SpringBoot自定义枚举序列化方式

2022-06-22 23:34:12 669

在平常web开发中, 或多或少的会使用到枚举类型

但是springboot对枚举的序列化并不太符合实际开发需求

比如

public enum MerchantStatusEnum {
    NORMAL(100, "正常"),
    BAN(200, "封禁");


    private final Integer type;
    private final String name;

    MerchantStatusEnum(Integer type, String name) {
        this.name = name;
        this.type = type;
    }
}

序列化后是这样的

{
    "status": "NORMAL"
}

而且使用枚举接受请求参数时, 字段也必须采用如上格式, 对前端不太便利.

所以自定义枚举的序列化器进行自定义的序列化

改造如下

定义接口

public interface TypeEnum {
    /**
     * 由枚举实现
     *
     * @return 枚举类的type字段
     */
    Integer getType();

    /**
     * 由枚举实现
     *
     * @return 枚举类的name字段
     */
    String getName();
}

实现接口, 标记此枚举使用自定义的序列化方式

@Getter
public enum MerchantStatusEnum implements TypeEnum {
    /**
     * 正常
     */
    NORMAL(100, "正常"),
    /**
     * 封禁
     */
    BAN(200, "封禁");


    @EnumValue
    private final Integer type;


    private final String name;

    MerchantStatusEnum(Integer type, String name) {
        this.name = name;
        this.type = type;
    }
}

type到枚举的映射方法

public class EnumUtil {

    private static final Map<Class<? extends Enum<?>>, Map<?, ? extends Enum<? extends TypeEnum>>> CLASS_ENUM_MAP =
            new ConcurrentHashMap<>(16);

    @SuppressWarnings("unchecked")
    public static <E extends Enum<E> & TypeEnum> E match(Class<E> enumClass, Integer type) {
        var enumMap = CLASS_ENUM_MAP.get(enumClass);
        if (Objects.isNull(enumMap)) {
            var unmodifiableMap = Arrays.stream(enumClass.getEnumConstants())
                    .collect(Collectors.toUnmodifiableMap(TypeEnum::getType, v -> v));
            CLASS_ENUM_MAP.putIfAbsent(enumClass, unmodifiableMap);
            return unmodifiableMap.get(type);
        }
        return (E) enumMap.get(type);
    }
}

自定义反序列化类

public class TypeEnumDeserializer extends StdDeserializer<TypeEnum> implements ContextualDeserializer {

    public TypeEnumDeserializer() {
        super((JavaType) null);
    }

    public TypeEnumDeserializer(JavaType valueType) {
        super(valueType);
    }

    @Override
    public JsonDeserializer<?> createContextual(DeserializationContext ctxt, BeanProperty property) {
        return new TypeEnumDeserializer(property.getType());
    }

    @Override
    @SuppressWarnings("all")
    public TypeEnum deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
        return (TypeEnum) EnumUtil.match((Class) _valueClass, p.getIntValue());
    }
}

注册到springboot中

    
    
@Configuration
@Slf4j
public class WebMvcConfig implements WebMvcConfigurer {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        var stringHttpMessageConverter = new StringHttpMessageConverter(StandardCharsets.UTF_8);
        var converter = new MappingJackson2HttpMessageConverter();

        converter.setObjectMapper(objectMapperForWebConvert());
        converters.add(0, stringHttpMessageConverter);
        converters.add(0, converter);
    }
    
    
    public ObjectMapper objectMapperForWebConvert() {
        var om = new ObjectMapper();
        om.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

        var sm = new SimpleModule();
        //自定义查找规则
        sm.setDeserializers(new SimpleDeserializers() {
            @Override
            public JsonDeserializer<?> findEnumDeserializer(Class<?> type, DeserializationConfig config,
                                                            BeanDescription beanDesc) throws JsonMappingException {
                var enumDeserializer = super.findEnumDeserializer(type, config, beanDesc);
                if (enumDeserializer != null) {
                    return enumDeserializer;
                }
                //遍历枚举实现的接口, 查找反序列化器
                for (var typeInterface : type.getInterfaces()) {
                    enumDeserializer = this._classMappings.get(new ClassKey(typeInterface));
                    if (enumDeserializer != null) {
                        return enumDeserializer;
                    }
                }
                return null;
            }
        });
        sm.addDeserializer(TypeEnum.class, new TypeEnumDeserializer());

        sm.addSerializer(TypeEnum.class, new JsonSerializer<>() {
            @Override
            public void serialize(TypeEnum value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
                gen.writeStartObject();
                gen.writeNumberField("type", value.getType());
                gen.writeStringField("name", value.getName());
                gen.writeEndObject();
            }

            @Override
            public void serializeWithType(TypeEnum value, JsonGenerator gen, SerializerProvider serializers,
                                          TypeSerializer typeSer) throws IOException {
                var typeIdDef = typeSer.writeTypePrefix(gen, typeSer.typeId(value, JsonToken.VALUE_STRING));
                serialize(value, gen, serializers);
                typeSer.writeTypeSuffix(gen, typeIdDef);
            }
        });
        om.registerModule(sm);

        return om;
    }
}

自此, 前端可以传递type值即可映射到枚举

{
    "status": 100
}

后端的响应

{
    "status": {
        "type": 100,
        "name": "正常"
    }
}

• java
• springboot