SpringBoot项目中Redis对java8时间的序列化和反序列化

SpringBoot项目中Redis对java8时间的序列化和反序列化

1、第一种方法是在属性上面为需要序列化的属性加注解，这种方式虽然可用，但是非常繁琐。有时候可能会忘记。

@JsonFormat( pattern="yyyy-MM-dd HH:mm:ss",timezone = "GMT+8")
@JsonDeserialize(using = LocalDateTimeDeserializer.class)
@JsonSerialize(using = LocalDateTimeSerializer.class)
private LocalDateTime createTime;
@JsonFormat( pattern="yyyy-MM-dd HH:mm:ss",timezone = "GMT+8")
@JsonDeserialize(using = LocalDateTimeDeserializer.class)
@JsonSerialize(using = LocalDateTimeSerializer.class)
private LocalDateTime updateTime;

2、弄一个统一配置类如下，让GenericJackson2JsonRedisSerializer 支持java8 time的的序列化和反序列化

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Lazy;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.cache.RedisCacheWriter;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.GenericToStringSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext;

@Configuration
public class RedisConfig {

	@SuppressWarnings({ "unchecked", "rawtypes" })
	@Bean("redisTemplate")
	public RedisTemplate redisTemplate(@Lazy RedisConnectionFactory connectionFactory) {
		RedisTemplate redis = new RedisTemplate();

		GenericToStringSerializer<String> keySerializer = new GenericToStringSerializer<>(String.class);
		redis.setKeySerializer(keySerializer);
		redis.setHashKeySerializer(keySerializer);

		//GenericJackson2JsonRedisSerializer valueSerializer  = new GenericJackson2JsonRedisSerializer();
		GenericJackson2JsonRedisSerializerEx valueSerializer = new GenericJackson2JsonRedisSerializerEx();
		redis.setValueSerializer(valueSerializer);
		redis.setHashValueSerializer(valueSerializer);

		redis.setConnectionFactory(connectionFactory);
		return redis;
	}
}

2、本想继承GenericJackson2JsonRedisSerializer ,但是里面的属性是私有的，对继承不友好。简单粗暴，直接复制一份进行扩展

/*
 * Copyright 2015-2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonTypeInfo.As;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectMapper.DefaultTyping;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.databind.ser.SerializerFactory;
import com.fasterxml.jackson.databind.ser.std.StdSerializer;
import org.springframework.cache.support.NullValue;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.SerializationException;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

import java.io.IOException;

/**
 * Generic Jackson 2-based {@link RedisSerializer} that maps {@link Object objects} to JSON using dynamic typing.
 *
 * @author Christoph Strobl
 * @author Mark Paluch
 * @author Mao Shuai
 * @since 1.6
 */
public class GenericJackson2JsonRedisSerializerEx implements RedisSerializer<Object> {

    private final ObjectMapper mapper;

    /**
     * Creates {@link GenericJackson2JsonRedisSerializerEx} and configures {@link ObjectMapper} for default typing.
     */
    public GenericJackson2JsonRedisSerializerEx() {
        this((String) null);
    }

    /**
     * Creates {@link GenericJackson2JsonRedisSerializerEx} and configures {@link ObjectMapper} for default typing using the
     * given {@literal name}. In case of an {@literal empty} or {@literal null} String the default
     * {@link JsonTypeInfo.Id#CLASS} will be used.
     *
     * @param classPropertyTypeName Name of the JSON property holding type information. Can be {@literal null}.
     */
    public GenericJackson2JsonRedisSerializerEx(@Nullable String classPropertyTypeName) {

        this(new ObjectMapper());

        /** 处理java8 Time */
        mapper.registerModule(new CustomJavaTimeModule());
        
        // simply setting {@code mapper.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS)} does not help here since we need
        // the type hint embedded for deserialization using the default typing feature.
        registerNullValueSerializer(mapper, classPropertyTypeName);

        if (StringUtils.hasText(classPropertyTypeName)) {
            mapper.enableDefaultTypingAsProperty(DefaultTyping.NON_FINAL, classPropertyTypeName);
        } else {
            mapper.enableDefaultTyping(DefaultTyping.NON_FINAL, As.PROPERTY);
        }
    }

    /**
     * Setting a custom-configured {@link ObjectMapper} is one way to take further control of the JSON serialization
     * process. For example, an extended {@link SerializerFactory} can be configured that provides custom serializers for
     * specific types.
     *
     * @param mapper must not be {@literal null}.
     */
    public GenericJackson2JsonRedisSerializerEx(ObjectMapper mapper) {

        Assert.notNull(mapper, "ObjectMapper must not be null!");
        this.mapper = mapper;
    }

    /**
     * Register {@link NullValueSerializer} in the given {@link ObjectMapper} with an optional
     * {@code classPropertyTypeName}. This method should be called by code that customizes
     * {@link GenericJackson2JsonRedisSerializerEx} by providing an external {@link ObjectMapper}.
     *
     * @param objectMapper the object mapper to customize.
     * @param classPropertyTypeName name of the type property. Defaults to {@code @class} if {@literal null}/empty.
     * @since 2.2
     */
    public static void registerNullValueSerializer(ObjectMapper objectMapper, @Nullable String classPropertyTypeName) {

        // simply setting {@code mapper.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS)} does not help here since we need
        // the type hint embedded for deserialization using the default typing feature.
        objectMapper.registerModule(new SimpleModule().addSerializer(new NullValueSerializer(classPropertyTypeName)));
    }

    /*
     * (non-Javadoc)
     * @see org.springframework.data.redis.serializer.RedisSerializer#serialize(java.lang.Object)
     */
    @Override
    public byte[] serialize(@Nullable Object source) throws SerializationException {

        if (source == null) {
            return new byte[0];
        }

        try {
            return mapper.writeValueAsBytes(source);
        } catch (JsonProcessingException e) {
            throw new SerializationException("Could not write JSON: " + e.getMessage(), e);
        }
    }

    /*
     * (non-Javadoc)
     * @see org.springframework.data.redis.serializer.RedisSerializer#deserialize(byte[])
     */
    @Override
    public Object deserialize(@Nullable byte[] source) throws SerializationException {
        return deserialize(source, Object.class);
    }

    /**
     * @param source can be {@literal null}.
     * @param type must not be {@literal null}.
     * @return {@literal null} for empty source.
     * @throws SerializationException
     */
    @Nullable
    public <T> T deserialize(@Nullable byte[] source, Class<T> type) throws SerializationException {

        Assert.notNull(type,
                "Deserialization type must not be null! Please provide Object.class to make use of Jackson2 default typing.");

        if (isEmpty(source)) {
            return null;
        }

        try {
            return mapper.readValue(source, type);
        } catch (Exception ex) {
            throw new SerializationException("Could not read JSON: " + ex.getMessage(), ex);
        }
    }

    /**
     * {@link StdSerializer} adding class information required by default typing. This allows de-/serialization of
     * {@link NullValue}.
     *
     * @author Christoph Strobl
     * @since 1.8
     */
    private static class NullValueSerializer extends StdSerializer<NullValue> {

        private static final long serialVersionUID = 1999052150548658808L;
        private final String classIdentifier;

        /**
         * @param classIdentifier can be {@literal null} and will be defaulted to {@code @class}.
         */
        NullValueSerializer(@Nullable String classIdentifier) {

            super(NullValue.class);
            this.classIdentifier = StringUtils.hasText(classIdentifier) ? classIdentifier : "@class";
        }

        /*
         * (non-Javadoc)
         * @see com.fasterxml.jackson.databind.ser.std.StdSerializer#serialize(java.lang.Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)
         */
        @Override
        public void serialize(NullValue value, JsonGenerator jgen, SerializerProvider provider)
                throws IOException {

            jgen.writeStartObject();
            jgen.writeStringField(classIdentifier, NullValue.class.getName());
            jgen.writeEndObject();
        }
    }

    static boolean isEmpty(@Nullable byte[] data) {
        return (data == null || data.length == 0);
    }
}

直接在GenericJackson2JsonRedisSerializerEx(@Nullable String classPropertyTypeName)方法中加入
mapper.registerModule(new CustomJavaTimeModule());即可，CustomJavaTimeModule类在上一篇配置jackson对java8时间的支持的里面

小尾巴~~
只要有积累，就会有进步