Maven中Spring-Data-Redis存儲對象(redisTemplate)

時間 2019-11-26

標籤 maven spring data redis 存儲對象 redistemplate 欄目 Maven 简体版

原文原文鏈接

Redis是一種nosql 數據庫，在開發中經常使用作緩存。Jedis是Redis在java中的redis- client.在此以前，但願已經瞭解redis的基本使用和Maven的使用。創建Maven Project以後，在POM.xml中添加jedis和spring-data-redis的依賴以下：html

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<dependency> redis
<groupId>redis.clients</groupId> spring
<artifactId>jedis</artifactId> sql
<version>2.0.0</version> 數據庫
<type>jar</type> api
<scope>compile</scope> 緩存
</dependency> 服務器
app
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-redis</artifactId>
<version>1.0.0.RELEASE</version>
</dependency>

Redis鏈接數據庫參數以下：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讀取方式讀取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是對Jedis的對redis操做的擴展，有更多的操做，封裝使操做更便捷 -->
<bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate" p:connection-factory-ref="jedisConnectionFactory" />

上面redisTemplate已經基本配置完成。

接下來建立User類，必須實現或者間接實現Serializable接口：

Redis存儲對象是使用序列化，spring-data-redis已經將序列化的功能內置，不須要咱們去管，咱們只須要調用api就可使用。SerialVersionUID字段對序列化擴展有用，爲了之後擴展或者縮減字段時不會形成反序列化出錯。

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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類來操做redis增刪查改緩存對象。

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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方式來注入時，redisTemplate必須有setter/getter方法：

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

======若是使用註解方式自動注入，則能夠註釋掉上面的bean配置方式======

在UserService註解@Service(「userService」),也能夠在Service裏寫名字，默認是第一字母小寫。

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

在上下文配置文件中，添加自動掃描包的context節點，Base-package的路徑要覆蓋包含註解的類文件：

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

在main中來簡單操做一下：

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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));
}
}