fix jackson annotation JsonFormat compatible, for issue #2836

core/src/main/java/com/alibaba/fastjson2/util/BeanUtils.java

@@ -693,12 +693,20 @@ public static boolean isWriteEnumAsJavaBean(Class clazz) {
 
             Class<? extends Annotation> annotationType = annotation.annotationType();
             String name = annotationType.getName();
-            if ("com.alibaba.fastjson.annotation.JSONType".equals(name)) {
-                BeanInfo beanInfo = new BeanInfo(JSONFactory.getDefaultObjectWriterProvider());
-                BeanUtils.annotationMethods(annotationType, method -> BeanUtils.processJSONType1x(beanInfo, annotation, method));
-                if (beanInfo.writeEnumAsJavaBean) {
-                    return true;
-                }
+            BeanInfo beanInfo = new BeanInfo(JSONFactory.getDefaultObjectWriterProvider());
+            switch (name) {
+                case "com.alibaba.fastjson.annotation.JSONType":
+                    BeanUtils.annotationMethods(annotationType, method -> BeanUtils.processJSONType1x(beanInfo, annotation, method));
+                    break;
+                case "com.fasterxml.jackson.annotation.JsonFormat":
+                    boolean useJacksonAnnotation = JSONFactory.isUseJacksonAnnotation();
+                    if (useJacksonAnnotation) {
+                        processJacksonJsonFormat(beanInfo, annotation);
+                    }
+                    break;
+            }
+            if (beanInfo.writeEnumAsJavaBean) {
+                return true;
             }
         }
 

core/src/test/java/com/alibaba/fastjson2/issues_2800/Issue2836.java

@@ -0,0 +1,53 @@
+package com.alibaba.fastjson2.issues_2800;
+
+import com.alibaba.fastjson2.JSON;
+import com.fasterxml.jackson.annotation.JsonFormat;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.Getter;
+import org.junit.jupiter.api.Test;
+
+import java.io.Serializable;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class Issue2836 {
+    @Getter
+    @JsonFormat(shape = JsonFormat.Shape.OBJECT)
+    public enum Type
+            implements Serializable {
+        A("1", "1"),
+        B("2", "2"),
+        C("3", "3");
+        private final String code;
+        private final String msg;
+
+        Type(String code, String msg) {
+            this.code = code;
+            this.msg = msg;
+        }
+    }
+
+    @AllArgsConstructor
+    @Data
+    public static class User
+            implements Serializable {
+        private String name;
+        private Type type;
+    }
+
+    @Test
+    public void test() throws Exception {
+        ObjectMapper objectMapper = new ObjectMapper();
+
+        User user = new User("test", Type.B);
+        String test = JSON.toJSONString(user);
+        String jacksonResult = objectMapper.writeValueAsString(user);
+        assertEquals(jacksonResult, test);
+        String jsonString = JSON.toJSONString(Type.A);
+        assertEquals(
+                objectMapper.writeValueAsString(Type.A),
+                jsonString);
+    }
+}