Maven中Spring-Data-Redis存储对象(redisTemplate)

时间 2019-11-26

标签 maven spring data redis 存储对象 redistemplate 栏目 Maven 繁體版

原文原文链接

Redis是一种nosql 数据库，在开发中经常使用作缓存。Jedis是Redis在java中的redis- client.在此以前，但愿已经了解redis的基本使用和Maven的使用。创建Maven Project以后，在POM.xml中添加jedis和spring-data-redis的依赖以下：html

[html] view plain copy java

<dependency> redis
<groupId>redis.clients</groupId> spring
<artifactId>jedis</artifactId> sql
<version>2.0.0</version> 数据库
<type>jar</type> api
<scope>compile</scope> 缓存
</dependency> 服务器
app
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-redis</artifactId>
<version>1.0.0.RELEASE</version>
</dependency>

Redis链接数据库参数以下：applicationContext-redis.properties

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#redis config
redis.pool.maxActive=100
redis.pool.maxIdle=20
redis.pool.maxWait=1000
redis.pool.testOnBorrow=true
redis.hostname=localhost
redis.port=6379
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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<bean id="jedisPoolConfig" class="redis.clients.jedis.JedisPoolConfig">
<property name="maxActive" value="${redis.pool.maxActive}" />
<property name="maxIdle" value="${redis.pool.maxIdle}" />
<property name="maxWait" value="${redis.pool.maxWait}" />
<property name="testOnBorrow" value="${redis.pool.testOnBorrow}" />
</bean>
<bean id="jedisConnectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory">
<property name="hostName" value="${redis.hostname}" />
<property name="port" value="${redis.port}" />
<property name="password" value="${redis.password}" />
<property name="poolConfig" ref="jedisPoolConfig" />
</bean>
<!—- redisTemplate配置，redisTemplate是对Jedis的对redis操做的扩展，有更多的操做，封装使操做更便捷 -->
<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。

接下来建立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，不须要咱们去管，咱们只须要调用api就可使用。SerialVersionUID字段对序列化扩展有用，为了之后扩展或者缩减字段时不会形成反序列化出错。

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public class User implements Serializable {
private static final long serialVersionUID = -7898194272883238670L;
public static final String OBJECT_KEY = "USER";
public User() {
}
public User(String id) {
}
public User(String id, String name) {
this.id = id;
this.name = name;
}
private String id;
private String name;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String toString() {
return "User [id=" + id + ", name=" + name + "]";
}
public String getKey() {
return getId();
}
public String getObjectKey() {
return OBJECT_KEY;
}
}

建立userService类来操做redis增删查改缓存对象。

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public class UserService {
RedisTemplate<String, User> redisTemplate;
public RedisTemplate<String, User> getRedisTemplate() {
return redisTemplate;
}
public void setRedisTemplate(RedisTemplate<String, User> redisTemplate) {
this.redisTemplate = redisTemplate;
}
public void put(User user) {
redisTemplate.opsForHash().put(user.getObjectKey(), user.getKey(), user);
}
public void delete(User key) {
redisTemplate.opsForHash().delete(key.getObjectKey(), key.getKey());
}
public User get(User key) {
return (User) redisTemplate.opsForHash().get(key.getObjectKey(), key.getKey());
}
}

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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<bean id="userService" class="Service.UserService">
<property name="redisTemplate">
<ref bean="redisTemplate" />
</property>
</bean>

======若是使用注解方式自动注入，则能够注释掉上面的bean配置方式======

在UserService注解@Service(“userService”),也能够在Service里写名字，默认是第一字母小写。

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@Service ("userService")
public class UserService {
@Autowired
RedisTemplate<String, User> redisTemplate;
……
……
}

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

在main中来简单操做一下：

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public class Main {
public static void main( String[] args )
{
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("classpath*:/conf/applicationContext.xml" );
UserService userService = (UserService) applicationContext.getBean("userService");
User user1 = new User("user1ID", "User 1");
User user2 = new User("user2ID", "User 2");
System.out.println("==== getting objects from redis ====");
System.out.println("User is not in redis yet: " + userService.get(user1));
System.out.println("User is not in redis yet: " + userService.get(user2));
System.out.println("==== putting objects into redis ====");
userService.put(user1);
userService.put(user2);
System.out.println("==== getting objects from redis ====");
System.out.println("User should be in redis yet: " + userService.get(user1));
System.out.println("User should be in redis yet: " + userService.get(user2));
System.out.println("==== deleting objects from redis ====");
userService.delete(user1);
userService.delete(user2);
System.out.println("==== getting objects from redis ====");
System.out.println("User is not in redis yet: " + userService.get(user1));
System.out.println("User is not in redis yet: " + userService.get(user2));
}
}

确保redis服务器是开启状态以后就能够运行程序。运行结果以下：