Redis @type的一个坑

redis中@type导致取数据解析报错

java.lang.ClassCastException: com.alibaba.fastjson.JSONObject cannot be cast to
新建一个对象存入redis中，对象中会出现一个字段@type

LoginUser user = new LoginUser ()
......
redisTemplate.opsForValue().set(key, user)

存入redis中数据如下

127.0.0.1:6379> get login_tokens:5be4de32-6eb5-44a5-b212-56d93e3fc067
"{\"@type\":\"com.common.core.domain.model.LoginUser\",\"deptId\":103L,\"expireTime\":1710463649132,\"token\":\"xxxx\",\"user\":{\"admin\":true,\"createBy\":\"admin\",\"dept\":{\"deptId\":103L,\"deptName\":\"xxx",\"orderNum\":1,\"params\":{\"@type\":\"java.util.HashMap\"},\"parentId\":101L,\"status\":\"0\"},\"deptId\":103L,\"loginDate\":\"2024-03-14 14:35:56\",\"loginIp\":\"127.0.0.1\",\"nickName\":\"xxx\",\"params\":{\"@type\":\"java.util.HashMap\"},\"phonenumber\":\"15888888888\",\"sex\":\"1\",\"status\":\"0\",\"userId\":1L,\"userName\":\"admin\"},\"userId\":1L,\"username\":\"admin\"}"
127.0.0.1:6379>

取数据时，redisTemplate.opsForValue().get(key);
如果LoginUser对象的包与存入时的包路径不一致，会报错java.lang.ClassCastException: com.alibaba.fastjson.JSONObject cannot be cast to

redis缓存序列化导致存储数据没有@type

在使用redis注解将数据缓存的时候发现存储进去的数据是这样的，没有@type

127.0.0.1:6379> get login_tokens:5be4de32-6eb5-44a5-b212-56d93e3fc067
"{\"deptId\":103L,\"expireTime\":1710463649132,\"token\":\"xxxx\",\"user\":{\"admin\":true,\"createBy\":\"admin\",\"dept\":{\"deptId\":103L,\"deptName\":\"xxx",\"orderNum\":1,\"parentId\":101L,\"status\":\"0\"},\"deptId\":103L,\"loginDate\":\"2024-03-14 14:35:56\",\"loginIp\":\"127.0.0.1\",\"nickName\":\"xxx\",\"phonenumber\":\"15888888888\",\"sex\":\"1\",\"status\":\"0\",\"userId\":1L,\"userName\":\"admin\"},\"userId\":1L,\"username\":\"admin\"}"
127.0.0.1:6379>

之前通过set方法放进去的数据是这样的

127.0.0.1:6379> get login_tokens:5be4de32-6eb5-44a5-b212-56d93e3fc067
"{\"@type\":\"com.common.core.domain.model.LoginUser\",\"deptId\":103L,\"expireTime\":1710463649132,\"token\":\"xxxx\",\"user\":{\"admin\":true,\"createBy\":\"admin\",\"dept\":{\"deptId\":103L,\"deptName\":\"xxx",\"orderNum\":1,\"params\":{\"@type\":\"java.util.HashMap\"},\"parentId\":101L,\"status\":\"0\"},\"deptId\":103L,\"loginDate\":\"2024-03-14 14:35:56\",\"loginIp\":\"127.0.0.1\",\"nickName\":\"xxx\",\"params\":{\"@type\":\"java.util.HashMap\"},\"phonenumber\":\"15888888888\",\"sex\":\"1\",\"status\":\"0\",\"userId\":1L,\"userName\":\"admin\"},\"userId\":1L,\"username\":\"admin\"}"
127.0.0.1:6379>

原因：
是因为set方法的序列化方法和注解的序列化方法不同

解决办法：
将序列化方法更换成set方法所使用的序列化方法

下面是序列化方法

public class FastJson2JsonRedisSerializer<T> implements RedisSerializer<T> {
    @SuppressWarnings("unused")
    private ObjectMapper objectMapper = new ObjectMapper();

    public static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;

    private Class<T> clazz;

    static {
        ParserConfig.getGlobalInstance().setAutoTypeSupport(true);
    }

    public FastJson2JsonRedisSerializer(Class<T> clazz) {
        super();
        this.clazz = clazz;
    }

    @Override
    public byte[] serialize(T t) throws SerializationException {
        if (t == null) {
            return new byte[0];
        }
        return JSON.toJSONString(t, SerializerFeature.WriteClassName).getBytes(DEFAULT_CHARSET);
    }

    @Override
    public T deserialize(byte[] bytes) throws SerializationException {
        if (bytes == null || bytes.length <= 0) {
            return null;
        }
        String str = new String(bytes, DEFAULT_CHARSET);
        return JSON.parseObject(str, clazz);
    }

    public void setObjectMapper(ObjectMapper objectMapper) {
        Assert.notNull(objectMapper, "'objectMapper' must not be null");
        this.objectMapper = objectMapper;
    }

    protected JavaType getJavaType(Class<?> clazz) {
        return TypeFactory.defaultInstance().constructType(clazz);
    }
}

SerializerFeature.WriteClassName这个序列化

public static String getString(Object object) {
   return JSON.toJSONString(object, SerializerFeature.WriteClassName);
}

如果加了SerializerFeature.WriteClassName存进redis当中的实体类就会带@type路径地址
“@type”:“com.xxx.xxx.entity.OpenNotice”

问题解决方案:去掉@type 或者 两边@type路径存放路径一致 (包名和实体类修改为一致)

去掉@type使用 JSONObject.toJSONString(obj)来存value实体类

    /**
     * hashMap存值方式
     *
     * @param parentKey
     * @param fieldKey
     * @param obj
     */
    public static void hashSet(String parentKey, String fieldKey, Object obj) {
        try {
            jedis.hset(parentKey, fieldKey, JSONObject.toJSONString(obj));
            //jedis.hset(parentKey, fieldKey, JSONParser.getString(obj)); //"@type":"com.xyz.miniLegion.entity.OpenNotice"
        } finally {
            jedis.close();
        }
    }

获取hashAll数据

   /**
     * 获取hashGetAll
     * @param parentKey
     * @return
     */
    public Map<String, String> hashGetAll(String parentKey) {
        try (Jedis jedis = pools.getResource()) { //这种写法不需要手动close();
            return jedis.hgetAll(parentKey);
        }catch (Exception e) {      
            return null;
        }
    }

测试Redis转实体类`在这里插入代码片

   @Test
    void getSoldierAttribute() {
        Map<String, String> openNoticeMap = redisPoolMgr.hashGetAll(StaticData.OpenNotice);
        //第一种根据key循环
        for (String key : openNoticeMap.keySet()) {
            OpenNotice openNotice = JSONObject.parseObject(openNoticeMap.get(key), OpenNotice.class);
            System.out.println("根据key循环:" +openNotice.getContent());
            System.out.println("根据key循环:" + JSONObject.toJSONString(openNotice));
        }
 
        //第二种根据value循环
        for (String values : openNoticeMap.values()) {
            OpenNotice openNotice = JSONObject.parseObject(values, OpenNotice.class);
            System.out.println("根据value循环:"+openNotice.getContent());
            System.out.println("根据value循环:" + JSONObject.toJSONString(openNotice));
        }
    }