使用getObjectMapper().readValue 方法将字符串反序列化出现问题

Question

public static T getObjectFromJson(String json, TypeReference valueTypeRef) {
try {

    return getObjectMapper().readValue(json, valueTypeRef);
} catch (Exception e) {
    throw new RuntimeException(e);
}

}

报错信息
java.lang.RuntimeException: com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of java.util.ArrayList out of START_OBJECT token
at [Source: (String)"[{"default_value_type":"","display_condition":null,"enable_default_value":false,"id":"widget16518922297380001","name":"关联审批","printable":false,"required":true,"type":"connect","widget_default_value":""},{"default_value_type":"","display_condition":null,"enable_default_value":false,"id":"widget16518922368540001","name":"联系人","printable":true,"required":true,"type":"contact","widget_default_value":""},{"default_value_type":"","display_condition":null,"enable_default_value":false,"id":"widget165189"[truncated 2142 chars]; line: 1, column: 1920] (through reference chain: java.util.ArrayList[5]->cn.com.lundong.feishu.approval.request.result.ApprovalFormFieldResult["option"])

Answer 1

json字符串含有数组，核查下反序列化接收对象是否定义对应类型的参数

例如：

//反序列化方法
    public static <T> T decode(String json, TypeReference<T> typeReference)
            throws JsonParseException, JsonMappingException, IOException {
        return (T) objectMapper.readValue(json, typeReference);
    }

@Data
public class OutModel {

    @JsonProperty("test")
    private List<InnerModel> test;
}


@Data
public class InnerModel {

    @JsonProperty("default_value_type")
    private String defaultValueType;
}

//测试调用
String jsonstr = "{\n" +
                "\t\"test\": [{\n" +
                "\t\t\"default_value_type\": \"123\"\n" +
                "\t},\n" +
                "\t{\n" +
                "\t\t\"default_value_type\": \"456\"\n" +
                "\t}]\n" +
                "}";
        OutModel list = null;
        try {
            list = JsonUtil.decode(jsonstr, new TypeReference<OutModel>() {
            });
        } catch (IOException e) {
            e.printStackTrace();
        }
        List<InnerModel> inner = list.getTest();
        inner.forEach(innerModel -> {
            System.out.println(innerModel.getDefaultValueType());
        });