ABAP面向对象编程

ABAP面向对象编程(OO)学习指南

一、基础概念

1.1 类与对象

类(Class)是对象的模板，定义了对象的属性和行为。对象(Object)是类的实例。

* 定义类
CLASS lcl_vehicle DEFINITION.
  PUBLIC SECTION.
    METHODS: constructor IMPORTING iv_type TYPE string
                                   iv_speed TYPE i,
             get_type RETURNING VALUE(rv_type) TYPE string,
             get_speed RETURNING VALUE(rv_speed) TYPE i,
             accelerate IMPORTING iv_increment TYPE i.
  PRIVATE SECTION.
    DATA: mv_type  TYPE string,
          mv_speed TYPE i.
ENDCLASS.

* 实现类
CLASS lcl_vehicle IMPLEMENTATION.
  METHOD constructor.
    mv_type  = iv_type.
    mv_speed = iv_speed.
  ENDMETHOD.

  METHOD get_type.
    rv_type = mv_type.
  ENDMETHOD.

  METHOD get_speed.
    rv_speed = mv_speed.
  ENDMETHOD.

  METHOD accelerate.
    mv_speed = mv_speed + iv_increment.
  ENDMETHOD.
ENDCLASS.

* 创建对象并使用
START-OF-SELECTION.
  DATA(lo_car) = NEW lcl_vehicle( iv_type = 'Car' iv_speed = 0 ).
  lo_car->accelerate( 60 ).
  WRITE: / lo_car->get_type( ), lo_car->get_speed( ).

1.2 可见性区域

区域	关键字	说明
公有	PUBLIC SECTION	类内外均可访问
保护	PROTECTED SECTION	类及其子类可访问
私有	PRIVATE SECTION	仅类内部可访问

1.3 实例成员与静态成员

CLASS lcl_counter DEFINITION.
  PUBLIC SECTION.
    CLASS-DATA: gv_total_count TYPE i.  " 静态属性(类级别)
    DATA: mv_instance_count TYPE i.     " 实例属性(对象级别)
    CLASS-METHODS: get_total RETURNING VALUE(rv_total) TYPE i.  " 静态方法
    METHODS: increment.                                          " 实例方法
ENDCLASS.

CLASS lcl_counter IMPLEMENTATION.
  METHOD increment.
    mv_instance_count = mv_instance_count + 1.
    gv_total_count    = gv_total_count + 1.
  ENDMETHOD.
  METHOD get_total.
    rv_total = gv_total_count.
  ENDMETHOD.
ENDCLASS.

1.4 CREATE 实例化控制

* CREATE PUBLIC: 任何地方均可实例化(默认)
CLASS lcl_public DEFINITION CREATE PUBLIC.
  ...
ENDCLASS.

* CREATE PRIVATE: 仅类内部可实例化(单例模式常用)
CLASS lcl_singleton DEFINITION CREATE PRIVATE.
  PUBLIC SECTION.
    CLASS-METHODS: get_instance RETURNING VALUE(ro_instance) TYPE REF TO lcl_singleton.
  PRIVATE SECTION.
    CLASS-DATA: go_instance TYPE REF TO lcl_singleton.
ENDCLASS.

CLASS lcl_singleton IMPLEMENTATION.
  METHOD get_instance.
    IF go_instance IS NOT BOUND.
      CREATE OBJECT go_instance.
    ENDIF.
    ro_instance = go_instance.
  ENDMETHOD.
ENDCLASS.

* CREATE PROTECTED: 仅类及其子类可实例化(工厂模式常用)
CLASS lcl_factory DEFINITION CREATE PROTECTED.
  ...
ENDCLASS.

---

二、继承与多态

2.1 继承(INHERITING FROM)

* 父类: 交通工具
CLASS lcl_vehicle DEFINITION.
  PUBLIC SECTION.
    METHODS: constructor IMPORTING iv_brand TYPE string,
             get_brand RETURNING VALUE(rv_brand) TYPE string,
             describe.  " 可被重写
  PROTECTED SECTION.
    DATA: mv_brand TYPE string.
ENDCLASS.

CLASS lcl_vehicle IMPLEMENTATION.
  METHOD constructor.
    mv_brand = iv_brand.
  ENDMETHOD.
  METHOD get_brand.
    rv_brand = mv_brand.
  ENDMETHOD.
  METHOD describe.
    WRITE: / 'This is a vehicle by', mv_brand.
  ENDMETHOD.
ENDCLASS.

* 子类: 汽车(继承自交通工具)
CLASS lcl_car DEFINITION INHERITING FROM lcl_vehicle.
  PUBLIC SECTION.
    METHODS: constructor IMPORTING iv_brand TYPE string
                                   iv_doors TYPE i,
             describe REDEFINITION.  " 重写父类方法
  PRIVATE SECTION.
    DATA: mv_doors TYPE i.
ENDCLASS.

CLASS lcl_car IMPLEMENTATION.
  METHOD constructor.
    super->constructor( iv_brand ).  " 调用父类构造方法
    mv_doors = iv_doors.
  ENDMETHOD.
  METHOD describe.
    WRITE: / mv_brand, 'car with', mv_doors, 'doors'.
  ENDMETHOD.
ENDCLASS.

2.2 抽象类与方法

CLASS lcl_shape DEFINITION ABSTRACT.
  PUBLIC SECTION.
    METHODS: constructor IMPORTING iv_name TYPE string,
             get_area ABSTRACT RETURNING VALUE(rv_area) TYPE f,  " 抽象方法,子类必须实现
             get_name RETURNING VALUE(rv_name) TYPE string.
  PROTECTED SECTION.
    DATA: mv_name TYPE string.
ENDCLASS.

CLASS lcl_shape IMPLEMENTATION.
  METHOD constructor.
    mv_name = iv_name.
  ENDMETHOD.
  METHOD get_name.
    rv_name = mv_name.
  ENDMETHOD.
ENDCLASS.

* 子类: 圆形
CLASS lcl_circle DEFINITION INHERITING FROM lcl_shape.
  PUBLIC SECTION.
    METHODS: constructor IMPORTING iv_name   TYPE string
                                   iv_radius TYPE f,
             get_area REDEFINITION.
  PRIVATE SECTION.
    DATA: mv_radius TYPE f.
ENDCLASS.

CLASS lcl_circle IMPLEMENTATION.
  METHOD constructor.
    super->constructor( iv_name ).
    mv_radius = iv_radius.
  ENDMETHOD.
  METHOD get_area.
    rv_area = 3.14159 * mv_radius * mv_radius.
  ENDMETHOD.
ENDCLASS.

2.3 最终类(FINAL)

CLASS lcl_utility DEFINITION FINAL.
  PUBLIC SECTION.
    CLASS-METHODS: format_date IMPORTING iv_date TYPE d
                               RETURNING VALUE(rv_formatted) TYPE string.
ENDCLASS.

CLASS lcl_utility IMPLEMENTATION.
  METHOD format_date.
    rv_formatted = |{ iv_date+0(4) }-{ iv_date+4(2) }-{ iv_date+6(2) }|.
  ENDMETHOD.
ENDCLASS.

2.4 多态与向上转型

DATA: lo_shape TYPE REF TO lcl_shape.

* 子类对象赋给父类引用(向上转型)
lo_shape = NEW lcl_circle( iv_name = 'Circle1' iv_radius = 5 ).
WRITE: / lo_shape->get_name( ), lo_shape->get_area( ).  " 运行时决定调用哪个get_area

---

三、接口(Interfaces)

3.1 定义与实现

* 定义接口
INTERFACE lif_printable.
  METHODS: print RETURNING VALUE(rv_text) TYPE string.
ENDINTERFACE.

INTERFACE lif_serializable.
  METHODS: serialize   RETURNING VALUE(rv_json) TYPE string,
           deserialize IMPORTING iv_json TYPE string.
ENDINTERFACE.

* 实现多个接口
CLASS lcl_report DEFINITION.
  PUBLIC SECTION.
    INTERFACES: lif_printable, lif_serializable.  " 实现两个接口
    METHODS: constructor IMPORTING iv_title TYPE string.
  PRIVATE SECTION.
    DATA: mv_title TYPE string.
ENDCLASS.

CLASS lcl_report IMPLEMENTATION.
  METHOD constructor.
    mv_title = iv_title.
  ENDMETHOD.
  METHOD lif_printable~print.
    rv_text = |Report: { mv_title }|.
  ENDMETHOD.
  METHOD lif_serializable~serialize.
    rv_json = |\{"title":"{ mv_title }"\}|.
  ENDMETHOD.
  METHOD lif_serializable~deserialize.
    " 简化解析
    mv_title = 'Deserialized Report'.
  ENDMETHOD.
ENDCLASS.

3.2 接口引用与多态

DATA: lo_printable TYPE REF TO lif_printable.

lo_printable = NEW lcl_report( 'Sales Report' ).
WRITE: / lo_printable->print( ).  " 通过接口调用

* 检查对象是否实现某接口
DATA(lo_report) = NEW lcl_report( 'Test' ).
IF lo_report IS INSTANCE OF lif_serializable.
  DATA(lo_serial) = CAST lif_serializable( lo_report ).
  WRITE: / lo_serial->serialize( ).
ENDIF.

3.3 接口组合(嵌套接口)

INTERFACE lif_component.
  INTERFACES: lif_printable, lif_serializable.
  " 组合接口,实现者需实现所有嵌套接口的方法
ENDINTERFACE.

---

四、事件编程

4.1 定义与触发事件

CLASS lcl_order DEFINITION.
  PUBLIC SECTION.
    EVENTS: order_created EXPORTING VALUE(ev_order_id) TYPE string,
            status_changed EXPORTING VALUE(ev_new_status) TYPE string.
    METHODS: constructor IMPORTING iv_order_id TYPE string,
             set_status IMPORTING iv_status TYPE string.
  PRIVATE SECTION.
    DATA: mv_order_id TYPE string,
          mv_status   TYPE string.
ENDCLASS.

CLASS lcl_order IMPLEMENTATION.
  METHOD constructor.
    mv_order_id = iv_order_id.
    mv_status   = 'NEW'.
    RAISE EVENT order_created EXPORTING ev_order_id = mv_order_id.
  ENDMETHOD.
  METHOD set_status.
    mv_status = iv_status.
    RAISE EVENT status_changed EXPORTING ev_new_status = mv_status.
  ENDMETHOD.
ENDCLASS.

4.2 事件处理

CLASS lcl_order_monitor DEFINITION.
  PUBLIC SECTION.
    METHODS: on_order_created FOR EVENT order_created OF lcl_order
               IMPORTING ev_order_id sender,
             on_status_changed FOR EVENT status_changed OF lcl_order
               IMPORTING ev_new_status sender.
ENDCLASS.

CLASS lcl_order_monitor IMPLEMENTATION.
  METHOD on_order_created.
    WRITE: / 'Order created:', ev_order_id.
  ENDMETHOD.
  METHOD on_status_changed.
    WRITE: / 'Status changed to:', ev_new_status.
  ENDMETHOD.
ENDCLASS.

* 注册事件处理器
START-OF-SELECTION.
  DATA(lo_monitor) = NEW lcl_order_monitor( ).
  DATA(lo_order)   = NEW lcl_order( 'ORD001' ).

  SET HANDLER lo_monitor->on_order_created  FOR lo_order.
  SET HANDLER lo_monitor->on_status_changed FOR lo_order.

  lo_order->set_status( 'PROCESSING' ).
  lo_order->set_status( 'COMPLETED' ).

4.3 静态事件

CLASS lcl_system_event DEFINITION.
  PUBLIC SECTION.
    CLASS-EVENTS: system_alert IMPORTING iv_message TYPE string.
    CLASS-METHODS: trigger_alert IMPORTING iv_message TYPE string.
ENDCLASS.

CLASS lcl_system_event IMPLEMENTATION.
  METHOD trigger_alert.
    RAISE EVENT system_alert EXPORTING iv_message = iv_message.
  ENDMETHOD.
ENDCLASS.

---

五、高级特性

5.1 RTTI 运行时类型识别

DATA: lo_type TYPE REF TO cl_abap_typedescr.

* 获取类型描述
lo_type = cl_abap_typedescr=>describe_by_data( sy-datum ).
WRITE: / 'Type:', lo_type->type_kind,
       / 'Kind:', lo_type->kind,
       / 'Length:', lo_type->length.

* 获取类的属性列表
DATA(lo_class) = CAST cl_abap_classdescr(
  cl_abap_typedescr=>describe_by_name( 'LCL_VEHICLE' ) ).

LOOP AT lo_class->attributes INTO DATA(ls_attr).
  WRITE: / ls_attr-name, ls_attr-is_class, ls_attr-is_read_only.
ENDLOOP.

* 动态创建对象
DATA: lo_dynamic TYPE REF TO object.
CREATE OBJECT lo_dynamic TYPE ('LCL_VEHICLE')
  EXPORTING iv_brand = 'Dynamic BMW'.

5.2 强制类型转换

DATA: lo_vehicle TYPE REF TO lcl_vehicle,
      lo_car     TYPE REF TO lcl_car.

lo_car = NEW lcl_car( iv_brand = 'BMW' iv_doors = 4 ).

* 向上转型(安全,隐式)
lo_vehicle = lo_car.

* 向下转型(需要显式转换)
TRY.
    lo_car = CAST lcl_car( lo_vehicle ).  " 安全转换
    WRITE: / lo_car->get_brand( ).
  CATCH cx_sy_move_cast_error INTO DATA(lx_error).
    WRITE: / 'Cast error:', lx_error->get_text( ).
ENDTRY.

5.3 泛型(Generics)

* 泛型类示例
CLASS lcl_stack DEFINITION.
  PUBLIC SECTION.
    METHODS: push IMPORTING iv_value TYPE any,
             pop  EXPORTING ev_value TYPE any,
             is_empty RETURNING VALUE(rv_empty) TYPE abap_bool.
  PRIVATE SECTION.
    DATA: mt_data TYPE REF TO data.
ENDCLASS.

CLASS lcl_stack IMPLEMENTATION.
  METHOD push.
    " 使用动态数据对象
    FIELD-SYMBOLS: <lt_data> TYPE ANY TABLE.
    ASSIGN mt_data->* TO <lt_data>.
    INSERT iv_value INTO TABLE <lt_data>.
  ENDMETHOD.
  METHOD pop.
    FIELD-SYMBOLS: <lt_data> TYPE ANY TABLE.
    ASSIGN mt_data->* <lt_data>.
    READ TABLE <lt_data> INDEX 1 INTO ev_value.
    DELETE <lt_data> INDEX 1.
  ENDMETHOD.
  METHOD is_empty.
    FIELD-SYMBOLS: <lt_data> TYPE ANY TABLE.
    ASSIGN mt_data->* TO <lt_data>.
    rv_empty = COND #( WHEN <lt_data> IS INITIAL THEN abap_true ELSE abap_false ).
  ENDMETHOD.
ENDCLASS.

---

六、设计模式实践

6.1 工厂模式(Factory Pattern)

INTERFACE lif_vehicle.
  METHODS: get_type RETURNING VALUE(rv_type) TYPE string.
ENDINTERFACE.

CLASS lcl_car DEFINITION.
  PUBLIC SECTION.
    INTERFACES lif_vehicle.
ENDCLASS.
CLASS lcl_car IMPLEMENTATION.
  METHOD lif_vehicle~get_type.
    rv_type = 'Car'.
  ENDMETHOD.
ENDCLASS.

CLASS lcl_truck DEFINITION.
  PUBLIC SECTION.
    INTERFACES lif_vehicle.
ENDCLASS.
CLASS lcl_truck IMPLEMENTATION.
  METHOD lif_vehicle~get_type.
    rv_type = 'Truck'.
  ENDMETHOD.
ENDCLASS.

CLASS lcl_vehicle_factory DEFINITION.
  PUBLIC SECTION.
    CLASS-METHODS: create IMPORTING iv_type TYPE string
                          RETURNING VALUE(ro_vehicle) TYPE REF TO lif_vehicle.
ENDCLASS.

CLASS lcl_vehicle_factory IMPLEMENTATION.
  METHOD create.
    ro_vehicle = SWITCH #( iv_type
      WHEN 'CAR'   THEN NEW lcl_car( )
      WHEN 'TRUCK' THEN NEW lcl_truck( ) ).
  ENDMETHOD.
ENDCLASS.

6.2 策略模式(Strategy Pattern)

INTERFACE lif_discount_strategy.
  METHODS: calculate IMPORTING iv_price TYPE p
                     RETURNING VALUE(rv_final) TYPE p.
ENDCLASS.

CLASS lcl_no_discount DEFINITION.
  PUBLIC SECTION.
    INTERFACES lif_discount_strategy.
ENDCLASS.
CLASS lcl_no_discount IMPLEMENTATION.
  METHOD lif_discount_strategy~calculate.
    rv_final = iv_price.
  ENDMETHOD.
ENDCLASS.

CLASS lcl_percentage_discount DEFINITION.
  PUBLIC SECTION.
    INTERFACES lif_discount_strategy.
    METHODS: constructor IMPORTING iv_percent TYPE p.
  PRIVATE SECTION.
    DATA: mv_percent TYPE p.
ENDCLASS.
CLASS lcl_percentage_discount IMPLEMENTATION.
  METHOD constructor.
    mv_percent = iv_percent.
  ENDMETHOD.
  METHOD lif_discount_strategy~calculate.
    rv_final = iv_price * ( 1 - mv_percent / 100 ).
  ENDMETHOD.
ENDCLASS.

CLASS lcl_shopping_cart DEFINITION.
  PUBLIC SECTION.
    METHODS: set_strategy IMPORTING io_strategy TYPE REF TO lif_discount_strategy,
             checkout     IMPORTING iv_price TYPE p RETURNING VALUE(rv_final) TYPE p.
  PRIVATE SECTION.
    DATA: mo_strategy TYPE REF TO lif_discount_strategy.
ENDCLASS.
CLASS lcl_shopping_cart IMPLEMENTATION.
  METHOD set_strategy.
    mo_strategy = io_strategy.
  ENDMETHOD.
  METHOD checkout.
    rv_final = mo_strategy->calculate( iv_price ).
  ENDMETHOD.
ENDCLASS.

6.3 观察者模式(Observer Pattern)

INTERFACE lif_observer.
  METHODS: on_update IMPORTING iv_data TYPE string.
ENDINTERFACE.

CLASS lcl_subject DEFINITION.
  PUBLIC SECTION.
    METHODS: attach IMPORTING io_observer TYPE REF TO lif_observer,
             detach IMPORTING io_observer TYPE REF TO lif_observer,
             notify IMPORTING iv_data TYPE string.
  PRIVATE SECTION.
    DATA: mt_observers TYPE TABLE OF REF TO lif_observer.
ENDCLASS.

CLASS lcl_subject IMPLEMENTATION.
  METHOD attach.
    APPEND io_observer TO mt_observers.
  ENDMETHOD.
  METHOD detach.
    DELETE mt_observers WHERE table_line = io_observer.
  ENDMETHOD.
  METHOD notify.
    LOOP AT mt_observers INTO DATA(lo_obs).
      lo_obs->on_update( iv_data ).
    ENDLOOP.
  ENDMETHOD.
ENDCLASS.

---

七、ABAP Unit 测试

7.1 编写测试类

CLASS lcl_calculator DEFINITION.
  PUBLIC SECTION.
    METHODS: add IMPORTING iv_a TYPE i iv_b TYPE i RETURNING VALUE(rv_result) TYPE i,
             divide IMPORTING iv_a TYPE i iv_b TYPE i RETURNING VALUE(rv_result) TYPE p
                    RAISING cx_sy_zerodivide.
ENDCLASS.

CLASS lcl_calculator IMPLEMENTATION.
  METHOD add.
    rv_result = iv_a + iv_b.
  ENDMETHOD.
  METHOD divide.
    IF iv_b = 0.
      RAISE EXCEPTION TYPE cx_sy_zerodivide.
    ENDIF.
    rv_result = iv_a / iv_b.
  ENDMETHOD.
ENDCLASS.

* 测试类
CLASS ltc_calculator DEFINITION FOR TESTING
  DURATION SHORT RISK LEVEL HARMLESS.
  PRIVATE SECTION.
    DATA: mo_cut TYPE REF TO lcl_calculator.  " Class Under Test
    METHODS: setup,
             test_add FOR TESTING,
             test_divide FOR TESTING,
             test_divide_by_zero FOR TESTING.
ENDCLASS.

CLASS ltc_calculator IMPLEMENTATION.
  METHOD setup.
    mo_cut = NEW lcl_calculator( ).
  ENDMETHOD.
  METHOD test_add.
    cl_abap_unit_assert=>assert_equals(
      act = mo_cut->add( iv_a = 2 iv_b = 3 )
      exp = 5
      msg = 'Addition should return 5' ).
  ENDMETHOD.
  METHOD test_divide.
    cl_abap_unit_assert=>assert_equals(
      act = mo_cut->divide( iv_a = 10 iv_b = 2 )
      exp = 5
      msg = 'Division should return 5' ).
  ENDMETHOD.
  METHOD test_divide_by_zero.
    TRY.
        mo_cut->divide( iv_a = 10 iv_b = 0 ).
        cl_abap_unit_assert=>fail( 'Should have raised cx_sy_zerodivide' ).
      CATCH cx_sy_zerodivide.
        " Expected
    ENDTRY.
  ENDMETHOD.
ENDCLASS.

7.2 测试断言方法

* 常用断言
cl_abap_unit_assert=>assert_equals( act = lv_act exp = lv_exp ).
cl_abap_unit_assert=>assert_differs( act = lv_act exp = lv_exp ).
cl_abap_unit_assert=>assert_initial( act = lv_value ).
cl_abap_unit_assert=>assert_not_initial( act = lv_value ).
cl_abap_unit_assert=>assert_true( act = lv_bool ).
cl_abap_unit_assert=>assert_false( act = lv_bool ).
cl_abap_unit_assert=>assert_number_between( lower = 1 upper = 100 number = lv_num ).

---

八、BAdI 与增强框架

8.1 经典 BAdI

* 定义 BAdI (SE19)
INTERFACE lif_custom_logic.
  METHODS: execute IMPORTING iv_input TYPE string
                   RETURNING VALUE(rv_output) TYPE string.
ENDINTERFACE.

* BAdI 实现
CLASS lcl_custom_impl DEFINITION.
  PUBLIC SECTION.
    INTERFACES lif_custom_logic.
ENDCLASS.

CLASS lcl_custom_impl IMPLEMENTATION.
  METHOD lif_custom_logic~execute.
    rv_output = |Processed: { iv_input }|.
  ENDMETHOD.
ENDCLASS.

* 调用 BAdI
DATA: lo_badi TYPE REF TO lif_custom_logic.
GET BADI lo_badi.
CALL BADI lo_badi->execute
  EXPORTING iv_input = 'Test'
  RECEIVING rv_output = DATA(lv_result).

8.2 新式 BAdI (Enhancement Spot)

* 使用增强点
DATA: lo_badi TYPE REF TO if_custom_logic.

TRY.
    GET BADI lo_badi.
    CALL BADI lo_badi->execute
      EXPORTING iv_input = 'Data'
      RECEIVING rv_output = DATA(lv_output).
  CATCH cx_badi_not_implemented.
    " 无实现时的默认处理
ENDTRY.

---

九、与现代ABAP框架集成

9.1 CDS View 实体

* 定义 CDS View
@AbapCatalog.sqlViewName: 'ZSALESV'
@AbapCatalog.compiler.compareFilter: true
@AccessControl.authorizationCheck: #CHECK
@EndUserText.label: 'Sales Order View'
define view Z_SALES_ORDER
  as select from vbak
{
  key vbeln      as OrderNumber,
      erdat      as CreatedOn,
      ernam      as CreatedBy,
      netwr      as NetValue,
      waerk      as Currency
}
where netwr > 0;

9.2 RAP (RESTful ABAP Programming)

* Behavior Definition
managed implementation in class zbp_sales_order unique;

define behavior for Z_SALES_ORDER alias SalesOrder
{
  create;
  update;
  delete;
  validation check_amount on save { field NetValue; }
  action set_status parameter Z_STATUS_PARAM result [1] $result;
}

* Behavior Implementation
CLASS zbp_sales_order DEFINITION PUBLIC ABSTRACT FINAL FOR BEHAVIOR OF Z_SALES_ORDER.
ENDCLASS.

CLASS zbp_sales_order IMPLEMENTATION.
ENDCLASS.

---

十、最佳实践总结

10.1 SOLID 原则在 ABAP 中的应用

原则	含义	ABAP 实践
S - 单一职责	一个类只做一件事	业务类与数据访问类分离
O - 开闭原则	对扩展开放,对修改关闭	使用接口+BAdI扩展
L - 里氏替换	子类可替换父类	避免重写改变方法语义
I - 接口隔离	接口应小而专	拆分大接口为多个小接口
D - 依赖倒置	依赖抽象而非具体	通过接口引用而非具体类

10.2 编码规范

1. 命名约定

   • 类: lcl_xxx (本地) / zcl_xxx (全局)
   • 接口: lif_xxx (本地) / zif_xxx (全局)
   • 方法: get_xxx / set_xxx / is_xxx (返回布尔)
   • 属性: mv_xxx (实例) / gv_xxx (全局静态)

2. 构造方法

   • 参数不超过 5 个,过多时使用结构体
   • 必要参数放 constructor,可选参数用 setter

3. 错误处理

   • 使用异常类(cx_xxx)而非返回码
   • 异常应携带有意义的消息

4. 测试覆盖

   • 每个公共方法至少一个测试用例
   • 边界条件和异常路径必须测试

---

学习资源推荐

1. SAP 官方文档: help.sap.com → ABAP Objects
2. SAP Press:《ABAP Objects: ABAP Object-Oriented Programming》
3. openSAP 课程: “Writing Testable ABAP Code”、”ABAP Development for SAP HANA”
4. 实践建议: 从改造传统 ABAP 程序开始,逐步引入类和接口
5. 社区: SAP Community Network (SCN) 的 ABAP 板块