Spring Boot继承加载动态数据时JSON反序列化异常求助

问题背景 #

我尝试在Spring Boot中加载以下几种不同DataType的动态数据：

PLAIN_TEXT_INPUT("plain_text_input"),
RADIO_BUTTONS("radio_buttons"),
CHECKBOXES("checkboxes"),
SELECT("select")

抛出的异常 #

not marked as ignorable (3 known properties: "actionId", "type", "text"])
at [Source: REDACTED (StreamReadFeature.INCLUDE_SOURCE_IN_LOCATION disabled); line: 12, column: 37] (through reference chain: configuration$Body["prefix"]->Prefix["aLevel"]->java.util.ArrayList[0]->xxx.$WidgetBase["placeholder"])

实体类代码 #

@Data
public static class Prefix {
    @JsonProperty("aLevel")
    private List<WidgetBase> aLevel;
}

@Data
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type")
@JsonSubTypes({
    @JsonSubTypes.Type(value = TextInput.class, name = "plain_text_input"),
    @JsonSubTypes.Type(value = RadioGroup.class, name = "radio_buttons"),
    @JsonSubTypes.Type(value = Select.class, name = "select"),
    @JsonSubTypes.Type(value = CheckBoxGroup.class, name = "checkboxes")
})
public static class WidgetBase  {
    @JsonProperty("actionId")
    private String actionId;
    @JsonProperty("type")
    private DataType type;
    @JsonProperty("text")
    private String text;
}
@Data
public static class TextInput extends WidgetBase {
    @JsonProperty("placeholder")
    private String placeholder;
    @JsonProperty("description")
    private String description;
}

@Data
public static class CheckBoxGroup extends WidgetBase {
    @JsonProperty("options")
    private List<CheckBoxOption> option_items;
}

@Data
public static class Select extends WidgetBase {
    @JsonProperty("selected_item")
    private Option selected_item;
    @JsonProperty("select_items")
    private List<Option> select_items;
}

@Data
public static class Option  {
    @JsonProperty("text")
    private String text;
    @JsonProperty("value")
    private String value;
}

请求Payload示例 #

"prefix":{
    "aLevel":[{
        "actionId":"plain_text_input_3",
        "type":"plain_text_input",
        "text":"Account ID",
        "placeholder":"Input your Account ID",
        "description":"Please enter the Account ID"
    },{
        "actionId":"radio_group_action_3",
        "type":"radio_buttons",
        "text":"Radio Select",
        "initial_option":{"text":"Radio 1","value":"value1"},
        "option_items":[{
            "text":"Option 1","value":"value1"
        },{
            "text":"Option 2","value":"value2"
        },{
            "text":"Option 3","value":"value3"
        }]
    },{
        "actionId":"checkbox_action_3",
        "text":"Checkbox Group",
        "type":"checkboxes",
        "options":[{
            "text":"Option 1","value":"value1","initial_selected":true
        }]
    },{
        "actionId":"select_action_3",
        "type":"select",
        "text":"This is static select label",
        "selected_item":{"text":"Option 1","value":"value1"},
        "select_items":[{
            "text":"Option 1","value":"value1"
        },{
            "text":"Option 2","value":"value2"
        },{
            "text":"Option 3","value":"value3"
        }]
    }]
}

解决方案 #

问题根源 #

异常提示placeholder字段在WidgetBase中未被识别，说明Jackson没有正确根据type字段将JSON映射到对应的子类，而是用父类WidgetBase解析所有字段，导致子类独有的字段被判定为未知属性。

修复步骤 #

1. 校验枚举与子类映射的一致性
   确保DataType枚举的字符串值和@JsonSubTypes.Type中指定的name完全匹配，比如PLAIN_TEXT_INPUT的枚举值必须是"plain_text_input"，否则Jackson无法匹配到对应子类。

2. 修正实体类的字段与Payload匹配问题

   • CheckBoxGroup类中，@JsonProperty("options")对应的字段名是option_items，但Payload中checkboxes类型的字段是"options"，需修正字段名：

     @Data
     public static class CheckBoxGroup extends WidgetBase {
         @JsonProperty("options")
         private List<CheckBoxOption> options; // 从option_items改为options
     }
     

   • 补充缺失的RadioGroup类：Payload中radio_buttons类型包含initial_option和option_items字段，实体类未定义该类，需添加：

     @Data
     public static class RadioGroup extends WidgetBase {
         @JsonProperty("initial_option")
         private Option initialOption;
         @JsonProperty("option_items")
         private List<Option> optionItems;
     }
     

   • 补充缺失的CheckBoxOption类：Payload中checkboxes的options包含initial_selected字段，需定义该类：

     @Data
     public static class CheckBoxOption extends Option {
         @JsonProperty("initial_selected")
         private boolean initialSelected;
     }
     

3. 添加未知字段忽略（可选）
   如果Payload可能存在未定义的字段，可在WidgetBase上添加@JsonIgnoreProperties(ignoreUnknown = true)，避免因额外字段抛出异常：

   @Data
   @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type")
   @JsonSubTypes({...})
   @JsonIgnoreProperties(ignoreUnknown = true)
   public static class WidgetBase  {
       // 原有字段
   }
   

4. 验证Jackson配置
   确保Spring Boot默认的Jackson配置未被修改，默认配置支持多态类型解析，若有自定义配置需保证未禁用相关多态处理特性。

内容的提问来源于stack exchange，提问作者pintekus