diff --git a/mybatis-plus-join-core/src/main/java/com/github/yulichang/toolkit/MPJReflectionKit.java b/mybatis-plus-join-core/src/main/java/com/github/yulichang/toolkit/MPJReflectionKit.java
index 772488b..3756b08 100644
--- a/mybatis-plus-join-core/src/main/java/com/github/yulichang/toolkit/MPJReflectionKit.java
+++ b/mybatis-plus-join-core/src/main/java/com/github/yulichang/toolkit/MPJReflectionKit.java
@@ -41,6 +41,7 @@ public final class MPJReflectionKit {
         PRIMITIVE_WRAPPER_TYPE_MAP.put(Integer.class, int.class);
         PRIMITIVE_WRAPPER_TYPE_MAP.put(Long.class, long.class);
         PRIMITIVE_WRAPPER_TYPE_MAP.put(Short.class, short.class);
+        PRIMITIVE_WRAPPER_TYPE_MAP.put(String.class, String.class);
         for (Map.Entry<Class<?>, Class<?>> entry : PRIMITIVE_WRAPPER_TYPE_MAP.entrySet()) {
             PRIMITIVE_TYPE_TO_WRAPPER_MAP.put(entry.getValue(), entry.getKey());
         }