详解Java如何优雅的实现字典翻译

@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@JacksonAnnotationsInside
@JSONSerialize(using = DictSerializer.class)
public @interface Dict {
​
    
    String dic();
}

@Slf4j
public class DictSerializer extends StdSerializer<Object> implements ContextualSerializer {
​
    private transient String dictCode;
​
    @Override
    public JsonSerializer<?> createContextual(SerializerProvider prov, BeanProperty beanProperty){
        Dict dict = beanProperty.getAnnotation(Dict.class);
        return createContextual(dict.dic());
    }
​
    private JsonSerializer<?> createContextual(String dicCode) {
        DictSerializer serializer = new DictSerializer();
        serializer.setDictCode(dicCode);
        return serializer;
    }
​
    @Override
    public void serialize(Object value, JsonGenerator gen, SerializerProvider provider){
​
        String dictCode = getDictCode();
        if (StrUtil.isBlank(dictCode)) {
            return;
        }
        if (Objects.isNull(value)) {
            return;
        }
        try {
            // 因为序列化是每个对象都需要进行序列话操作，这里为了减少网络IO，使用了 guava 的本地缓存（代码在下面）
            Map<String, String> dictMap = DictionaryConstants.DICTIONARY_CACHE.get(dictCode);
            if (dictMap.containsKey("nullValue")) {
                // 当本地缓存中不存在该类型的字典时，就调用查询方法，并且放入到本地缓存中（代码在下面）
                dictMap = translateDictValue(dictCode);
                DictionaryConstants.DICTIONARY_CACHE.put(dictCode, dictMap);
            }
            // 通过数据字典类型和value获取name
            String label = dictMap.get(value.toString());
            gen.writeObject(value);
            // 在需要转换的字段上添加@Dict注解，注明需要引用的code，后端会在返回值中增加filedName_dictText的key，前端只需要取对应的 filedName_dictText 就可以直接使用
            gen.writeFieldName(gen.getOutputContext().getCurrentName() + DictionaryConstants.DICT_TEXT_SUFFIX);
            gen.writeObject(label);
        } catch (Exception e) {
            log.error("错误信息:{}", e.getMessage(), e);
        }
    }
​
    private String getDictCode() {
        return dictCode;
    }
​
    private void setDictCode(String dictCode) {
        this.dictCode = dictCode;
    }
​
    protected DictSerializer() {
        super(Object.class);
    }
}

private Map<String, String> translateDictValue(String code) {
    if (StrUtil.isBlank(code)) {
      return null;
    }
    // Map<String, String> map = new HashMap<>();
    // map.put("1", "小学生");
    // map.put("2", "初中生");
    // map.put("3", "高中生");
    // map.put("4", "大学生");
  
    // 因为我们公司采用微服务，然后字典模块单独拆分成一个服务，所以这里使用Feign方式调用
    DictionaryFeignClient dictionaryFeign = springUtil.getBean(DictionaryFeignClient.class);
    return dictionaryFeign.dictionary(code);
}

public class DictionaryConstants {
​
    
    public static final String DICT_TEXT_SUFFIX = "_dictText";
​
    public static final LoadingCache<String, Map<String, String>> DICTIONARY_CACHE = CacheBuilder.newBuilder()
            .maximumSize(1000)
            .expireAfterWrite(30, TimeUnit.SECONDS)
            .expireAfterAccess(10, TimeUnit.SECONDS)
            .build(new CacheLoader<String, Map<String, String>>() {
                @Override
                public Map<String, String> load(String key) {
                    Map<String, String> map = new HashMap<>();
                    map.put("nullValue", "nullValue");
                    return map;
                }
            });
}

public class Company {
  private List<Staff> staffs;
}
​
public class Staff {
  private Integer age;
  private String name;
  @Dic(dic = "position")
  private String position;
  
}