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之前写了JAVA操作cassandra驱动包，现在来看看spring-data对cassandra的支持。这里是spring-data-cassandra的官方文档：docs.spring.io/spring-data… 这个目录下还有api、版本日志等：docs.spring.io/spring-data…
- 引入jar包
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-cassandra</artifactId>
<version>1.5.0.M1</version>
</dependency>
- 定义bean
import org.springframework.data.cassandra.mapping.Column;
import org.springframework.data.cassandra.mapping.PrimaryKey;
import org.springframework.data.cassandra.mapping.Table;
@Table
public class Person
{
// 主键
@PrimaryKey
private String id;
// 列名 与数据库列名一致时可不加
@Column(value = "name")
private String name;
private int age;
// 支持构造函数
public Person(String id, String name, int age)
{
this.id = id;
this.name = name;
this.age = age;
}
public String getId()
{
return id;
}
public void setId(String id)
{
this.id = id;
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public int getAge()
{
return age;
}
public void setAge(int age)
{
this.age = age;
}
@Override
public String toString()
{
return "Person [id=" + id + ", name=" + name + ", age=" + age + "]";
}
}
- 对应的CQL建表语句
CREATE TABLE mydb.person (
id text PRIMARY KEY,
age int,
name text
)
可以看出和JPA的注解很类似，不同的是cassandra主键用的是@PrimaryKey，而且允许使用构造函数。如果存在复合主键，则要先映射一个主键的实体类，再映射一个包含这个主键的实体类。
例如：
import org.springframework.cassandra.core.Ordering;
import org.springframework.cassandra.core.PrimaryKeyType;
import org.springframework.data.cassandra.mapping.PrimaryKeyClass;
import org.springframework.data.cassandra.mapping.PrimaryKeyColumn;
@PrimaryKeyClass
public class Person2Key
{
// 分区键
@PrimaryKeyColumn(name = "id", ordinal = 0, type = PrimaryKeyType.PARTITIONED)
private String id;
// 集群键
@PrimaryKeyColumn(name = "name", ordinal = 1, type = PrimaryKeyType.CLUSTERED, ordering = Ordering.DESCENDING)
private String name;
public String getId()
{
return id;
}
public void setId(String id)
{
this.id = id;
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
@Override
public String toString()
{
return "Person2Key [id=" + id + ", name=" + name + "]";
}
}
import org.springframework.data.cassandra.mapping.PrimaryKey;
import org.springframework.data.cassandra.mapping.Table;
@Table(value = "person2")
public class Person2
{
@PrimaryKey
private Person2Key pKey;
private int age;
public Person2Key getpKey()
{
return pKey;
}
public void setpKey(Person2Key pKey)
{
this.pKey = pKey;
}
public int getAge()
{
return age;
}
public void setAge(int age)
{
this.age = age;
}
@Override
public String toString()
{
return "Person2 [pKey=" + pKey + ", age=" + age + "]";
}
}
对应的CQL建表语句
CREATE TABLE mydb.person2 (
id text,
name text,
age int,
PRIMARY KEY (id, name)
) WITH CLUSTERING ORDER BY (name DESC)
其中的WITH CLUSTERING ORDER BY (name DESC) 对应主键类里的ordering = Ordering.DESCENDING，按照name降序存储，只有集群键才能在建表时设置降序存储。
- 定义spring-data接口
import java.util.List;
import org.springframework.data.cassandra.repository.Query;
import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;
import com.my.domin.pojo.Person2;
@Repository
public interface PersonRepository extends CrudRepository<Person2, String>
{
@Query("select * from Person2 where id= ?1 and name= ?2")
List<Person2> findByIdAndName(String id, String name);
}
这里面实现了一组CURD方法，如果要写一些条件查询的话可以参考
@Query("select * from Person where id= ?1 and name= ?2 ALLOW FILTERING")
List<Person> findByIdAndName(String id, String name);
spring-data-cassandra文档里还提到一个分页的仓库接口类PagingAndSortingRepository，这个继承自CrudRepository，而且提供了2个分页方法。
- 测试方法：
import java.util.Iterator;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.cassandra.core.CassandraOperations;
import org.springframework.stereotype.Service;
import com.datastax.driver.core.querybuilder.QueryBuilder;
import com.datastax.driver.core.querybuilder.Select;
import com.my.domin.pojo.Person;
import com.my.repository.PersonRepository;
import com.my.service.PersonService;
@Service
public class PersonServiceImpl implements PersonService
{
@Autowired
private PersonRepository personRepository;
@Autowired
private CassandraOperations cassandraOperations;
@Override
public void test()
{
//通过Repository查询
Iterable<Person> iterable = personRepository.findAll();
Iterator<Person> it = iterable.iterator();
System.out.println("==>findAll:");
while (it.hasNext())
{
Person p = it.next();
System.out.println(p.toString());
}
//通过Repository 自定义查询查询
List<Person> list = personRepository.findByIdAndName("1", "one");
System.out.println("==>findByIdAndName:");
for (Person person : list)
{
System.out.println(person.toString());
}
//通过cassandraOperations查询
Select select = QueryBuilder.select().from("person");
select.where(QueryBuilder.eq("id", "1"));
Person person = cassandraOperations.selectOne(select, Person.class);
System.out.println("==>cassandraOperations:");
System.out.println(person.toString());
}
}
-
输出结果
