我正在使用 SpringBoot 和 Mongo 数据库,我正在尝试将嵌入式文档保存到数据库中。
我有这个模型:
配置文件.java
@Data
@Document
public class Profile {
public final City city;
public final String imageId;
public Profile(City city,
String imageId) {
this.city = city;
this.imageId = imageId;
}
@Override
public String toString() {
return "Profile{" +
", city=" + city +
", imageId='" + imageId + '\'' +
'}';
}
private static boolean atLeast(int numChars, String s) {
if (s == null) {
return false;
}
var str = s.strip();
return str.length() >= numChars;
}
public static ProfileBuilder builder() {
return new ProfileBuilder();
}
public static final class ProfileBuilder {
public City city;
public String imageId;
private ProfileBuilder() {
}
public ProfileBuilder withCity(City city) {
this.city = city;
return this;
}
public ProfileBuilder withImageId(String imageId) {
this.imageId = imageId;
return this;
}
public Profile build(){
return new Profile(city, imageId);
}
}
}
City.java
public class City {
public final String name;
public City(String name) {
this.name = name;
}
@Override
public String toString() {
return "City{" +
", name='" + name + '\'' +
'}';
}
}
ProfileController.java
@RequestMapping( method = RequestMethod.POST)
public Profile addUser(@RequestBody Profile profile) {
return profileService.addProfile(profile);
}
我和 postman 一起发送这个 JSON
{
"city":{
"name":"Atena"
},
"imageId" : "Doe",
}
}
但我收到以下错误:
"JSON parse error: Cannot construct instance of `domain.City` (although at least one Creator exists): cannot deserialize from Object value (no delegate- or property-based Creator);"
最佳答案
至少有两种解决方案。
- 将
@JsonCreator
添加到构造函数并将@JsonProperty
添加到其参数(以指示 Jackson 如何以正确的顺序将 JSON 项替换到构造函数中)
class Profile {
...
@JsonCreator
public Profile(@JsonProperty("city") City city,
@JsonProperty("imageId") String imageId) {
this.city = city;
this.imageId = imageId;
}
...
}
(+ 与 City 类相同)
- Un
final
类属性并提供默认的无参数构造函数(以及现有的全参数构造函数)。
class Profile {
public City city;
public String imageId;
public Profile() {
}
public Profile(City city, String imageId) {
this.city = city;
this.imageId = imageId;
}
}
(+ 与 City 类相同)
测试
class Test {
public static void main(String[] args) throws JsonProcessingException {
String json = "{\"city\":{\"name\":\"Atena\"},\"imageId\":\"Doe\"}";
Profile p = new ObjectMapper().readValue(json, Profile.class);
System.out.println(p);
}
}
输出:
Profile{, city=City{, name='Atena'}, imageId='Doe'}
关于java - "JSON 解析错误 : Cannot construct instance of (although at least one Creator exists): cannot deserialize from Object value - SpringBoot,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/69538090/