessageCollector() {
         this(10, new ConsoleMessageReporter());
diff --git a/mybatis-flex-core/src/main/java/com/mybatisflex/core/audit/http/HttpMessageReporter.java b/mybatis-flex-core/src/main/java/com/mybatisflex/core/audit/http/HttpMessageReporter.java
index ace10e3d..c2bb87bc 100644
--- a/mybatis-flex-core/src/main/java/com/mybatisflex/core/audit/http/HttpMessageReporter.java
+++ b/mybatis-flex-core/src/main/java/com/mybatisflex/core/audit/http/HttpMessageReporter.java
@@ -22,9 +22,9 @@ import java.util.List;
 
 public class HttpMessageReporter implements MessageReporter {
 
-    private String endpoint;
-    private String secretKey;
-    private JSONFormatter jsonFormatter;
+    private final String endpoint;
+    private final String secretKey;
+    private final JSONFormatter jsonFormatter;
 
     public HttpMessageReporter(String endpoint, String secretKey, JSONFormatter jsonFormatter) {
         this.endpoint = endpoint;
diff --git a/mybatis-flex-core/src/main/java/com/mybatisflex/core/datasource/DataSourceBuilder.java b/mybatis-flex-core/src/main/java/com/mybatisflex/core/datasource/DataSourceBuilder.java
index 3734b619..5e718d70 100644
--- a/mybatis-flex-core/src/main/java/com/mybatisflex/core/datasource/DataSourceBuilder.java
+++ b/mybatis-flex-core/src/main/java/com/mybatisflex/core/datasource/DataSourceBuilder.java
@@ -27,7 +27,7 @@ import java.util.Map;
 
 public class DataSourceBuilder {
 
-    private static Map<String, String> dataSourceAlias = new HashMap<>();
+    private static final Map<String, String> dataSourceAlias = new HashMap<>();
 
     static {
         dataSourceAlias.put("druid", "com.alibaba.druid.pool.DruidDataSource");
@@ -39,7 +39,7 @@ public class DataSourceBuilder {
         dataSourceAlias.put("dbcp2", "org.apache.commons.dbcp2.BasicDataSource");
     }
 
-    private Map<String, String> dataSourceProperties;
+    private final Map<String, String> dataSourceProperties;
 
     public DataSourceBuilder(Map<String, String> dataSourceProperties) {
         this.dataSourceProperties = dataSourceProperties;
@@ -49,11 +49,7 @@ public class DataSourceBuilder {
         String dataSourceClassName = null;
         String type = dataSourceProperties.get("type");
         if (StringUtil.isNotBlank(type)) {
-            if (dataSourceAlias.containsKey(type)) {
-                dataSourceClassName = dataSourceAlias.get(type);
-            } else {
-                dataSourceClassName = type;
-            }
+            dataSourceClassName = dataSourceAlias.getOrDefault(type, type);
         } else {
             dataSourceClassName = detectDataSourceClass();
         }