推土机参考副本不工作

我的实体由创建 jpa 当我从DB中获取实体并尝试使用推土机进行映射时,该工具和我有类似的DTO。

实体和DTO看起来像

class A                             class A1
        {                                   {
            private B b;                        private B1 b1;
            private C c;                        private C1 c;

            getter/setter                       getter/setter
        }

        class B                             class B1
        {                                   {                   
            private C c;                     private C1 c;

            getter/setter                       getter/setter
        }                                   }

        class C                             class C1
        {                                   {           
            private A a;                    private A1 a;
            private B b;                    private B1 b;

            getter/setter                   getter/setter
        }                                   }

推土机映射文件如下所示:

<mapping>
        <class-a>com.entity.A</class-a>
        <class-b>com.dto.A1</class-b>         
          <field copy-by-reference="true">
            <a>b</a>
            <b>b1</b>
          </field>
          <field copy-by-reference="true">
            <a>c</a>
            <b>c1</b>
          </field>
        </mapping>  

我有个例外,比如:

org.dozer.MappingException: Illegal object type for the method 'setb1'. 
 Expected types: 
com.dto.B1
 Actual types: 
com.entity.B

我对Dozer很陌生,请帮我解决这个问题