java - 为什么我的 ORMLite 自定义持久化器不能在 Android 上运行？

Question

我为来自 Joda Time 的 LocalTime 类编写了一个自定义持久化器:

public class LocalTimePersister extends BaseDataType {

    private static final LocalTimePersister instance = new LocalTimePersister();

    private LocalTimePersister() {
        super(SqlType.LONG, new Class<?>[] { LocalTime.class });
    }

    public static LocalTimePersister getSingleton() {
        return instance;
    }

    @Override
    public Object javaToSqlArg(FieldType fieldType, Object javaObject) {
        if (javaObject == null) {
            return null;
        } else {
            return ((LocalTime) javaObject).millisOfDay();
        }
    }

    @Override
    public Object resultToSqlArg(FieldType fieldType, DatabaseResults results, int columnPos) throws SQLException {
        return results.getLong(columnPos);
    }

    @Override
    public Object parseDefaultString(FieldType fieldType, String defaultStr) throws SQLException {
        return Long.parseLong(defaultStr);
    }

    @Override
    public Object sqlArgToJava(FieldType fieldType, Object sqlArg, int columnPos) throws SQLException {
        Long millis = (Long)sqlArg;
        if (millis == null) {
            return null;
        } else {
            return LocalTime.fromMillisOfDay(millis);
        }
    }
}

具有 LocalTime 成员的类声明如下:

@DatabaseField(canBeNull = false, persisterClass = LocalTimePersister.class)
private LocalTime time;

我已经重新生成了我的数据库配置文件:

# --field-start--
fieldName=time
canBeNull=false
persisterClass=com.myapp.db.persisters.LocalTimePersister
# --field-end--

当我尝试创建一个具有 LocalTime 字段的对象并将其添加到数据库时，出现以下异常:

java.lang.ClassCastException: org.joda.time.LocalTime$Property cannot be cast to java.lang.Number
        at com.j256.ormlite.android.AndroidDatabaseConnection.bindArgs(AndroidDatabaseConnection.java:345)
        at com.j256.ormlite.android.AndroidDatabaseConnection.insert(AndroidDatabaseConnection.java:156)
        at com.j256.ormlite.stmt.mapped.MappedCreate.insert(MappedCreate.java:91)
        at com.j256.ormlite.stmt.StatementExecutor.create(StatementExecutor.java:450)
        at com.j256.ormlite.dao.BaseDaoImpl.create(BaseDaoImpl.java:310)
        at com.myapp.db.DBHandler.populateDB(DBHandler.java:178)

Answer 1

天哪，我太笨了。答案就隐藏在异常中:

org.joda.time.LocalTime$Property cannot be cast to java.lang.Number

在我要返回的javaToSqlArg 方法中

((LocalTime) javaObject).millisOfDay()

什么时候回来

((LocalTime) javaObject).getMillisOfDay()

millisOfDay() 返回一个 LocalTime.Property，getMillisOfDay() 返回一个 int。