Redis是一個緩存消息中間件及具有豐富特性的鍵值存儲系統。Spring Boot爲Jedis客戶端庫和由Spring Data Redis提供的基於Jedis客戶端的抽象提供自動配置。spring-boot-starter-redis'Starter POM'爲收集依賴提供一種便利的方式。
引入spring-boot-starter-redis,在pom.xml配置文件中增加配置如下(基於之前章節“Spring Boot 構建框架”中的pom.xml文件):
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-redis</artifactId>
</dependency>
可以注入一個自動配置的RedisConnectionFactory,StringRedisTemplate或普通的跟其他Spring Bean相同的RedisTemplate實例。默認情況下,這個實例將嘗試使用localhost:6379連接Redis服務器。
@Component
public class MyBean {
private StringRedisTemplate template;
@Autowired
public MyBean(StringRedisTemplate template) {
this.template = template;
}
// ...
}
如果添加一個自己的任何自動配置類型的@Bean,它將替換默認的(除了RedisTemplate的情況,它是根據bean的名稱'redisTemplate'而不是它的類型進行排除的)。如果在classpath路徑下存在commons-pool2,默認會獲得一個連接池工廠。
應用使用Redis案例
添加配置文件,配置內容如下:
# REDIS (RedisProperties)
# Redis服務器地址
spring.redis.host=192.168.0.58
# Redis服務器連接端口
spring.redis.port=6379
# 連接超時時間(毫秒)
spring.redis.timeout=0
redis配置類,具體代碼如下:
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
@Component
@ConfigurationProperties(prefix = "spring.redis")
public class RedisConn {
private String host;
private int port;
private int timeout;
public String getHost() {
return host;
}
public void setHost(String host) {
this.host = host;
}
public int getPort() {
return port;
}
public void setPort(int port) {
this.port = port;
}
public int getTimeout() {
return timeout;
}
public void setTimeout(int timeout) {
this.timeout = timeout;
}
@Override
public String toString() {
return "Redis [localhost=" + host + ", port=" + port + ", timeout=" + timeout + "]";
}
}
注意:在RedisConn類中註解@ConfigurationProperties(prefix = "spring.Redis")的作用是讀取springboot的默認配置文件信息中以spring.redis開頭的信息。
配置cache類
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.interceptor.KeyGenerator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.stereotype.Component;
import com.cachemodle.RedisConn;
import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
/**
*
* @author sandsa redis cache service
*
*/
@Configuration
@EnableCaching
public class RedisConfig extends CachingConfigurerSupport {
@Autowired
private RedisConn redisConn;
/**
* 生產key的策略
*
* @return
*/
@Bean
@Override
public KeyGenerator keyGenerator() {
return new KeyGenerator() {
@Override
public Object generate(Object target, Method method, Object... params) {
StringBuilder sb = new StringBuilder();
sb.append(target.getClass().getName());
sb.append(method.getName());
for (Object obj : params) {
sb.append(obj.toString());
}
return sb.toString();
}
};
}
/**
* 管理緩存
*
* @param redisTemplate
* @return
*/
@SuppressWarnings("rawtypes")
@Bean
public CacheManager CacheManager(RedisTemplate redisTemplate) {
RedisCacheManager rcm = new RedisCacheManager(redisTemplate);
// 設置cache過期時間,時間單位是秒
rcm.setDefaultExpiration(60);
Map<String, Long> map = new HashMap<String, Long>();
map.put("test", 60L);
rcm.setExpires(map);
return rcm;
}
/**
* redis 數據庫連接池
* @return
*/
@Bean
public JedisConnectionFactory redisConnectionFactory() {
JedisConnectionFactory factory = new JedisConnectionFactory();
factory.setHostName(redisConn.getHost());
factory.setPort(redisConn.getPort());
factory.setTimeout(redisConn.getTimeout()); // 設置連接超時時間
return factory;
}
/**
* redisTemplate配置
*
* @param factory
* @return
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
@Bean
public RedisTemplate<String, String> redisTemplate(RedisConnectionFactory factory) {
StringRedisTemplate template = new StringRedisTemplate(factory);
Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
ObjectMapper om = new ObjectMapper();
om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
jackson2JsonRedisSerializer.setObjectMapper(om);
template.setValueSerializer(jackson2JsonRedisSerializer);
template.afterPropertiesSet();
return template;
}
}
分析:緩存類繼承的是CachingConfigurerSupport,它把讀取的配置文件信息的RedisConn類對象注入到這個類中。在這個類中keyGenerator()方法是key的生成策略,CacheManager()方法是緩存管理策略,redisConnectionFactory()是redis連接,redisTemplate()方法是redisTemplate配置信息,配置後使redis中能存儲Java對象。
測試配置是否成功,實例:
@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(Application.class)
public class TestRedis {
@Autowired
private StringRedisTemplate stringRedisTemplate; // 處理字符串
@Autowired
private RedisTemplate redisTemplate; // 處理對象
@Test
public void test() throws Exception {
stringRedisTemplate.opsForValue().set("yoodb", "123");
Assert.assertEquals("123", stringRedisTemplate.opsForValue().get("yoodb"));
}
}
簡單封裝的Redis工具類,代碼如下:
import java.io.Serializable;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Component;
@Component
public class RedisUtils {
@SuppressWarnings("rawtypes")
@Autowired
private RedisTemplate redisTemplate;
/**
* 批量刪除對應的value
*
* @param keys
*/
public void remove(final String... keys) {
for (String key : keys) {
remove(key);
}
}
/**
* 批量刪除key
*
* @param pattern
*/
@SuppressWarnings("unchecked")
public void removePattern(final String pattern) {
Set<Serializable> keys = redisTemplate.keys(pattern);
if (keys.size() > 0)
redisTemplate.delete(keys);
}
/**
* 刪除對應的value
*
* @param key
*/
@SuppressWarnings("unchecked")
public void remove(final String key) {
if (exists(key)) {
redisTemplate.delete(key);
}
}
/**
* 判斷緩存中是否有對應的value
*
* @param key
* @return
*/
@SuppressWarnings("unchecked")
public boolean exists(final String key) {
return redisTemplate.hasKey(key);
}
/**
* 讀取緩存
*
* @param key
* @return
*/
@SuppressWarnings("unchecked")
public Object get(final String key) {
Object result = null;
ValueOperations<Serializable, Object> operations = redisTemplate.opsForValue();
result = operations.get(key);
return result;
}
/**
* 寫入緩存
*
* @param key
* @param value
* @return
*/
@SuppressWarnings("unchecked")
public boolean set(final String key, Object value) {
boolean result = false;
try {
ValueOperations<Serializable, Object> operations = redisTemplate.opsForValue();
operations.set(key, value);
result = true;
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
/**
* 寫入緩存
*
* @param key
* @param value
* @return
*/
@SuppressWarnings("unchecked")
public boolean set(final String key, Object value, Long expireTime) {
boolean result = false;
try {
ValueOperations<Serializable, Object> operations = redisTemplate.opsForValue();
operations.set(key, value);
redisTemplate.expire(key, expireTime, TimeUnit.SECONDS);
result = true;
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
}
查詢數據庫時自動使用緩存,根據方法生成緩存,參考代碼如下:
@Service
public class UserService {
@Cacheable(value = "redis-key")
public UserInfo getUserInfo(Long id, String sex, int age, String name) {
System.out.println("無緩存時調用----數據庫查詢");
return new UserInfo(id, sex, age, name);
}
}
注意:value的值就是緩存到redis中的key,此key是需要自己在進行增加緩存信息時定義的key,用於標識唯一性的。
Session 共享
分佈式系統中session共享有很多不錯的解決方案,其中託管到緩存中是比較常見的方案之一,下面利用Session-spring-session-data-redis實現session共享。
引入依賴,在pom.xml配置文件中增加如下內容:
<dependency>
<groupId>org.springframework.session</groupId>
<artifactId>spring-session-data-redis</artifactId>
</dependency>
Session配置,具體代碼如下:
@Configuration
@EnableRedisHttpSession(maxInactiveIntervalInSeconds = 86400*30)
public class SessionConfig {
}
maxInactiveIntervalInSeconds: 設置Session失效時間,使用Redis Session之後,原Spring Boot的server.session.timeout屬性不再生效。
測試實例,具體代碼如下:
@RequestMapping("uid")
String uid(HttpSession session) {
UUID uid = (UUID) session.getAttribute("uid");
if (uid == null) {
uid = UUID.randomUUID();
}
session.setAttribute("uid", uid);
return session.getId();
}
登錄redis服務端,輸入命令keys 'session*',查看緩存是否成功。