Question

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)

我的课程定义如下：

@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> {

}

本质上发生的事情是，在调用findOne（）或findAll（）期间从Cassandra读取一行后，spring数据cassandra尝试使用ClassGeneratingEntityInstantiator来实例化不知道如何填充复合主要的ItemAndLocation对象key对象，ItemAndLocationKey。我无法弄清楚如何提供自定义对象实例化器。当前版本没有示例或文档。

非常感谢任何帮助。

Answer 1

我遇到了同样的问题，问题出在使用@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; } }

我希望这会有所帮助：）

Answer 2

我在Main实体类和PrimaryKey - 类中都遇到了同样的问题。为我修复的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些默认值，这意味着null为Object，false为所有其他原始类型的boolean和0。

在你的情况下意味着添加：

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

和

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

构造函数不需要public，字段可以是final，框架将通过反射设置值。

使用Spring-data-cassandra查询具有复合主键的表

2 个答案: