Secondary Indexes

Secondary indexes 用于启用基于原始 Redis 结构的查找操作。每次保存时，都会将值写入相应的索引，并且在删除或 expire 对象后都会将其移除。

Secondary indexes are used to enable lookup operations based on native Redis structures. Values are written to the according indexes on every save and are removed when objects are deleted or expire.

Simple Property Index

给定前面显示的示例 Person 实体，我们可以通过用 @Indexed 注释该属性为 firstname 创建一个索引，如下面的示例所示：

Given the sample Person entity shown earlier, we can create an index for firstname by annotating the property with @Indexed, as shown in the following example:

Example 1. Annotation driven indexing

@RedisHash("people")
public class Person {

  @Id String id;
  @Indexed String firstname;
  String lastname;
  Address address;
}

索引针对实际属性值建立。保存两个人（例如，“rand”和“aviendha”）将导致建立类似于以下内容的索引：

Indexes are built up for actual property values. Saving two Persons (for example, "rand" and "aviendha") results in setting up indexes similar to the following:

SADD people:firstname:rand e2c7dcee-b8cd-4424-883e-736ce564363e
SADD people:firstname:aviendha a9d4b3a0-50d3-4538-a2fc-f7fc2581ee56

还可以对嵌套元素建立索引。假设 Address 有一个用 @Indexed 注释的 city 属性。在这种情况下，只要 person.address.city 不为 null，我们就会为每个城市拥有集合，如下面的示例所示：

It is also possible to have indexes on nested elements. Assume Address has a city property that is annotated with @Indexed. In that case, once person.address.city is not null, we have Sets for each city, as shown in the following example:

SADD people:address.city:tear e2c7dcee-b8cd-4424-883e-736ce564363e

此外，通过编程设置，你可以定义对映射键和列表属性的索引，如下面的示例所示：

Furthermore, the programmatic setup lets you define indexes on map keys and list properties, as shown in the following example:

@RedisHash("people")
public class Person {

  // ... other properties omitted

  Map<String, String> attributes;     1
  Map<String, Person> relatives;      2
  List<Address> addresses;            3
}

1	`SADD people:attributes.map-key:map-value e2c7dcee-b8cd-4424-883e-736ce564363e`
2	`SADD people:relatives.map-key.firstname:tam e2c7dcee-b8cd-4424-883e-736ce564363e`
3	`SADD people:addresses.city:tear e2c7dcee-b8cd-4424-883e-736ce564363e`

无法在“ References”上解析索引。

Indexes cannot be resolved on References.

与键空间一样，你可以配置索引，而不必注释实际域类型，如下面的示例所示：

As with keyspaces, you can configure indexes without needing to annotate the actual domain type, as shown in the following example:

Example 2. Index Setup with @EnableRedisRepositories

@Configuration
@EnableRedisRepositories(indexConfiguration = MyIndexConfiguration.class)
public class ApplicationConfig {

  //... RedisConnectionFactory and RedisTemplate Bean definitions omitted

  public static class MyIndexConfiguration extends IndexConfiguration {

    @Override
    protected Iterable<IndexDefinition> initialConfiguration() {
      return Collections.singleton(new SimpleIndexDefinition("people", "firstname"));
    }
  }
}

同样，与键空间一样，你可以通过编程配置索引，如下面的示例所示：

Again, as with keyspaces, you can programmatically configure indexes, as shown in the following example:

Example 3. Programmatic Index setup

@Configuration
@EnableRedisRepositories
public class ApplicationConfig {

  //... RedisConnectionFactory and RedisTemplate Bean definitions omitted

  @Bean
  public RedisMappingContext keyValueMappingContext() {
    return new RedisMappingContext(
      new MappingConfiguration(
        new KeyspaceConfiguration(), new MyIndexConfiguration()));
  }

  public static class MyIndexConfiguration extends IndexConfiguration {

    @Override
    protected Iterable<IndexDefinition> initialConfiguration() {
      return Collections.singleton(new SimpleIndexDefinition("people", "firstname"));
    }
  }
}

Geospatial Index

假设 Address 类型包含一个 location 属性，该属性属于 Point 类型，并且保存特定地址的地理坐标。通过用 @GeoIndexed 注释该属性，Spring Data Redis 会使用 Redis GEO 命令添加这些值，如下面的示例所示：

Assume the Address type contains a location property of type Point that holds the geo coordinates of the particular address. By annotating the property with @GeoIndexed, Spring Data Redis adds those values by using Redis GEO commands, as shown in the following example:

@RedisHash("people")
public class Person {

  Address address;

  // ... other properties omitted
}

public class Address {

  @GeoIndexed Point location;

  // ... other properties omitted
}

public interface PersonRepository extends CrudRepository<Person, String> {

  List<Person> findByAddressLocationNear(Point point, Distance distance);     1
  List<Person> findByAddressLocationWithin(Circle circle);                    2
}

Person rand = new Person("rand", "al'thor");
rand.setAddress(new Address(new Point(13.361389D, 38.115556D)));

repository.save(rand);                                                        3

repository.findByAddressLocationNear(new Point(15D, 37D), new Distance(200, Metrics.KILOMETERS)); 4

1	Query method declaration on a nested property, using `Point` and `Distance`.
2	Query method declaration on a nested property, using `Circle` to search within.
3	`GEOADD people:address:location 13.361389 38.115556 e2c7dcee-b8cd-4424-883e-736ce564363e`
4	`GEORADIUS people:address:location 15.0 37.0 200.0 km`

在前一个示例中，使用将对象的 id 作为成员名称的 GEOADD 存储经度和纬度值。查找器方法允许使用 Circle 或 Point, Distance 组合来查询那些值。

In the preceding example the, longitude and latitude values are stored by using GEOADD that use the object’s id as the member’s name. The finder methods allow usage of Circle or Point, Distance combinations for querying those values.

not 可以将 near 和 within 与其他条件相结合。

It is not possible to combine near and within with other criteria.