Spring Boot 整合 Redis

Redis

配置文件

<!-- pom.xml-->
<dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

Redis的配置文件集中在RedisProperties中，配置文件中以spring.redis前缀开头。

以下列出一些常用配置：

@ConfigurationProperties(prefix = "spring.redis")
public class RedisProperties {
    private int database = 0;  //使用的数据库下标
    private String host = "localhost";  
    private String password;
    private int port = 6379;
    private boolean ssl;
    private Duration timeout;  //超时时间
    private RedisProperties.Sentinel sentinel;  //哨兵模式
    private RedisProperties.Cluster cluster;     //集群模式
    
     public static class Sentinel {
        private String master;
        private List<String> nodes;
     }
    
    public static class Cluster {
        private List<String> nodes;
        private Integer maxRedirects;
    }
    
     public static class Pool {
        private int maxIdle = 8;
        private int minIdle = 0;
        private int maxActive = 8;
        private Duration maxWait = Duration.ofMillis(-1L);
        private Duration timeBetweenEvictionRuns;
     }
}

#application.properties
spring.redis.host= localhost
spring.redis.port=6379
spring.redis.password=

自动配置

@Configuration
@ConditionalOnClass(RedisOperations.class)
@EnableConfigurationProperties(RedisProperties.class)
@Import({ LettuceConnectionConfiguration.class, JedisConnectionConfiguration.class })
public class RedisAutoConfiguration {

  @Bean
  @ConditionalOnMissingBean(name = "redisTemplate")
  public RedisTemplate<Object, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory)
			throws UnknownHostException {
    RedisTemplate<Object, Object> template = new RedisTemplate<>();
    template.setConnectionFactory(redisConnectionFactory);
    return template;
  }

  @Bean
  @ConditionalOnMissingBean
  public StringRedisTemplate stringRedisTemplate(RedisConnectionFactory redisConnectionFactory)
			throws UnknownHostException {
    StringRedisTemplate template = new StringRedisTemplate();
    template.setConnectionFactory(redisConnectionFactory);
    return template;
  }
}

可以看到RedisAutoConfiguration默认创建两个Bean，其中创建了一个主要以String类型操作的stringRedisTemplate，也就是说可以直接通过注解使用这些Bean。

RedisAutoConfiguration初始化两个Bean时使用了@ConditionalOnMissingBean注解，如果我们想要自己实现初始化Bean，只需要自行编写个配置类注入Bean组件即可。

序列化

redisTemplate如果保存的是对象时，默认使用JdkSerializationRedisSerializer类作为序列化机制，将对象序列化后的数据（非明文）存储到redis数据库中。Redis规定序列化机制的实现类需要实现RedisSerializer接口。

public interface RedisSerializer<T> {

  @Nullable
  static RedisSerializer<Object> java(@Nullable ClassLoader classLoader) {
    return new JdkSerializationRedisSerializer(classLoader);
  }

  static RedisSerializer<Object> json() {
    return new GenericJackson2JsonRedisSerializer();
  }

  static RedisSerializer<String> string() {
    return StringRedisSerializer.UTF_8;
  }
}

在不配置的情况下，默认JDK序列化机制，普遍情况下，我们习惯把对象以String或者JSON的结构存储到Redis，这时候需要手动配置序列化机制，而只要我们引入了相关的依赖包，如FastJson，就能够找到对应的序列化器FastJsonRedisSerializer。

redis-1

@Configuration
public class MyRedisConfig {
    
    //手动配置redisTemplate
    @Bean
    public RedisTemplate<Object, Object> redisTemplate(
            RedisConnectionFactory redisConnectionFactory)
            throws UnknownHostException {
        RedisTemplate<Object, Object> template = new RedisTemplate<Object, Object>();
        template.setConnectionFactory(redisConnectionFactory);
        FastJsonRedisSerializer<Object> ser = new FastJsonRedisSerializer<Object>(Object.class);
        //设置默认序列化器，对所有的key-value类型都生效
        template.setDefaultSerializer(ser);
        return template;
    }
}

测试

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringbootApplicationTests {
  @Autowired
  EmployeeMapper employeeMapper;

  @Autowired
  StringRedisTemplate stringRedisTemplate;  //操作k-v都是字符串的

  @Autowired
  RedisTemplate redisTemplate;  //k-v都是对象的


  /**
	 * Redis常见的五大数据类型
	 *  String（字符串）、List（列表）、Set（集合）、Hash（散列）、ZSet（有序集合）
	 *  stringRedisTemplate.opsForValue()[String（字符串）]
	 *  stringRedisTemplate.opsForList()[List（列表）]
	 *  stringRedisTemplate.opsForSet()[Set（集合）]
	 *  stringRedisTemplate.opsForHash()[Hash（散列）]
	 *  stringRedisTemplate.opsForZSet()[ZSet（有序集合）]
	 */
  @Test
  public void test01(){
    //给redis中保存数据
      stringRedisTemplate.opsForValue().append("msg","hello");
        String msg = stringRedisTemplate.opsForValue().get("msg");
        System.out.println(msg);

        stringRedisTemplate.opsForList().leftPush("mylist","1");
        stringRedisTemplate.opsForList().leftPush("mylist","2");
  }

  //测试保存对象
  @Test
  public void test02(){
    Employee emp = new Employee("张三","男");
    //默认如果保存对象，使用jdk序列化机制，序列化后的数据保存到redis中
    //配置redisTemplate的序列化机制，将对象数据以JSON的方式保存
    redisTemplate.opsForValue().set("emp-01",emp);
  }