Redis中序列化Java日期时区问题

解决方案
,
210 words , 1 mins.

现象

使用 Redis pub/sub 发布 Java 对象，订阅端服务接收到该对象后发现日期字段都差了 8 个小时。

Redis 的配置如下：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
@Configuration
@EnableCaching
public class RedisConfiguration {
    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(factory);

        ObjectMapper om = new ObjectMapper();
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        om.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);

        JavaTimeModule javaTimeModule = new JavaTimeModule();
        om.registerModule(javaTimeModule);

        Jackson2JsonRedisSerializer<Object> serializer = new Jackson2JsonRedisSerializer<>(om, Object.class);
        StringRedisSerializer stringSerializer = new StringRedisSerializer(StandardCharsets.UTF_8);

        redisTemplate.setKeySerializer(stringSerializer);
        redisTemplate.setValueSerializer(serializer);
        redisTemplate.setHashKeySerializer(stringSerializer);
        redisTemplate.setHashValueSerializer(serializer);

        redisTemplate.afterPropertiesSet();
        return redisTemplate;
    }

    @Bean
    public RedisMessageListenerContainer redisMessageListenerContainer(RedisConnectionFactory redisConnectionFactory) {
        RedisMessageListenerContainer redisMessageListenerContainer = new RedisMessageListenerContainer();
        redisMessageListenerContainer.setConnectionFactory(redisConnectionFactory);
        return redisMessageListenerContainer;
    }
}

原因

发布对象的时候没有先转成 Json，即时是在 application.yml 文件中配置了 spring.jackson.date-format 和 spring.jackson.time-zone 也无法解决时区的问题。
只能修改 RedisTemplate 序列化行为。

具体就是给 JavaTimeModule 指定自定义的序列化器，对日期类型，按照自定义逻辑进行序列化。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
ObjectMapper om = new ObjectMapper();
om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
om.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);

JavaTimeModule javaTimeModule = new JavaTimeModule();
// 指定自定义序列化器
JsonSerializer customLocalDateTimeSerializer = new CustomLocalDateTimeSerializer("yyyy-MM-dd HH:mm:ss", "Asia/Shanghai");
JsonSerializer customTimestampSerializer = new CustomTimestampSerializer("yyyy-MM-dd HH:mm:ss");
javaTimeModule.addSerializer(LocalDateTime.class, customLocalDateTimeSerializer);
javaTimeModule.addSerializer(Timestamp.class, customTimestampSerializer);

om.registerModule(javaTimeModule);
om.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));

Jackson2JsonRedisSerializer<Object> serializer = new Jackson2JsonRedisSerializer<>(om, Object.class);

CustomLocalDateTimeSerializer.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
public class CustomLocalDateTimeSerializer extends JsonSerializer<LocalDateTime> {
    private final DateTimeFormatter dateTimeFormatter;
    private final ZoneId zoneId;

    public CustomLocalDateTimeSerializer(String pattern, String zoneId) {
        this.dateTimeFormatter = DateTimeFormatter.ofPattern(pattern);
        this.zoneId = ZoneId.of(zoneId);
    }

    @Override
    public void serialize(LocalDateTime localDateTime, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
        if (localDateTime == null) {
            jsonGenerator.writeNull();
        } else {
            String formatted = localDateTime.atZone(zoneId).format(dateTimeFormatter);
            jsonGenerator.writeString(formatted);
        }
    }
}

CustomTimestampSerializer.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
public class CustomTimestampSerializer extends JsonSerializer<Timestamp> {
    private final SimpleDateFormat dateTimeFormatter;

    public CustomTimestampSerializer(String pattern) {
        this.dateTimeFormatter = new SimpleDateFormat(pattern);
    }

    @Override
    public void serialize(Timestamp timestamp, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
        if (timestamp == null) {
            jsonGenerator.writeNull();
        } else {
            String formatted = dateTimeFormatter.format(timestamp);
            jsonGenerator.writeString(formatted);
        }
    }
}

这里有个坑，被序列化的对象中的创建日期、更新日期字段是通过 MyBatis 中数据库中查出来的，查询的时候没有指定类型，默认类型是 java.sql.Timestamp，而非 java.util.Date，因此还需要额外对 java.sql.Timestamp 类型的字段创建一个新的序列化器。