code: public Class getGetClass(GetExecutor getExecutor, Class srcRefClass, Class getResultClass) {
          // 设置为自动提取的targetClasss
          if (getExecutor instanceof MapGetExecutor) {
              if (getResultClass != null) {
                  return getResultClass;// 优先设置为getResult的class对象
              }
          } else if (getExecutor instanceof FastPropertyGetExecutor) {
              return ((FastPropertyGetExecutor) getExecutor).getMethod().getReturnType(); // 获取getExecutor方法的返回结果类型
          } else if (getExecutor instanceof PropertyGetExecutor) {
              return ((PropertyGetExecutor) getExecutor).getMethod().getReturnType(); // 获取getExecutor方法的返回结果类型
          } else if (getExecutor instanceof FieldGetExecutor) {
              return ((FieldGetExecutor) getExecutor).getField().getType(); // 获取属性的类型
          } else if (getExecutor instanceof ThisSymbolGetExecutor) {
              return srcRefClass; // 返回对应src的类型
          }
  
          return null;
          // throw new BeanMappingException("unknow GetExecutor");
      }
docs: 根据executor返回对应的参数类型