6

使用 CassandraReporitory 的 findOne() 或 findAll() 方法时出现以下异常：

Caused by: java.lang.IllegalStateException: property does not have a single column mapping
    at org.springframework.data.cassandra.mapping.BasicCassandraPersistentProperty.getColumnName(BasicCassandraPersistentProperty.java:134)
    at org.springframework.data.cassandra.convert.BasicCassandraRowValueProvider.getPropertyValue(BasicCassandraRowValueProvider.java:64)
    at org.springframework.data.cassandra.convert.BasicCassandraRowValueProvider.getPropertyValue(BasicCassandraRowValueProvider.java:35)
    at org.springframework.data.mapping.model.PersistentEntityParameterValueProvider.getParameterValue(PersistentEntityParameterValueProvider.java:78)
    at org.springframework.data.convert.ReflectionEntityInstantiator.createInstance(ReflectionEntityInstantiator.java:71)
    at org.springframework.data.convert.ClassGeneratingEntityInstantiator.createInstance(ClassGeneratingEntityInstantiator.java:83)
    at org.springframework.data.cassandra.convert.MappingCassandraConverter.readEntityFromRow(MappingCassandraConverter.java:133)
    at org.springframework.data.cassandra.convert.MappingCassandraConverter.readRow(MappingCassandraConverter.java:115)
    at org.springframework.data.cassandra.convert.MappingCassandraConverter.read(MappingCassandraConverter.java:200)
    at org.springframework.data.cassandra.repository.query.AbstractCassandraQuery.getSingleEntity(AbstractCassandraQuery.java:176)
    at org.springframework.data.cassandra.repository.query.AbstractCassandraQuery.execute(AbstractCassandraQuery.java:133)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:454)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:432)

我的类定义如下：

@PrimaryKeyClass
public class ItemAndLocationKey implements Serializable {

    private static final long serialVersionUID = 1L;

    @PrimaryKeyColumn(name = "itemId", ordinal = 0, type = PrimaryKeyType.PARTITIONED)
    @CassandraType(type = Name.UUID)
    private UUID itemId;
    @PrimaryKeyColumn(name = "locationId", ordinal = 1, type = PrimaryKeyType.CLUSTERED)
    @CassandraType(type = Name.UUID)
    private UUID locationId;

    public ItemAndLocationKey(UUID itemId, UUID locationId) {
        this.itemId = itemId;
        this.locationId = locationId;
    }

    public UUID getItemId() {
        return itemId;
    }

    public void setItemId(UUID itemId) {
        this.itemId = itemId;
    }

    public UUID getLocationId() {
        return locationId;
    }

    public void setLocationId(UUID locationId) {
        this.locationId = locationId;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        ItemAndLocationKey that = (ItemAndLocationKey) o;

        if (!itemId.equals(that.itemId)) return false;
        return locationId.equals(that.locationId);
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + itemId.hashCode();
        result = prime * result + locationId.hashCode();
        return result;
    }
}

@Table(value = ItemAndLocation.tableName)
public class ItemAndLocation {

    @org.springframework.data.annotation.Transient
    public static final String tableName = "ItemAndLocation";

    @PrimaryKey
    private ItemAndLocationKey itemAndLocationKey;

    public ItemAndLocation(ItemAndLocationKey itemAndLocationKey) {
        this.itemAndLocationKey = itemAndLocationKey;
    }

    public ItemAndLocationKey getItemAndLocationKey() {
        return itemAndLocationKey;
    }

    public void setItemAndLocationKey(ItemAndLocationKey itemAndLocationKey) {
        this.itemAndLocationKey = itemAndLocationKey;
    }
}

public interface ItemAndLocationRepository extends TypedIdCassandraRepository<ItemAndLocation, ItemAndLocationKey> {

}

本质上，这里发生的是，在调用 findOne() 或 findAll() 期间从 Cassandra 读取一行后，spring data cassandra 尝试使用 ClassGeneratingEntityInstantiator 实例化不知道如何填充复合主键对象的 ItemAndLocation 对象，项目和位置键。我不知道如何提供自定义对象实例化器。当前版本没有示例或文档。

任何帮助都感激不尽。

4

2 回答 2

6

我遇到了同样的问题，问题出在用 @Table 注释的类中。

在您的场景中，您必须删除以下类中的重载构造函数：

@Table(value = ItemAndLocation.tableName)
public class ItemAndLocation {

    @org.springframework.data.annotation.Transient
    public static final String tableName = "ItemAndLocation";

    @PrimaryKey
    private ItemAndLocationKey itemAndLocationKey;

    // \\\\\\\\\\\\\\\\\\\\ REMOVE THIS CONSTRUCTOR //////////////////
    // public ItemAndLocation(ItemAndLocationKey itemAndLocationKey) {
    //    this.itemAndLocationKey = itemAndLocationKey;
    // }
    // ////////////////////////////////\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\


    public ItemAndLocationKey getItemAndLocationKey() {
        return itemAndLocationKey;
    }

    public void setItemAndLocationKey(ItemAndLocationKey itemAndLocationKey) {
        this.itemAndLocationKey = itemAndLocationKey;
   }
}

我希望这有帮助 ：）

于 2016-02-10T09:47:49.463 回答
4

我在 Main 实体类和PrimaryKey-class 中都遇到了同样的问题。为我解决的问题是提供不带参数的默认构造函数并将所有字段初始化为某个默认值，这意味着null对于Objects、false对于booleans 和0所有其他原始类型。

在您的情况下，这意味着添加：

private ItemAndLocation() {
    this.itemAndLocationKey = null;
}

和

private ItemAndLocationKey() {
    this.itemId = null;
    this.locationId = null;
}

构造函数不需要，字段public可以final，框架将通过反射设置值。

于 2016-07-15T10:46:50.370 回答