Spring Boot与Spring Session集成

1. 参考资料

• https://docs.spring.io/spring-session/docs/current/reference/html5/guides/boot-redis.html
• https://docs.spring.io/spring-boot/docs/2.0.2.RELEASE/reference/htmlsingle/#boot-features-session

2. 环境

Java: jdk1.8.0_144
Spring Boot: 2.0.1.RELEASE

3. 配置

本文前提是已使用Spring Boot搭建了一个Web应用，在此基础上集成Spring Session以使用Redis管理该应用的session

• 引入依赖包

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

• Spring Session配置

spring.session.store-type=redis

配置该属性后，应用启动时将创建名为springSessionRepositoryFilter的过滤器，它负责在后台把javax.servlet.http.HttpSession的实现替换为Spring Session，更多的配置示例

spring.session.redis.flush-mode=on-save
spring.session.redis.namespace=spring:session
server.servlet.session.timeout=1800

• Redis连接配置

spring.redis.host=127.0.0.1
spring.redis.password=123456
spring.redis.port=6379

应用将自动创建RedisConnectionFactory并连接目标Redis Server

4. Redis存储结构

对象结构存入javax.servlet.http.HttpSession，最终需要以字节或者字符的形式存入Redis，故可以指定序列化与反序列方法(例如org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer)，若未指定则使用JDK自带的java.io.Serializable，以下面的类为例说明执行httpSession.setAttribute("verify", verify)在使用不同序列化方法时的表现

public class Verify {
    private String code;// 如 1 + 2
    private Integer value;// 如 3

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public Integer getValue() {
        return value;
    }

    public void setValue(Integer value) {
        this.value = value;
    }
}

• java.io.Serializable

此时Verify类必须实现java.io.Serializable接口，否则抛出异常

Caused by: java.lang.IllegalArgumentException: DefaultSerializer requires a Serializable payload but received an object of type [org.*.Verify]
	at org.springframework.core.serializer.DefaultSerializer.serialize(DefaultSerializer.java:43)
	at org.springframework.core.serializer.support.SerializingConverter.convert(SerializingConverter.java:63)
	... 37 common frames omitted

Redis中的结构示例：

127.0.0.1:6379> keys *
1) "spring:session:sessions:d850410a-557d-4b01-b194-9af0c3336517"
2) "spring:session:expirations:1529485860000"
3) "spring:session:sessions:expires:d850410a-557d-4b01-b194-9af0c3336517"
127.0.0.1:6379> HGETALL spring:session:sessions:d850410a-557d-4b01-b194-9af0c3336517
1) "maxInactiveInterval"
2) "\xac\xed\x00\x05sr\x00\x11java.lang.Integer\x12\xe2\xa0\xa4\xf7\x81\x878\x02\x00\x01I\x00\x05valuexr\x00\x10java.lang.Number\x86\xac\x95\x1d\x0b\x94\xe0\x8b\x02\x00\x00xp\x00\x00\a\b"
3) "sessionAttr:verify"
4) "\xac\xed\x00\x05sr\x00 org.lxp.dailylog.web.util.Verify\x00\x00\x00\x00\x00\x00\x00\x01\x02\x00\x02L\x00\x04codet\x00\x12Ljava/lang/String;L\x00\x05valuet\x00\x13Ljava/lang/Integer;xpt\x00\a1 + 5=?sr\x00\x11java.lang.Integer\x12\xe2\xa0\xa4\xf7\x81\x878\x02\x00\x01I\x00\x05valuexr\x00\x10java.lang.Number\x86\xac\x95\x1d\x0b\x94\xe0\x8b\x02\x00\x00xp\x00\x00\x00\x06"
5) "creationTime"
6) "\xac\xed\x00\x05sr\x00\x0ejava.lang.Long;\x8b\xe4\x90\xcc\x8f#\xdf\x02\x00\x01J\x00\x05valuexr\x00\x10java.lang.Number\x86\xac\x95\x1d\x0b\x94\xe0\x8b\x02\x00\x00xp\x00\x00\x01d\x1cZSC"
7) "lastAccessedTime"
8) "\xac\xed\x00\x05sr\x00\x0ejava.lang.Long;\x8b\xe4\x90\xcc\x8f#\xdf\x02\x00\x01J\x00\x05valuexr\x00\x10java.lang.Number\x86\xac\x95\x1d\x0b\x94\xe0\x8b\x02\x00\x00xp\x00\x00\x01d\x1cZSC"
127.0.0.1:6379> 

• org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializer;

@Configuration
public class JedisConfig {
    @Bean
    public RedisSerializer<Object> springSessionDefaultRedisSerializer() {
        return new Jackson2JsonRedisSerializer<>(Object.class);
    }
}

Redis中的结构示例：

127.0.0.1:6379> keys *
1) "spring:session:expirations:1529486220000"
2) "spring:session:sessions:expires:8a804a79-862e-4e05-9fc0-e8db7cbf33f9"
3) "spring:session:sessions:8a804a79-862e-4e05-9fc0-e8db7cbf33f9"
127.0.0.1:6379> HGETALL spring:session:sessions:8a804a79-862e-4e05-9fc0-e8db7cbf33f9
1) "lastAccessedTime"
2) "1529484404321"
3) "sessionAttr:verify"
4) "{\"code\":\"8 + 10=?\",\"value\":18}"
5) "maxInactiveInterval"
6) "1800"
7) "creationTime"
8) "1529484404321"