解决bug:HttpMessageNotReadableException: JSON parse error: java.lang.Object is not an enum type

àì夳堔傛蜴生んèń 2022-01-27 14:45 1500阅读 0赞

# 完整的问题如下: #

swagger模拟前端请求的json格式为:

{
      "enabled": true,
      "identification": "string",
      "name": "string",
      "onwerRoleGroups": [
        null
      ],
      "parentId": 0,
      "remark": "string",
      "roleCategory": "NORMAL",
      "root": true,
      "text": "string",
      "totalResources": [
        {
          "enabled": true,
          "id": 0,
          "operations": [
            "RETRIEVE"
          ],
          "permissionModule": {
            "enabled": true,
            "identification": "string",
            "menu": true,
            "name": "string",
            "ownerType": "ROLE",
            "parentId": 0,
            "rank": 0,
            "remark": "string",
            "root": true,
            "uris": [
              "string"
            ]
          },
          "rank": 0
        }
      ]
    }

问题出在:

"operations": [
            "RETRIEVE"
          ]

详细的报错为:

— Resolved \[org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: java.lang.Object is not an enum type; nested exception is com.fasterxml.jackson.databind.JsonMappingException: java.lang.Object is not an enum type (through reference chain: cn.ffcs.videoapp.web.security.permission.entity.PermissionRole\[“totalResources”\]->java.util.HashSet\[0\]->cn.ffcs.videoapp.web.security.permission.entity.PermissionResource\[“operations”\]->java.util.HashSet\[0\])\]  
分析的话应该是枚举和javabean识别的问题  
先做一个简单的DEMO测试一下  
**下面的代码是controller**

@ApiOperation("呵呵")
        @PostMapping("/aaa")
        public String addRole1(@RequestBody Person2 person2) {
            Set<Sex> sexs = person2.getSexs();
            System.out.println(person2.getName());
            for (Sex sex : sexs) {
                System.out.println(sex.getText());
            }
            return "ok";
        }

**下面的封装一个javabean,里面一个字段是Set<枚举>**

public class Person2 {
        private Set<Sex> sexs=new HashSet<>(0);
        private String name;
    
        public Set<Sex> getSexs() {
            return sexs;
        }
    
        public void setSexs(Set<Sex> sexs) {
            this.sexs = sexs;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    }

**这个是枚举**

public enum Sex {
        MAN("男"),WOMAN("女");
    
        private String text;
    
        Sex(String text) {
            this.text = text;
        }
    
        public String getText() {
            return text;
        }
    
        public void setText(String text) {
            this.text = text;
        }
    
        public static void main(String[] args) {
            System.out.println(Sex.MAN.getText());
        }
    }

swagger里面的json是:

{
      "name": "string",
      "sexs": [
        "MAN"
      ]
    }

结果可以显示  
![在这里插入图片描述][20190527084452922.png]  
结论是:普通的枚举类可以通过  
**"字段":\[“枚举的属性1”,“枚举的属性2”\]**  
入参给controller并进行解析  
但是同样的写法.复杂嵌套的java里面套java再套枚举就不行  
在网上查询资料:  
[https://blog.csdn.net/zhangfengaiCQ/article/details/82657926\#commentBox][https_blog.csdn.net_zhangfengaiCQ_article_details_82657926_commentBox]  
再枚举上加上注解  
@JSONType(serializeEnumAsJavaBean = true)  
（import com.alibaba.fastjson.annotation.JSONType;）  
@JsonFormat(shape = JsonFormat.Shape.OBJECT)  
（import com.fasterxml.jackson.annotation.JsonFormat;）  
然后再枚举类上加上这两个注解,发现就可以了

# 找一下为什么 #

@JSONType(serializeEnumAsJavaBean = true)  
作用:配置enum的序列化,可以加在类上,也可以在SerializeConfig 里面配置  
@JsonFormat(shape = JsonFormat.Shape.OBJECT)  
作用:  
(1)@JsonFormat 用来表示json序列化的一种格式或者类型，主要有下面几个常用的属性  
shape: 表示序列化后的一种类型

pattern: 表示日期的格式

timezone: 默认是GMT，中国需要GMT+8

locale: 根据位置序列化的一种格式  
(2)可用于controller返回给前端responsebody的时候把枚举转换为Object

# 参考资料 #

[https://segmentfault.com/q/1010000006935643?\_ea=1182544][https_segmentfault.com_q_1010000006935643_ea_1182544]  
[https://blog.csdn.net/u012326462/article/details/83019681][https_blog.csdn.net_u012326462_article_details_83019681]  
[https://blog.csdn.net/zhangfengaiCQ/article/details/82657926\#commentBox][https_blog.csdn.net_zhangfengaiCQ_article_details_82657926_commentBox]

# 思考测试了下.好像有点不对 #

@JSONType(serializeEnumAsJavaBean = true)好像是没用的  
只要@JsonFormat(shape = JsonFormat.Shape.OBJECT)就可以了  
本项目之前用的枚举类继承了的类里面已经加了@JsonFormat(shape = JsonFormat.Shape.OBJECT)  
本来是可以了.  
继承的类上加了

@JsonDeserialize(
        using = OptionEnumAwareDeserializer.class
    )
    @JsonFormat(
        shape = Shape.OBJECT
    )

public class OptionEnumAwareDeserializer extends JsonDeserializer<OptionEnumAware>

估计改变了json的反序列化的配置规则,所以导致错误  
这里序列化指 对象转json字符串  
反序列化指string的json转对象  
具体还是要去json反序列化配置里面去改

[20190527084452922.png]: /images/20220127/2c5b3a68855d4e10902505afe3b8db4d.png
[https_blog.csdn.net_zhangfengaiCQ_article_details_82657926_commentBox]: https://blog.csdn.net/zhangfengaiCQ/article/details/82657926#commentBox
[https_segmentfault.com_q_1010000006935643_ea_1182544]: https://segmentfault.com/q/1010000006935643?_ea=1182544
[https_blog.csdn.net_u012326462_article_details_83019681]: https://blog.csdn.net/u012326462/article/details/83019681