MyBatis中实现数据封装的示例代码

@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface Results {
  /**
   * Returns the id of this result map.
   *
   * @return the id of this result map
   */
  String id() default "";//这个结果映射集的名字

  /**
   * Returns mapping definitions for property.
   *
   * @return mapping definitions
   */
  Result[] value() default {};//Result类型数组
}

@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@Repeatable(Results.class)
public @interface Result {
  /**
   * Returns whether id column or not.
   *
   * @return {@code true} if id column; {@code false} if otherwise
   */
  boolean id() default false;//通过true/false表示当前列是否为主键

  /**
   * Return the column name(or column label) to map to this argument.
   *
   * @return the column name(or column label)
   */
  String column() default "";//指定表中要映射字段名

  /**
   * Returns the property name for applying this mapping.
   *
   * @return the property name
   */
  String property() default "";//指定类中要被映射的属性名
}

@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface ResultMap {
  /**
   * Returns result map names to use.
   *
   * @return result map names
   */
  String[] value();//映射关系名
}

# 配置Mybatis的驼峰命名自动转换，使数据库表中字段名和实体类属性间实现蛇形命名和驼峰命名的自动映射
mybatis.configuration.map-underscore-to-camel-case=true