1.添加依赖
<dependencies>

<dependency>
    <groupId>org.springframework.session</groupId>
    <artifactId>spring-session-data-redis</artifactId>
    <version>2.0.6.RELEASE</version>
    <type>pom</type>
</dependency>
<dependency>
    <groupId>io.lettuce</groupId>
    <artifactId>lettuce-core</artifactId>
    <version>5.0.5.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>5.0.9.RELEASE</version>
</dependency>

</dependencies>
2.配置session Config,添加带有如下注解的类
@EnableRedisHttpSession
public class Config {

@Bean
public LettuceConnectionFactory connectionFactory() {
    return new LettuceConnectionFactory(new RedisStandaloneConfiguration("localhost", 6379)); 
}

}
** Redis 的配置，参考Spring Data Redis
https://docs.spring.io/spring-data/data-redis/docs/2.0.10.RELEASE/reference/html

3.添加session配置到servlet 容器
public class Initializer extends AbstractHttpSessionApplicationInitializer {

public Initializer() {
    super(Config.class); 
}

}