Jackson：根据属性值，自定义改变属性值进行序列化和反序列化

刺骨的言语ヽ痛彻心扉 2024-03-25 20:30 80阅读 0赞

**根据属性值，自定义改变属性值进行序列化**

JsonSerialize用于序列化场景，被此注解修饰的字段或者get方法会被用于序列化，并且using属性指定了执行序列化操作的类；

执行序列化操作的类，需要继承自JsonSerializer，如下所示，TowardEnumSerializer的作用是将TowardEnum类型转成String类型：

import com.baomidou.mybatisplus.annotation.EnumValue;
    import lombok.AllArgsConstructor;
    import lombok.Getter;
    
    import java.util.Objects;
    import java.util.stream.Stream;
    
    @Getter
    @AllArgsConstructor
    public enum TowardEnum {
    
        /**
         * 未知
         */
        UNKNOWN(0, "未知"),
        /**
         * 东
         */
        NORTH(1,"东"),
        /**
         * 南
         */
        SOUTH(2,"南"),
        /**
         * 西
         */
        EAST(3,"西"),
        /**
         * 北
         */
        WEST(4,"北"),
        /**
         * 东南
         */
        SOUTHEAST(5,"东南"),
        /**
         * 西南
         */
        SOUTHWEST(6,"西南"),
        /**
         * 东北
         */
        NORTHEAST(7,"东北"),
        /**
         * 西北
         */
        NORTHWEST(8,"西北");
    
        @EnumValue
        private final Integer id;
        private final String desc;
    
        public static String getToward(Integer id) {
            return Arrays.stream(TowardEnum.values()).filter(e -> Objects.equals(e.id, id)).map(e -> e.desc).findFirst().orElse("");
        }
    
    }

import cn.gcfc.admin.enums.house.TowardEnum;
    import com.fasterxml.jackson.core.JsonGenerator;
    import com.fasterxml.jackson.databind.JsonSerializer;
    import com.fasterxml.jackson.databind.SerializerProvider;
    
    public class TowardEnumSerializer extends JsonSerializer<TowardEnum> {
    
        @Override
        public void serialize(TowardEnum towardEnum, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
            jsonGenerator.writeString(towardEnum.getDesc());
        }
    }

@ApiModel(value = "房间信息")
    public class RoomVO {
    
        @JsonSerialize(using = TowardEnumSerializer.class)
        @ApiModelProperty(value = "房间朝向")
        private TowardEnum toward;
    }

**根据属性值，自定义改变属性值进行反序列化**

执行反序列化操作的类需要继承自JsonDeserializer，如下所示，Long2DateDeserialize的作用是将Long类型转成startTime字段对应的Date类型：

public class Long2DateDeserialize extends JsonDeserializer<Date> {
    
            @Override
            public Date deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException {
    
                if(null!=p && null!=ctxt && p.getLongValue()>0L ) {
                    return new Date(p.getLongValue());
                }
    
                return null;
            }
        }

DTO

public class RoomDTO {
    
        @JsonDeserialize(using = Long2DateDeserialize.class)
        private Data startTime;
    }