今天在使用easyexcel进行导出时发现导出的excel中只有表头没有数据,经过本地调试发现List中是有数据的,由于List是有redis缓存,所以我直接将redis中的缓存删掉让他重新去数据库加载,发现从数据库加载出来的List是可以写入到excel中,但是后续从redis获取的List就无法写入excel,最终发现应该是反序列化没有配置好。

RedisConfig


import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.StringRedisSerializer;

/**
 * redis配置
 */
@Configuration
public class RedisConfig extends CachingConfigurerSupport
{
	@Bean
    @SuppressWarnings("all")
    public RedisTemplate<Object, Object> redisTemplate(RedisConnectionFactory connectionFactory)
    {
        RedisTemplate<Object, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(connectionFactory);

        FastJson2JsonRedisSerializer serializer = new FastJson2JsonRedisSerializer(Object.class);

        // 使用StringRedisSerializer来序列化和反序列化redis的key值
        template.setKeySerializer(new StringRedisSerializer());
        template.setValueSerializer(serializer);

        // Hash的key也采用StringRedisSerializer的序列化方式
        template.setHashKeySerializer(new StringRedisSerializer());
        template.setHashValueSerializer(serializer);

        template.afterPropertiesSet();
        return template;
    }
}

FastJson2JsonRedisSerializer


import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.JSONReader;
import com.alibaba.fastjson2.JSONWriter;
import com.alibaba.fastjson2.filter.Filter;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.SerializationException;

import java.nio.charset.Charset;

/**
 * Redis使用FastJson序列化
 */
public class FastJson2JsonRedisSerializer<T> implements RedisSerializer<T>
{
    /**
     * 自动识别json对象白名单配置(仅允许解析的包名,范围越小越安全)
     */
    public static final String[] JSON_WHITELIST_STR = { "org.springframework", "com.cntaiping.risk" };
    
    public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");
    
    static final Filter AUTO_TYPE_FILTER = JSONReader.autoTypeFilter(JSON_WHITELIST_STR);
    
    private Class<T> clazz;
    
    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, JSONWriter.Feature.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 (T)JSON.parseObject(str, clazz, AUTO_TYPE_FILTER);
    }
}

Redis工具类


import cn.hutool.core.bean.BeanUtil;
import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.TypeReference;
import org.apache.commons.collections4.ListUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.BoundSetOperations;
import org.springframework.data.redis.core.Cursor;
import org.springframework.data.redis.core.HashOperations;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ScanOptions;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Component;

import java.util.*;
import java.util.concurrent.TimeUnit;

/**
 * spring redis 工具类
 *
 **/
@Component
public class RedisService
{
    @Autowired
    public RedisTemplate redisTemplate;

    /**
     * 缓存基本的对象,Integer、String、实体类等
     *
     * @param key 缓存的键值
     * @param value 缓存的值
     */
    public <T> void setCacheObject(final String key, final T value)
    {
        redisTemplate.opsForValue().set(key, value);
    }

    public <T> void increment(final String key, final int delta)
    {
        redisTemplate.opsForValue().increment(key,delta);
    }

    /**
     * 缓存基本的对象,Integer、String、实体类等
     *
     * @param key 缓存的键值
     * @param value 缓存的值
     * @param timeout 时间
     * @param timeUnit 时间颗粒度
     */
    public <T> void setCacheObject(final String key, final T value, final Long timeout, final TimeUnit timeUnit)
    {
        redisTemplate.opsForValue().set(key, value, timeout, timeUnit);
    }

    /**
     * 设置有效时间
     *
     * @param key Redis键
     * @param timeout 超时时间
     * @return true=设置成功;false=设置失败
     */
    public boolean expire(final String key, final long timeout)
    {
        return expire(key, timeout, TimeUnit.SECONDS);
    }

    /**
     * 设置有效时间
     *
     * @param key Redis键
     * @param timeout 超时时间
     * @param unit 时间单位
     * @return true=设置成功;false=设置失败
     */
    public boolean expire(final String key, final long timeout, final TimeUnit unit)
    {
        return redisTemplate.expire(key, timeout, unit);
    }

    /**
     * 获取有效时间
     *
     * @param key Redis键
     * @return 有效时间
     */
    public long getExpire(final String key)
    {
        return redisTemplate.getExpire(key);
    }

    /**
     * 判断 key是否存在
     *
     * @param key 键
     * @return true 存在 false不存在
     */
    public Boolean hasKey(String key)
    {
        return redisTemplate.hasKey(key);
    }

    /**
     * 获得缓存的基本对象。
     *
     * @param key 缓存键值
     * @return 缓存键值对应的数据
     */
    public <T> T getCacheObject(final String key)
    {
        ValueOperations<String, T> operation = redisTemplate.opsForValue();
        return operation.get(key);
    }
    
    /**
     * 读取 setCacheObject 方法的值是一个List<Object>时反序列化的方法 否则序列化时会返回 JsonArray<JsonObject>
     */
    public <T> T getCacheObject(final String key, TypeReference<T> typeReference) {
        ValueOperations<String, T> operation = redisTemplate.opsForValue();
        // 使用FastJson根据TypeReference反序列化
        return JSON.parseObject(JSON.toJSONString(operation.get(key)), typeReference);
    }

    /**
     * 删除单个对象
     *
     * @param key
     */
    public boolean deleteObject(final String key)
    {
        return redisTemplate.delete(key);
    }

    /**
     * 删除集合对象
     *
     * @param collection 多个对象
     * @return
     */
    public boolean deleteObject(final Collection collection)
    {
        return redisTemplate.delete(collection) > 0;
    }

    /**
     * 缓存List数据
     *
     * @param key 缓存的键值
     * @param dataList 待缓存的List数据
     * @return 缓存的对象
     */
    public <T> long setCacheList(final String key, final List<T> dataList)
    {
        Long count = redisTemplate.opsForList().rightPushAll(key, dataList);
        return count == null ? 0 : count;
    }

    /**
     * 缓存List数据
     *
     * @param key 缓存的键值
     * @return 缓存的对象
     */
    public <T> long setObjectToList(final String key,Object data)
    {
        Long count = redisTemplate.opsForList().rightPush(key, data);
        return count == null ? 0 : count;
    }

    /**
     * 缓存List数据
     *
     * @param key 缓存的键值
     * @return 缓存的对象
     */
    public <T> long getCacheListSize(final String key)
    {
        return redisTemplate.opsForList().size(key);
    }

    public <T> T popCacheList(final String key,Class<T> clazz)
    {
        Object value = redisTemplate.opsForList().leftPop(key);
        return BeanUtil.toBean(value, clazz);
    }

    /**
     * 获得缓存的list对象
     *
     * @param key 缓存的键值
     * @return 缓存键值对应的数据
     */
    public <T> List<T> getCacheList(final String key)
    {
        return redisTemplate.opsForList().range(key, 0, -1);
    }

    /**
     * 缓存Set
     *
     * @param key 缓存键值
     * @param dataSet 缓存的数据
     * @return 缓存数据的对象
     */
    public <T> BoundSetOperations<String, T> setCacheSet(final String key, final Set<T> dataSet)
    {
        BoundSetOperations<String, T> setOperation = redisTemplate.boundSetOps(key);
        Iterator<T> it = dataSet.iterator();
        while (it.hasNext())
        {
            setOperation.add(it.next());
        }
        return setOperation;
    }

    /**
     * 获得缓存的set
     *
     * @param key
     * @return
     */
    public <T> Set<T> getCacheSet(final String key)
    {
        return redisTemplate.opsForSet().members(key);
    }

    /**
     * 缓存Map
     *
     * @param key
     * @param dataMap
     */
    public <T> void setCacheMap(final String key, final Map<String, T> dataMap)
    {
        if (dataMap != null) {
            redisTemplate.opsForHash().putAll(key, dataMap);
        }
    }

    /**
     * 获得缓存的Map
     *
     * @param key
     * @return
     */
    public <T> Map<String, T> getCacheMap(final String key)
    {
        return redisTemplate.opsForHash().entries(key);
    }

    /**
     * 往Hash中存入数据
     *
     * @param key Redis键
     * @param hKey Hash键
     * @param value 值
     */
    public <T> void setCacheMapValue(final String key, final String hKey, final T value)
    {
        redisTemplate.opsForHash().put(key, hKey, value);
    }

    /**
     * 获取Hash中的数据
     *
     * @param key Redis键
     * @param hKey Hash键
     * @return Hash中的对象
     */
    public <T> T getCacheMapValue(final String key, final String hKey)
    {
        HashOperations<String, String, T> opsForHash = redisTemplate.opsForHash();
        return opsForHash.get(key, hKey);
    }

    /**
     * 获取多个Hash中的数据
     *
     * @param key Redis键
     * @param hKeys Hash键集合
     * @return Hash对象集合
     */
    public <T> List<T> getMultiCacheMapValue(final String key, final Collection<Object> hKeys)
    {
        return redisTemplate.opsForHash().multiGet(key, hKeys);
    }

    /**
     * 删除Hash中的某条数据
     *
     * @param key Redis键
     * @param hKey Hash键
     * @return 是否成功
     */
    public boolean deleteCacheMapValue(final String key, final String hKey)
    {
        return redisTemplate.opsForHash().delete(key, hKey) > 0;
    }

    /**
     * 获得缓存的基本对象列表
     *
     * @param pattern 字符串前缀
     * @return 对象列表
     */
    public Set<String> keys(final String pattern)
    {
        return (Set<String>) redisTemplate.execute((RedisCallback<Set<String>>) connection -> {
            Cursor<byte[]> cursor = connection.scan(ScanOptions.scanOptions().match(pattern).count(1000).build());
            Set<String> keys = new HashSet<>();
            if (cursor.hasNext()) {
                keys.add(new String(cursor.next()));
            }
            return keys;
        });
    }

    /**
     * 删除缓存
     *
     * @param pattern 字符串前缀
     * @return 对象列表
     */
    public void delete(final String pattern)
    {
        Set<String> keys = new HashSet<>();
        ScanOptions options = ScanOptions.scanOptions().match(pattern).build();
        Cursor<byte[]> cursor = redisTemplate.getConnectionFactory().getConnection().scan(options);

        while (cursor.hasNext()) {
            keys.add(new String(cursor.next()));
        }

// 分批删除,避免一次删除太多 key 导致阻塞
        List<List<String>> partitionedKeys = ListUtils.partition(new ArrayList<>(keys), 500);

        for (List<String> keyBatch : partitionedKeys) {
            redisTemplate.delete(keyBatch);
        }
    }

}