Question

我从Joda Time为LocalTime课程编写了一个自定义容器：

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，我得到以下异常：

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

哦，天哪，我很笨。答案就是隐藏在异常中：

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

我正在返回的javaToSqlArg方法

((LocalTime) javaObject).millisOfDay()

当我应该回来时

((LocalTime) javaObject).getMillisOfDay()

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

为什么我的ORMLite自定义持久性不能在Android上运行？

1 个答案: