Spring Boot使用Redis实现session共享
Redis是一个缓存消息中间件及具有丰富特性的键值存储系统。Spring Boot为Jedis客户端库和由Spring Data Redis提供的基于Jedis客户端的抽象提供自动配置。spring-boot-starter-redis'Starter POM'为收集依赖提供一种便利的方式。
引入spring-boot-starter-redis，在pom.xml配置文件中增加配置如下（基于之前章节“Spring Boot 构建框架”中的pom.xml文件）：
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-redisartifactId>
dependency>可以注入一个自动配置的RedisConnectionFactory，StringRedisTemplate或普通的跟其他Spring Bean相同的RedisTemplate实例。默认情况下，这个实例将尝试使用localhost:6379连接Redis服务器。
@Component
public class MyBean {
private StringRedisTemplate template;
@Autowired
public MyBean(StringRedisTemplate template) {
this.template = template;
}
// ...
}如果添加一个自己的任何自动配置类型的@Bean，它将替换默认的（除了RedisTemplate的情况，它是根据bean的名称'redisTemplate'而不是它的类型进行排除的）。如果在classpath路径下存在commons-pool2，默认会获得一个连接池工厂。
应用使用Redis案例
添加配置文件，配置内容如下：
# REDIS (RedisProperties)
# Redis服务器地址
spring.redis.host=192.168.0.58
# Redis服务器连接端口
spring.redis.port=6379
# 连接超时时间（毫秒）
spring.redis.timeout=0redis配置类，具体代码如下：
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类中注解@ConfigurationProperties(prefix = "spring.Redis")的作用是读取springboot的默认配置文件信息中以spring.redis开头的信息。
配置cache类
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;
/**
* 生产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();
}
};
}
/**
* 管理缓存
*
* @param redisTemplate
* @return
*/
@SuppressWarnings("rawtypes")
@Bean
public CacheManager CacheManager(RedisTemplate redisTemplate) {
RedisCacheManager rcm = new RedisCacheManager(redisTemplate);
// 设置cache过期时间,时间单位是秒
rcm.setDefaultExpiration(60);
Map<String, Long> map = new HashMap<String, Long>();
map.put("test", 60L);
rcm.setExpires(map);
return rcm;
}
/**
* redis 数据库连接池
* @return
*/
@Bean
public JedisConnectionFactory redisConnectionFactory() {
JedisConnectionFactory factory = new JedisConnectionFactory();
factory.setHostName(redisConn.getHost());
factory.setPort(redisConn.getPort());
factory.setTimeout(redisConn.getTimeout()); // 设置连接超时时间
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：缓存类继承的是CachingConfigurerSupport，它把读取的配置文件信息的RedisConn类对象注入到这个类中。在这个类中keyGenerator()方法是key的生成策略，CacheManager()方法是缓存管理策略，redisConnectionFactory()是redis连接，redisTemplate()方法是redisTemplate配置信息，配置后使redis中能存储Java对象。
测试配置是否成功，实例：
@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(Application.class)
public class TestRedis {
@Autowired
private StringRedisTemplate stringRedisTemplate; // 处理字符串
@Autowired
private RedisTemplate redisTemplate; // 处理对象
@Test
public void test() throws Exception {
stringRedisTemplate.opsForValue().set("yoodb", "123");
Assert.assertEquals("123", stringRedisTemplate.opsForValue().get("yoodb"));
}
}简单封装的Redis工具类，代码如下：
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;
/**
* 批量删除对应的value
*
* @param keys
*/
public void remove(final String... keys) {
for (String key : keys) {
remove(key);
}
}
/**
* 批量删除key
*
* @param pattern
*/
@SuppressWarnings("unchecked")
public void removePattern(final String pattern) {
Set keys = redisTemplate.keys(pattern);
if (keys.size() > 0)
redisTemplate.delete(keys);
}
/**
* 删除对应的value
*
* @param key
*/
@SuppressWarnings("unchecked")
public void remove(final String key) {
if (exists(key)) {
redisTemplate.delete(key);
}
}
/**
* 判断缓存中是否有对应的value
*
* @param key
* @return
*/
@SuppressWarnings("unchecked")
public boolean exists(final String key) {
return redisTemplate.hasKey(key);
}
/**
* 读取缓存
*
* @param key
* @return
*/
@SuppressWarnings("unchecked")
public Object get(final String key) {
Object result = null;
ValueOperations operations = redisTemplate.opsForValue();
result = operations.get(key);
return result;
}
/**
* 写入缓存
*
* @param key
* @param value
* @return
*/
@SuppressWarnings("unchecked")
public boolean set(final String key, Object value) {
boolean result = false;
try {
ValueOperations operations = redisTemplate.opsForValue();
operations.set(key, value);
result = true;
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
/**
* 写入缓存
*
* @param key
* @param value
* @return
*/
@SuppressWarnings("unchecked")
public boolean set(final String key, Object value, Long expireTime) {
boolean result = false;
try {
ValueOperations operations = redisTemplate.opsForValue();
operations.set(key, value);
redisTemplate.expire(key, expireTime, TimeUnit.SECONDS);
result = true;
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
} 查询数据库时自动使用缓存，根据方法生成缓存，参考代码如下：
@Service
public class UserService {
@Cacheable(value = "redis-key")
public UserInfo getUserInfo(Long id, String sex, int age, String name) {
System.out.println("无缓存时调用----数据库查询");
return new UserInfo(id, sex, age, name);
}
}注意：value的值就是缓存到redis中的key，此key是需要自己在进行增加缓存信息时定义的key，用于标识唯一性的。
Session 共享
分布式系统中session共享有很多不错的解决方案，其中托管到缓存中是比较常见的方案之一，下面利用Session-spring-session-data-redis实现session共享。
引入依赖，在pom.xml配置文件中增加如下内容：
<dependency>
<groupId>org.springframework.sessiongroupId>
<artifactId>spring-session-data-redisartifactId>
dependency>Session配置，具体代码如下：
@Configuration
@EnableRedisHttpSession(maxInactiveIntervalInSeconds = 86400*30)
public class SessionConfig {
}maxInactiveIntervalInSeconds: 设置Session失效时间，使用Redis Session之后，原Spring Boot的server.session.timeout属性不再生效。
测试实例，具体代码如下：
@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();
}登录redis服务端，输入命令keys 'session*'，查看缓存是否成功。