解決Jackson2反序列化LocalDateTime報錯

今天在整合redis和spring boot的時候，遇到了一個錯誤，記錄一下。

報錯如下：

Could not read JSON: Cannot construct instance of `java.time.LocalDateTime` (no Creators, like default construct, exist): cannot deserialize from Object value (no delegate- or property-based Creator)

查看后發現是數據從redis中取出時，Jackson2反序列化數據處理LocalDateTime類型時出錯，原因是：Jackson2在序列化LocalDateTime時輸出的不是普通的字符串時間格式，而是如下所示的格式（普通時間格式：2019-02-27 12:10:17）

{
    "date": {
        "year": 2019,
        "month": "FEBRUARY",
        "day": 27,
        "dayOfMonth": 27,
        "dayOfWeek": "WEDNESDAY",
        "era": [
            "java.time.chrono.IsoEra",
            "CE"
        ],
        "dayOfYear": 58,
        "leapYear": false,
        "chronology": {
            "id": "ISO",
            "calendarType": "iso8601"
        },
        "prolepticMonth": 24229,
        "monthValue": 2
    },
    "time": {
        "hour": 12,
        "minute": 10,
        "second": 17,
        "nano": 0
    },
    "month": "FEBRUARY",
    "year": 2019,
    "dayOfMonth": 27,
    "dayOfWeek": "WEDNESDAY",
    "dayOfYear": 58,
    "hour": 12,
    "minute": 10,
    "nano": 0,
    "second": 17,
    "monthValue": 2,
    "chronology": [
        "java.time.chrono.IsoChronology",
        {
            "id": "ISO",
            "calendarType": "iso8601"
        }
    ]
}

 

所以是Jackson2序列化LocalDateTime跟我們所預想的不一致，將注冊給redis的序列化模板修改成以下就行

@Configuration
public class RedisConfig {

    /**
     * 定義 UserRedisTemplate ，指定序列化和反序列化的處理類
     *
     * @param factory redis連接工廠
     * @return 模板
     */
    @Bean("UserRedisTemplate")
    public RedisTemplate<String, User> userRedisTemplate(RedisConnectionFactory factory) {
        RedisTemplate<String, User> template = new RedisTemplate<>();
        template.setConnectionFactory(factory);
        Jackson2JsonRedisSerializer<User> j2jrs = new Jackson2JsonRedisSerializer<>(User.class);
        ObjectMapper om = new ObjectMapper();
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        // 解決jackson2無法反序列化LocalDateTime的問題
18         om.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
19         om.registerModule(new JavaTimeModule());
        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY);
        j2jrs.setObjectMapper(om);
        // 序列化 value 時使用此序列化方法
        template.setValueSerializer(j2jrs);
        template.setHashValueSerializer(j2jrs);
        // 序列化 key 時
        StringRedisSerializer srs = new StringRedisSerializer();
        template.setKeySerializer(srs);
        template.setHashKeySerializer(srs);
        template.afterPropertiesSet();
        return template;
    }
}

主要是加上標紅的那兩句

 

參考文檔：

GenericJackson2JsonRedisSerializer 反序列化問題