redisTemplate 存取hash redistemplate存储对象

Redis是一种nosql 数据库，在开发中常用做缓存。Jedis是Redis在java中的redis- client.在此之前，希望已经了解redis的基本使用和Maven的使用。建立Maven Project之后，在POM.xml中添加jedis和spring-data-redis的依赖如下：

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1. <dependency>  
2.     <groupId>redis.clients</groupId>  
3.     <artifactId>jedis</artifactId>  
4.     <version>2.0.0</version>  
5.     <type>jar</type>  
6.     <scope>compile</scope>  
7. </dependency>  
8. <!-- spring-redis -->  
9. <dependency>  
10.     <groupId>org.springframework.data</groupId>  
11.     <artifactId>spring-data-redis</artifactId>  
12.     <version>1.0.0.RELEASE</version>  
13. </dependency>

Redis连接数据库参数如下：applicationContext-redis.properties

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1. #redis config  
2. redis.pool.maxActive=100  
3. redis.pool.maxIdle=20  
4. redis.pool.maxWait=1000  
5. redis.pool.testOnBorrow=true  
6. redis.hostname=localhost  
7. redis.port=6379  
8. redis.password=

在上下文配置中使用key-value读取方式读取properties中的值：

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1. <!-- Jedis 连接池配置-->  
2. <bean id="jedisPoolConfig" class="redis.clients.jedis.JedisPoolConfig">  
3.     <property name="maxActive" value="${redis.pool.maxActive}" />  
4.     <property name="maxIdle" value="${redis.pool.maxIdle}" />  
5.     <property name="maxWait" value="${redis.pool.maxWait}" />  
6.     <property name="testOnBorrow" value="${redis.pool.testOnBorrow}" />  
7. </bean>  
8. <!-- Jedis ConnectionFactory 数据库连接配置-->  
9. <bean id="jedisConnectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory">  
10.     <property name="hostName" value="${redis.hostname}" />  
11.     <property name="port" value="${redis.port}" />  
12.     <property name="password" value="${redis.password}" />  
13.     <property name="poolConfig" ref="jedisPoolConfig" />  
14. </bean>  
15. <!—- redisTemplate配置，redisTemplate是对Jedis的对redis操作的扩展，有更多的操作，封装使操作更便捷 -->   
16. <bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate"                                   p:connection-factory-ref="jedisConnectionFactory" />

上面redisTemplate已经基本配置完成。

接下来创建User类，必须实现或者间接实现Serializable接口：

Redis存储对象是使用序列化，spring-data-redis已经将序列化的功能内置，不需要我们去管，我们只需要调用api就可以使用。SerialVersionUID字段对序列化扩展有用，为了以后扩展或者缩减字段时不会造成反序列化出错。

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1. public class User implements Serializable {  
2.   
3.     private static final long serialVersionUID = -7898194272883238670L;  
4.   
5.     public static final String OBJECT_KEY = "USER";  
6.   
7.     public User() {  
8.     }  
9.   
10.     public User(String id) {  
11.     }  
12.   
13.     public User(String id, String name) {  
14.         this.id = id;  
15.         this.name = name;  
16.     }  
17.   
18.     private String id;  
19.   
20.     private String name;  
21.   
22.     public String getId() {  
23.         return id;  
24.     }  
25.   
26.     public void setId(String id) {  
27.         this.id = id;  
28.     }  
29.   
30.     public String getName() {  
31.         return name;  
32.     }  
33.   
34.     public void setName(String name) {  
35.         this.name = name;  
36.     }  
37.   
38.     public String toString() {  
39.         return "User [id=" + id + ", name=" + name + "]";  
40.     }  
41.   
42.     public String getKey() {  
43.         return getId();  
44.     }  
45.   
46.     public String getObjectKey() {  
47.         return OBJECT_KEY;  
48.     }  
49. }

创建userService类来操作redis增删查改缓存对象。

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1. public class UserService {  
2.   
3.     RedisTemplate<String, User> redisTemplate;  
4.   
5.     public RedisTemplate<String, User> getRedisTemplate() {  
6.         return redisTemplate;  
7.     }  
8.   
9.     public void setRedisTemplate(RedisTemplate<String, User> redisTemplate) {  
10.         this.redisTemplate = redisTemplate;  
11.     }  
12.       
13.     public void put(User user) {  
14.         redisTemplate.opsForHash().put(user.getObjectKey(), user.getKey(), user);  
15.     }  
16.   
17.     public void delete(User key) {  
18.         redisTemplate.opsForHash().delete(key.getObjectKey(), key.getKey());  
19.     }  
20.   
21.     public User get(User key) {  
22.         return (User) redisTemplate.opsForHash().get(key.getObjectKey(), key.getKey());  
23.     }  
24. }

在上下文中配置redisTemplate注入，在使用bean方式来注入时，redisTemplate必须有setter/getter方法：

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1. <bean id="userService" class="Service.UserService">  
2.     <property name="redisTemplate">  
3.         <ref bean="redisTemplate" />  
4.     </property>  
5. </bean>

======如果使用注解方式自动注入，则可以注释掉上面的bean配置方式======

在UserService注解@Service(“userService”),也可以在Service里写名字，默认是第一字母小写。

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1. @Service ("userService")  
2. public class UserService {  
3.   
4.     @Autowired  
5.     RedisTemplate<String, User> redisTemplate;  
6.     ……  
7.         ……  
8. }

在上下文配置文件中，添加自动扫描包的context节点，Base-package的路径要覆盖包含注解的类文件：

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1. <context:component-scan base-package="*" />  

在main中来简单操作一下：

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1. public class Main {  
2.     public static void main( String[] args )  
3.     {  
4.         ApplicationContext applicationContext = new ClassPathXmlApplicationContext("classpath*:/conf/applicationContext.xml"        );  
5.         UserService userService =  (UserService) applicationContext.getBean("userService");  
6.               
7.         User user1 = new User("user1ID", "User 1");  
8.         User user2 = new User("user2ID", "User 2");  
9.           
10.         System.out.println("==== getting objects from redis ====");  
11.         System.out.println("User is not in redis yet: " + userService.get(user1));  
12.         System.out.println("User is not in redis yet: " + userService.get(user2));  
13.           
14.         System.out.println("==== putting objects into redis ====");  
15.         userService.put(user1);  
16.         userService.put(user2);  
17.           
18.         System.out.println("==== getting objects from redis ====");  
19.         System.out.println("User should be in redis yet: " + userService.get(user1));  
20.         System.out.println("User should be in redis yet: " + userService.get(user2));  
21.           
22.         System.out.println("==== deleting objects from redis ====");  
23.         userService.delete(user1);  
24.         userService.delete(user2);  
25.           
26.         System.out.println("==== getting objects from redis ====");  
27.         System.out.println("User is not in redis yet: " + userService.get(user1));  
28.         System.out.println("User is not in redis yet: " + userService.get(user2));  
29.   
30.     }  
31. }

确保redis服务器是开启状态之后就可以运行程序。运行结果如下：