vc:${list_id}
的哈希。我已经成功地将其插入到Redis中。然而,当我使用redis-cli检查键时,我没有看到键vc:501381
。相反,我看到了\xac\xed\x00\x05t\x00\tvc:501381
。这是为什么,并且我该如何更改它?
vc:${list_id}
的哈希。我已经成功地将其插入到Redis中。然而,当我使用redis-cli检查键时,我没有看到键vc:501381
。相反,我看到了\xac\xed\x00\x05t\x00\tvc:501381
。好的,我在Google上搜索了一段时间,并在 http://java.dzone.com/articles/spring-data-redis 找到了帮助。
这是因为Java序列化导致的。
redisTemplate的键序列化器需要配置为StringRedisSerializer
,如下所示:
<bean
id="jedisConnectionFactory"
class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"
p:host-name="${redis.server}"
p:port="${redis.port}"
p:use-pool="true"/>
<bean
id="stringRedisSerializer"
class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
<bean
id="redisTemplate"
class="org.springframework.data.redis.core.RedisTemplate"
p:connection-factory-ref="jedisConnectionFactory"
p:keySerializer-ref="stringRedisSerializer"
p:hashKeySerializer-ref="stringRedisSerializer"
/>
现在redis中的键是vc:501381
。
或者像@niconic说的那样,我们也可以将默认的序列化器设置为字符串序列化器,如下所示:
<bean
id="redisTemplate"
class="org.springframework.data.redis.core.RedisTemplate"
p:connection-factory-ref="jedisConnectionFactory"
p:defaultSerializer-ref="stringRedisSerializer"
/>
这意味着我们所有的键和值都是字符串。但请注意,这可能并不理想,因为您可能希望您的值不仅仅是字符串。
如果您的值是一个域对象,那么您可以使用Jackson序列化器,并像这里提到的那样配置一个序列化器:
<bean id="userJsonRedisSerializer" class="org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer">
<constructor-arg type="java.lang.Class" value="com.mycompany.redis.domain.User"/>
</bean>
并配置您的模板为:
<bean
id="redisTemplate"
class="org.springframework.data.redis.core.RedisTemplate"
p:connection-factory-ref="jedisConnectionFactory"
p:keySerializer-ref="stringRedisSerializer"
p:hashKeySerializer-ref="stringRedisSerializer"
p:valueSerialier-ref="userJsonRedisSerializer"
/>
这是一个非常古老的问题,但我的答案可能对那些在使用Spring Boot使用Redis时遇到相同问题的人有所帮助。当我在Redis中存储哈希类型数据时,遇到了相同的问题。我已经编写了所需的配置文件更改来适用于RedisTemplate。
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
@Configuration
@ComponentScan(basePackages = "com.redis")
public class AppCofiguration {
@Bean
JedisConnectionFactory jedisConnectionFactory() {
JedisConnectionFactory jedisConFactory = new JedisConnectionFactory();
jedisConFactory.setHostName("127.0.0.1");
jedisConFactory.setPort(6379);
return jedisConFactory;
}
@Bean
public RedisTemplate<String, Object> redisTemplate() {
final RedisTemplate<String, Object> template = new RedisTemplate<String, Object>();
template.setConnectionFactory(jedisConnectionFactory());
template.setKeySerializer(new StringRedisSerializer());
template.setValueSerializer(new StringRedisSerializer());
// the following is not required
template.setHashValueSerializer(new StringRedisSerializer());
template.setHashKeySerializer(new StringRedisSerializer());
return template;
}
}
如果数据类型是字符串,则不需要 template.setHashValueSerializer(new StringRedisSerializer());
和 template.setHashKeySerializer(new StringRedisSerializer());
。@Cacheable、@CacheEvict或@CachePut
等。建议类是Spring-context依赖项中的CacheInterceptor
,它是CacheAspectSupport
的子类(也来自Spring-context)。为了方便本说明,我将使用@Cacheable
作为示例来查看这里的部分源代码。@Cacheable
的方法时,AOP会将其路由到CacheAspectSupport
类中的此方法protected Collection<? extends Cache> getCaches(CacheOperationInvocationContext<CacheOperation> context, CacheResolver cacheResolver)
,其中它将尝试解析此@Cacheable
注释。反过来,它会导致在实现CacheManager中调用此方法public Cache getCache(String name)
。对于这个说明,实现的CacheManage将是RedisCacheManager
(来自Spring-data-redis依赖项)。RedisCacheManager
的关键方法:protected Cache getMissingCache(String name) {
return this.dynamic ? createCache(name) : null;
}
@SuppressWarnings("unchecked")
protected RedisCache createCache(String cacheName) {
long expiration = computeExpiration(cacheName);
return new RedisCache(cacheName, (usePrefix ? cachePrefix.prefix(cacheName) : null), redisOperations, expiration,
cacheNullValues);
}
本质上,它将实例化一个RedisCache
对象。为此,它需要4个参数,即cacheName、prefix(这是回答这个问题的关键参数)、redisOperation(也就是配置好的redisTemplate),过期时间(expiration,默认值为0)和是否缓存空值(cacheNullValues,默认值为false)。下面的构造函数展示了关于RedisCache的更多细节。
/**
* Constructs a new {@link RedisCache} instance.
*
* @param name cache name
* @param prefix must not be {@literal null} or empty.
* @param redisOperations
* @param expiration
* @param allowNullValues
* @since 1.8
*/
public RedisCache(String name, byte[] prefix, RedisOperations<? extends Object, ? extends Object> redisOperations,
long expiration, boolean allowNullValues) {
super(allowNullValues);
Assert.hasText(name, "CacheName must not be null or empty!");
RedisSerializer<?> serializer = redisOperations.getValueSerializer() != null ? redisOperations.getValueSerializer()
: (RedisSerializer<?>) new JdkSerializationRedisSerializer();
this.cacheMetadata = new RedisCacheMetadata(name, prefix);
this.cacheMetadata.setDefaultExpiration(expiration);
this.redisOperations = redisOperations;
this.cacheValueAccessor = new CacheValueAccessor(serializer);
if (allowNullValues) {
if (redisOperations.getValueSerializer() instanceof StringRedisSerializer
|| redisOperations.getValueSerializer() instanceof GenericToStringSerializer
|| redisOperations.getValueSerializer() instanceof JacksonJsonRedisSerializer
|| redisOperations.getValueSerializer() instanceof Jackson2JsonRedisSerializer) {
throw new IllegalArgumentException(String.format(
"Redis does not allow keys with null value ¯\\_(ツ)_/¯. "
+ "The chosen %s does not support generic type handling and therefore cannot be used with allowNullValues enabled. "
+ "Please use a different RedisSerializer or disable null value support.",
ClassUtils.getShortName(redisOperations.getValueSerializer().getClass())));
}
}
}
那么 RedisCache 中的 prefix
有什么用处呢?--> 如上所示,在构造函数中,它被用于以下语句:this.cacheMetadata = new RedisCacheMetadata(name, prefix);
,而下面的 RedisCacheMetadata
构造函数则展示了更多细节:
/**
* @param cacheName must not be {@literal null} or empty.
* @param keyPrefix can be {@literal null}.
*/
public RedisCacheMetadata(String cacheName, byte[] keyPrefix) {
Assert.hasText(cacheName, "CacheName must not be null or empty!");
this.cacheName = cacheName;
this.keyPrefix = keyPrefix;
StringRedisSerializer stringSerializer = new StringRedisSerializer();
// name of the set holding the keys
this.setOfKnownKeys = usesKeyPrefix() ? new byte[] {} : stringSerializer.serialize(cacheName + "~keys");
this.cacheLockName = stringSerializer.serialize(cacheName + "~lock");
}
RedisCacheMetadata
,但是这个前缀如何用于在Redis中形成键(例如,\xac\xed\x00\x05t\x00\tvc:501381,就像你所提到的那样)?CacheInterceptor
随后将继续调用上述RedisCache
对象中的private RedisCacheKey getRedisCacheKey(Object key)
方法,该方法通过利用来自RedisCacheMetadata
中的前缀和RedisOperation
中的keySerializer返回一个RedisCacheKey
实例。private RedisCacheKey getRedisCacheKey(Object key) {
return new RedisCacheKey(key).usePrefix(this.cacheMetadata.getKeyPrefix())
.withKeySerializer(redisOperations.getKeySerializer());
}
CacheInterceptor
的“pre”建议已经完成,它将继续执行由 @Cacheable
注释的实际方法。在完成实际方法的执行后,它将执行 CacheInterceptor
的“post”建议,这本质上是将结果放入 RedisCache 中。下面是将结果放入 Redis 缓存的方法:public void put(final Object key, final Object value) {
put(new RedisCacheElement(getRedisCacheKey(key), toStoreValue(value))
.expireAfter(cacheMetadata.getDefaultExpiration()));
}
/**
* Add the element by adding {@link RedisCacheElement#get()} at {@link RedisCacheElement#getKeyBytes()}. If the cache
* previously contained a mapping for this {@link RedisCacheElement#getKeyBytes()}, the old value is replaced by
* {@link RedisCacheElement#get()}.
*
* @param element must not be {@literal null}.
* @since 1.5
*/
public void put(RedisCacheElement element) {
Assert.notNull(element, "Element must not be null!");
redisOperations
.execute(new RedisCachePutCallback(new BinaryRedisCacheElement(element, cacheValueAccessor), cacheMetadata));
}
在RedisCachePutCallback
对象内部,它的回调方法doInRedis()
会实际调用一个方法来在redis中生成实际的键,该方法名为getKeyBytes()
,该方法来自于RedisCacheKey
实例。下面展示了该方法的详细信息:
/**
* Get the {@link Byte} representation of the given key element using prefix if available.
*/
public byte[] getKeyBytes() {
byte[] rawKey = serializeKeyElement();
if (!hasPrefix()) {
return rawKey;
}
byte[] prefixedKey = Arrays.copyOf(prefix, prefix.length + rawKey.length);
System.arraycopy(rawKey, 0, prefixedKey, prefix.length, rawKey.length);
return prefixedKey;
}
正如我们在getKeyBytes
方法中看到的那样,它利用了原始密钥(在您的情况下为vc:501381)和前缀密钥(在您的情况下为\xac\xed\x00\x05t\x00\t)。
使用 StringRedisTemplate
替换 RedisTemplate
。
RedisTemplate
默认使用Java序列化,StringRedisTemplate
使用 StringRedisSerializer
。
<bean id="stringRedisTemplate" class="org.springframework.data.redis.core.StringRedisTemplate">
<property name="connectionFactory" ref="jedisConnectionFactory" />
</bean>
StringRedisTemplate
仅支持字符串值。 - Madbreaks你需要将要发送到Redis的对象进行序列化。以下是完整的运行示例。它使用接口DomainObject
作为Serializable
。
以下是步骤:
1)使用以下JAR包制作您的Maven pom.xml文件
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>cglib</groupId>
<artifactId>cglib</artifactId>
<version>2.2.2</version>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-redis</artifactId>
<version>1.3.0.RELEASE</version>
</dependency>
<dependency>
<groupId>redis.clients</groupId>
<artifactId>jedis</artifactId>
<version>2.4.1</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-pool2</artifactId>
<version>2.0</version>
</dependency>
2) 将您的配置 XML 设置如下
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:c="http://www.springframework.org/schema/c"
xmlns:cache="http://www.springframework.org/schema/cache"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/cache
http://www.springframework.org/schema/cache/spring-cache.xsd">
<bean id="jeidsConnectionFactory"
class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"
p:host-name="localhost" p:port="6379" p:password="" />
<bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate"
p:connection-factory-ref="jeidsConnectionFactory" />
<bean id="imageRepository" class="com.self.common.api.poc.ImageRepository">
<property name="redisTemplate" ref="redisTemplate"/>
</bean>
</beans>
3) 将你的类定义如下
package com.self.common.api.poc;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
public class RedisMainApp {
public static void main(String[] args) throws IOException {
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("mvc-dispatcher-servlet.xml");
ImageRepository imageRepository = (ImageRepository) applicationContext.getBean("imageRepository");
BufferedImage img = ImageIO.read(new File("files/img/TestImage.png"));
BufferedImage newImg;
String imagestr;
imagestr = encodeToString(img, "png");
Image image1 = new Image("1", imagestr);
img = ImageIO.read(new File("files/img/TestImage2.png"));
imagestr = encodeToString(img, "png");
Image image2 = new Image("2", imagestr);
imageRepository.put(image1);
System.out.println(" Step 1 output : " + imageRepository.getObjects());
imageRepository.put(image2);
System.out.println(" Step 2 output : " + imageRepository.getObjects());
imageRepository.delete(image1);
System.out.println(" Step 3 output : " + imageRepository.getObjects());
}
/**
* Decode string to image
* @param imageString The string to decode
* @return decoded image
*/
public static BufferedImage decodeToImage(String imageString) {
BufferedImage image = null;
byte[] imageByte;
try {
BASE64Decoder decoder = new BASE64Decoder();
imageByte = decoder.decodeBuffer(imageString);
ByteArrayInputStream bis = new ByteArrayInputStream(imageByte);
image = ImageIO.read(bis);
bis.close();
} catch (Exception e) {
e.printStackTrace();
}
return image;
}
/**
* Encode image to string
* @param image The image to encode
* @param type jpeg, bmp, ...
* @return encoded string
*/
public static String encodeToString(BufferedImage image, String type) {
String imageString = null;
ByteArrayOutputStream bos = new ByteArrayOutputStream();
try {
ImageIO.write(image, type, bos);
byte[] imageBytes = bos.toByteArray();
BASE64Encoder encoder = new BASE64Encoder();
imageString = encoder.encode(imageBytes);
bos.close();
} catch (IOException e) {
e.printStackTrace();
}
return imageString;
}
}
package com.self.common.api.poc;
public class Image implements DomainObject {
public static final String OBJECT_KEY = "IMAGE";
public Image() {
}
public Image(String imageId, String imageAsStringBase64){
this.imageId = imageId;
this.imageAsStringBase64 = imageAsStringBase64;
}
private String imageId;
private String imageAsStringBase64;
public String getImageId() {
return imageId;
}
public void setImageId(String imageId) {
this.imageId = imageId;
}
public String getImageName() {
return imageAsStringBase64;
}
public void setImageName(String imageAsStringBase64) {
this.imageAsStringBase64 = imageAsStringBase64;
}
@Override
public String toString() {
return "User [id=" + imageAsStringBase64 + ", imageAsBase64String=" + imageAsStringBase64 + "]";
}
@Override
public String getKey() {
return getImageId();
}
@Override
public String getObjectKey() {
return OBJECT_KEY;
}
}
package com.self.common.api.poc;
import java.io.Serializable;
public interface DomainObject extends Serializable {
String getKey();
String getObjectKey();
}
package com.self.common.api.poc;
import java.util.List;
import com.self.common.api.poc.DomainObject;
public interface Repository<V extends DomainObject> {
void put(V obj);
V get(V key);
void delete(V key);
List<V> getObjects();
}
package com.self.common.api.poc;
import java.util.ArrayList;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import com.self.common.api.poc.DomainObject;
public class ImageRepository implements Repository<Image>{
@Autowired
private RedisTemplate<String,Image> redisTemplate;
public RedisTemplate<String,Image> getRedisTemplate() {
return redisTemplate;
}
public void setRedisTemplate(RedisTemplate<String,Image> redisTemplate) {
this.redisTemplate = redisTemplate;
}
@Override
public void put(Image image) {
redisTemplate.opsForHash()
.put(image.getObjectKey(), image.getKey(), image);
}
@Override
public void delete(Image key) {
redisTemplate.opsForHash().delete(key.getObjectKey(), key.getKey());
}
@Override
public Image get(Image key) {
return (Image) redisTemplate.opsForHash().get(key.getObjectKey(),
key.getKey());
}
@Override
public List<Image> getObjects() {
List<Image> users = new ArrayList<Image>();
for (Object user : redisTemplate.opsForHash().values(Image.OBJECT_KEY) ){
users.add((Image) user);
}
return users;
}
}
如果您需要更多关于Spring Jedis的参考资料,可以查看http://www.javacodegeeks.com/2012/06/using-redis-with-spring.html。
示例代码取自http://javakart.blogspot.in/2012/12/spring-data-redis-hello-world-example.html。
redisTemplate
的convertAndSend
方法时,仅更改p:keySerializer
和hashKeySerializer
是不够的。需要更改默认序列化程序
才能完成任务。 - oak