android - @IntDef Android 支持带有 Jackson 反序列化的注释

Question

将 JacksonAnnotations 与 Android 支持注释一起使用。我的 POJO 是:

@JsonIgnoreProperties(ignoreUnknown = true)
public class Schedule {
    public static final int SUNDAY = 0;
    public static final int MONDAY = 1;
    public static final int TUESDAY = 2;
    public static final int WEDNESDAY = 3;
    public static final int THURSDAY = 4;
    public static final int FRIDAY = 5;
    public static final int SATURDAY = 6;

    private Integer weekday;

    public Schedule() {
    }

    @Weekday
    public Integer getWeekday() {
        return weekday;
    }

    public void setWeekday(@Weekday Integer weekday) {
        this.weekday = weekday;
    }

    @Retention(RetentionPolicy.RUNTIME)
    @IntDef({SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY})
    public @interface Weekday {}
}

从支持我得到对象:

{"schedule":{"weekday":"MONDAY"}}

我想要的是将 Weekday 映射到常量中定义的整数值。有什么办法可以做到这一点？

更新:主要目的是优化(你应该严格避免在Android上使用枚举就像它所说的here)。

Answer 1

由于您可以指望工作日不会失控，因此创建静态 map 似乎是一个非常干净的解决方案。提供一个名为 fromString 的 @JsonCreator 工厂可以与 Jackson 一起使用，也可以 play nicely with JAX-RS :

public class Schedule {
    ...
    private static final ImmutableMap<String, Schedule> WEEKDAY_TO_INT_MAP =
            ImmutableMap.<String, Schedule>builder()
                .put("SUNDAY", withIntWeekday(0))
                .put("MONDAY", withIntWeekday(1))
                .put("TUESDAY", withIntWeekday(2))
                .put("WEDNESDAY", withIntWeekday(3))
                .put("THURSDAY", withIntWeekday(4))
                .put("FRIDAY", withIntWeekday(5))
                .put("SATURDAY", withIntWeekday(6))
                .build();

    public static Schedule withIntWeekday(int weekdayInt) {
        Schedule schedule = new Schedule();
        schedule.setWeekday(weekdayInt);
        return schedule;
    }

    @JsonCreator
    public static Schedule fromString(String weekday) {
        return WEEKDAY_TO_INT_MAP.get(weekday);
    }
    ...
}