java - Lombok 未创建默认构造函数导致 jackson-databinding 失败

Question

这个问题已经有答案了:

Lombok 1.18.0 and Jackson 2.9.6 not working together (5 个回答)

已关闭 4 年前。

我有一个 POJO

@Data
@AllArgsConstrcutor
class Test {

T field1,
T field2,
}

当我尝试使用 jackson-databind 2.9.3 反序列化它时，它是

failing com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of com.mypackage.Test (no Creators, like default construct, exist): cannot deserialize from Object value (no delegate- or property-based Creator) at [Source: (String)

Answer 1

@AllArgsConstructor 为类的每个字段创建一个带有参数的构造函数(因此，在您的情况下，您将得到 Test(T, T))。

对于默认构造函数，您应该添加@NoArgsConstructor注释:

@Data
@AllArgsConstrcutor // Won't be used by Jackson, but there's no harm in it, per-se
@NoArgsConstructor // Here!
class Test {
    T field1;
    T field2;
}