Spring-data-redis;存储对象实例

时间 2019-11-12

标签 spring data redis 存储对象实例栏目 Spring 繁體版

原文原文链接

博客分类：

Redis

spring-data-redis提供了多种serializer策略，这对使用jedis的开发者而言，实在是很是便捷。sdr提供了4种内置的serializer：redis

JdkSerializationRedisSerializer：使用JDK的序列化手段(serializable接口，ObjectInputStrean，ObjectOutputStream)，数据以字节流存储
StringRedisSerializer：字符串编码，数据以string存储
JacksonJsonRedisSerializer：json格式存储
OxmSerializer：xml格式存储

其中JdkSerializationRedisSerializer和StringRedisSerializer是最基础的序列化策略，其中“JacksonJsonRedisSerializer”与“OxmSerializer”都是基于stirng存储，所以它们是较为“高级”的序列化(最终仍是使用string解析以及构建java对象)。spring

RedisTemplate中须要声明4种serializer，默认为“JdkSerializationRedisSerializer”：json

    1) keySerializer ：对于普通K-V操做时，key采起的序列化策略
    2) valueSerializer：value采起的序列化策略
    3) hashKeySerializer：在hash数据结构中，hash-key的序列化策略
    4) hashValueSerializer：hash-value的序列化策略数据结构

不管如何，建议key/hashKey采用StringRedisSerializer。app

接下来，经过实例描述如何使用它们,能够首先参考“spring-data-redis特性”：工具

一. JdkSerializationRedisSerializer/StringRedisSerializerthis

1) spring配置文件编码

Java代码

<bean id="jedisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
<property name="connectionFactory" ref="jedisConnectionFactory"></property>
<property name="keySerializer">
<bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
</property>
<property name="hashKeySerializer">
<bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
</property>
<property name="valueSerializer">
<bean class="org.springframework.data.redis.serializer.JdkSerializationRedisSerializer"/>
</property>
<property name="hashValueSerializer">
<bean class="org.springframework.data.redis.serializer.JdkSerializationRedisSerializer"/>
</property>
</bean>

<bean id="jedisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
	<property name="connectionFactory" ref="jedisConnectionFactory"></property>
	<property name="keySerializer">
		<bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
	</property>
	<property name="hashKeySerializer">
		<bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
	</property>
	<property name="valueSerializer">
		<bean class="org.springframework.data.redis.serializer.JdkSerializationRedisSerializer"/>
	</property>
	<property name="hashValueSerializer">
		<bean class="org.springframework.data.redis.serializer.JdkSerializationRedisSerializer"/>
	</property>
</bean>

2) 程序实例：spa

Java代码

ValueOperations<String, User> valueOper = redisTemplate.opsForValue();
User user = new User("zhangsan",12);
valueOper.set("user:1", user);
System.out.println(valueOper.get("user:1").getName());

ValueOperations<String, User> valueOper = redisTemplate.opsForValue();
User user = new User("zhangsan",12);
valueOper.set("user:1", user);
System.out.println(valueOper.get("user:1").getName());

其中User为pojo类，且须要实现Serializable接口。

二.sdr与json

1) spring配置：

Java代码

<bean id="jsonSerializer" class="com.sample.redis.sdr.JsonRedisSerializer"/>
<bean id="jedisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
<property name="connectionFactory" ref="jedisConnectionFactory"></property>
<property name="defaultSerializer">
<bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
</property>
</bean>

<bean id="jsonSerializer" class="com.sample.redis.sdr.JsonRedisSerializer"/>
<bean id="jedisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
	<property name="connectionFactory" ref="jedisConnectionFactory"></property>
	<property name="defaultSerializer">
		<bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
	</property>
</bean>

并无在配置文件中，使用JacksonJsonRedisSerializer，由于这样实在是麻烦并且不灵活(主要是jackson须要ClassType)。咱们将在java代码进行转换，由于经过java代码，使用jackson工具将json字符串转换成javabean是很是简单的。

2) 程序实例：

Java代码

/**
* 不使用sdr自带的json序列化工具，一切操做基于string
**/
public class JsonRedisSeriaziler{
public static final String EMPTY_JSON = "{}";
public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");
protected ObjectMapper objectMapper = new ObjectMapper();
public JsonRedisSeriaziler(){}
/**
* java-object as json-string
* @param object
* @return
*/
public String seriazileAsString(Object object){
if (object== null) {
return EMPTY_JSON;
}
try {
return this.objectMapper.writeValueAsString(object);
} catch (Exception ex) {
throw new SerializationException("Could not write JSON: " + ex.getMessage(), ex);
}
}
/**
* json-string to java-object
* @param str
* @return
*/
public <T> T deserializeAsObject(String str,Class<T> clazz){
if(str == null || clazz == null){
return null;
}
try{
return this.objectMapper.readValue(str, clazz);
}catch (Exception ex) {
throw new SerializationException("Could not write JSON: " + ex.getMessage(), ex);
}
}
}

/**
* 不使用sdr自带的json序列化工具，一切操做基于string
**/
public class JsonRedisSeriaziler{
	public static final String EMPTY_JSON = "{}";
	
	public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");
	
	protected ObjectMapper objectMapper = new ObjectMapper();
	public JsonRedisSeriaziler(){}
	
	/**
	 * java-object as json-string
	 * @param object
	 * @return
	 */
	public String seriazileAsString(Object object){
		if (object== null) {
			return EMPTY_JSON;
		}
		try {
			return this.objectMapper.writeValueAsString(object);
		} catch (Exception ex) {
			throw new SerializationException("Could not write JSON: " + ex.getMessage(), ex);
		}
	}
	
	/**
	 * json-string to java-object
	 * @param str
	 * @return
	 */
	public <T> T deserializeAsObject(String str,Class<T> clazz){
		if(str == null || clazz == null){
			return null;
		}
		try{
			return this.objectMapper.readValue(str, clazz);
		}catch (Exception ex) {
			throw new SerializationException("Could not write JSON: " + ex.getMessage(), ex);
		}
	}

}

Java代码

public class RedisClientTest {
private JsonRedisSeriaziler seriaziler;
private RedisTemplate redisTemplate;
public void setSeriaziler(JsonRedisSeriaziler seriaziler) {
this.seriaziler = seriaziler;
}
public void setRedisTemplate(RedisTemplate redisTemplate) {
this.redisTemplate = redisTemplate;
}
public void insertUser(User user){
ValueOperations<String, String> operations = redisTemplate.opsForValue();
operations.set("user:" + user.getName(), seriaziler.seriazileAsString(user));
}
public User getUser(String name){
ValueOperations<String, String> operations = redisTemplate.opsForValue();
String json = operations.get("user:" + name);
return seriaziler.deserializeAsObject(json, User.class);
}
}