异常源代码

抛出异常的地方是BeanDeserializerBase中的deserializeFromObjectUsingNonDefault()方法

protected Object deserializeFromObjectUsingNonDefault(JsonParser p, DeserializationContext ctxt) throws IOException {
        JsonDeserializer<Object> delegateDeser = this._delegateDeserializer();
        if (delegateDeser != null) {
            return this._valueInstantiator.createUsingDelegate(ctxt, delegateDeser.deserialize(p, ctxt));
        } else if (this._propertyBasedCreator != null) {
            return this._deserializeUsingPropertyBased(p, ctxt);
        } else {
            return this._beanType.isAbstract() ? ctxt.handleMissingInstantiator(this.handledType(), p, "abstract type (need to add/enable type information?)", new Object[0]) : ctxt.handleMissingInstantiator(this._beanType.getRawClass(), p, "no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?)", new Object[0]);
        }
    }

分析

从返回的英文信息来看，应该是“没有合适的构造函数”引起的。但是实体类中又存在构造函数，但是没有无参构造函数，猜想应该是没有无参构造函数引起的。