diff --git a/chat/core/src/main/java/com/tencent/supersonic/chat/parser/sql/llm/OutputFormat.java b/chat/core/src/main/java/com/tencent/supersonic/chat/parser/sql/llm/OutputFormat.java
index fda0031a1..5aefc16d0 100644
--- a/chat/core/src/main/java/com/tencent/supersonic/chat/parser/sql/llm/OutputFormat.java
+++ b/chat/core/src/main/java/com/tencent/supersonic/chat/parser/sql/llm/OutputFormat.java
@@ -24,11 +24,11 @@ public class OutputFormat {
             if (matcher.find()) {
                 schemaLinkOutput = matcher.group(1).trim();
             } else {
-                schemaLinkOutput = null;
+                schemaLinkOutput = "";
             }
         } catch (Exception e) {
             log.error("", e);
-            schemaLinkOutput = null;
+            schemaLinkOutput = "";
         }
         return schemaLinkOutput;
     }
diff --git a/chat/core/src/main/java/com/tencent/supersonic/chat/parser/sql/llm/TwoStepSqlGeneration.java b/chat/core/src/main/java/com/tencent/supersonic/chat/parser/sql/llm/TwoStepSqlGeneration.java
index d2614e751..fa0b5fdef 100644
--- a/chat/core/src/main/java/com/tencent/supersonic/chat/parser/sql/llm/TwoStepSqlGeneration.java
+++ b/chat/core/src/main/java/com/tencent/supersonic/chat/parser/sql/llm/TwoStepSqlGeneration.java
@@ -5,7 +5,6 @@ import com.tencent.supersonic.chat.config.OptimizationConfig;
 import com.tencent.supersonic.chat.query.llm.s2sql.LLMReq;
 import com.tencent.supersonic.chat.query.llm.s2sql.LLMReq.ElementValue;
 import com.tencent.supersonic.chat.query.llm.s2sql.LLMReq.SqlGenerationMode;
-import com.tencent.supersonic.common.util.ContextUtils;
 import com.tencent.supersonic.common.util.JsonUtil;
 import dev.langchain4j.data.message.AiMessage;
 import dev.langchain4j.model.chat.ChatLanguageModel;
@@ -33,6 +32,9 @@ public class TwoStepSqlGeneration implements SqlGeneration, InitializingBean {
     @Autowired
     private OptimizationConfig optimizationConfig;
 
+    @Autowired
+    private SqlPromptGenerator sqlPromptGenerator;
+
     @Override
     public String generation(LLMReq llmReq, String modelClusterKey) {
         String text2sqlCollectionName = optimizationConfig.getText2sqlCollectionName();
@@ -46,7 +48,6 @@ public class TwoStepSqlGeneration implements SqlGeneration, InitializingBean {
         List<String> fieldNameList = llmReq.getSchema().getFieldNameList();
         List<ElementValue> linking = llmReq.getLinking();
 
-        SqlPromptGenerator sqlPromptGenerator = ContextUtils.getBean(SqlPromptGenerator.class);
         String linkingPromptStr = sqlPromptGenerator.generateSchemaLinkingPrompt(queryText, modelName, fieldNameList,
                 linking, sqlExamples);