[英]How can I store nested Hashmap in Redis?
I want to store netsted HashMap
in Redis
having single key.我想将 netsted
HashMap
存储在具有单个键的Redis
中。
For example :例如 :
HashMap<String, HashMap<String,String>> map = new HashMap<>();
Please Suggest :请建议:
Redis doesn't support it as of now. Redis 目前不支持它。 However there is a way to do it, other than
rejson
.但是,除了
rejson
,还有一种方法可以做到这rejson
。
You can convert it into JSON and store in Redis and retrieve.您可以将其转换为 JSON 并存储在 Redis 中并检索。 Following utility methods, which I use in Jackson.
遵循我在 Jackson 中使用的实用方法。
To convert Object to String :将 Object 转换为 String :
public static String stringify(Object object) {
ObjectMapper jackson = new ObjectMapper();
jackson.setSerializationInclusion(JsonSerialize.Inclusion.NON_NULL);
try {
return jackson.writeValueAsString(object);
} catch (Exception ex) {
LOG.log(Level.SEVERE, "Error while creating json: ", ex);
}
return null;
}
Example : stringify(obj);
示例:
stringify(obj);
To convert String to Object :将 String 转换为 Object :
public static <T> T objectify(String content, TypeReference valueType) {
try {
ObjectMapper mapper = new ObjectMapper();
mapper.configure(Feature.WRITE_DATES_AS_TIMESTAMPS, false);
DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss.SSS");
dateFormat.setTimeZone(Calendar.getInstance().getTimeZone());
mapper.setDateFormat(dateFormat);
return mapper.readValue(content, valueType);
} catch (Exception e) {
LOG.log(Level.WARNING, "returning null because of error : {0}", e.getMessage());
return null;
}
}
Example : List<Object> list = objectify("Your Json", new TypeReference<List<Object>>(){})
示例:
List<Object> list = objectify("Your Json", new TypeReference<List<Object>>(){})
You can update this method as per your requirement.您可以根据需要更新此方法。 I am sure, you know, how to add and update in Redis.
我确定,您知道如何在 Redis 中添加和更新。
Redis doesn't support storing hash inside hash. Redis 不支持在哈希中存储哈希。 But there is REDIS as a JSON store that can store JSON in REDIS, It allows storing, updating and fetching JSON values from Redis keys.
但是有REDIS 作为 JSON 存储,可以在 REDIS 中存储 JSON,它允许从 Redis 键存储、更新和获取 JSON 值。 I think this can help you to store your data.
我认为这可以帮助您存储数据。
REDIS now allows nested HashMap https://redis.io/topics/data-types REDIS 现在允许嵌套 HashMap https://redis.io/topics/data-types
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
<version>1.5.22.RELEASE</version>
</dependency>
public class Redis {
@Autowired
RedisService redisService;
@Cacheable(value = "name", key = "keyvalue")
public Map<String, HashMap<String, String>> redisNestedMap(String keyvalue) {
return redisService.getNestedMap();
}
}
@Component
public class RedisService {
public Map<String, HashMap<String, String>> getNestedMap() {
Map<String, HashMap<String, String>> nestedMap = new HashMap<>();
HashMap<String, String> value = new HashMap<>();
value.put("key", "value");
nestedMap.put("one", value);
return nestedMap;
}
}
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