Spring Boot高级教程之使用Redis实现session共享

时间:2022-09-14 16:09:31

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 BootJedis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):

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<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-redis</artifactId>
</dependency>

可以注入一个自动配置的RedisConnectionFactoryStringRedisTemplate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。

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@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:

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# 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=0

redis配置类,具体代码如下:

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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

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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:

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@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:

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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<Serializable> 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<Serializable, Object> 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<Serializable, Object> 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<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:

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@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:

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<dependency>
  <groupId>org.springframework.session</groupId>
  <artifactId>spring-session-data-redis</artifactId>
</dependency>

Session配置,具体代码如下:

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@Configuration
@EnableRedisHttpSession(maxInactiveIntervalInSeconds = 86400*30)
public class SessionConfig {
}

maxInactiveIntervalInSeconds: 设置Session失效时间,使用Redis Session之后,原Spring Bootserver.session.timeout属性不再生效。

测试实例,具体代码如下:

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@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。

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。

原文链接:https://blog.yoodb.com/yoodb/article/detail/1421