Dev-009、jackson通用工具类

1、通用工具类

@Slf4j
@Component
public class JacksonUtils{
    private final ObjectMapper mapper = new ObjectMapper();

    /**
     * json字符串转成list
     *
     * @param jsonString
     * @param cls
     * @return
     */
    public <T> List<T> jsonToList(@NonNull String jsonString, Class<T> cls) {
        try {
            return mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES,false).readValue(jsonString, getCollectionType(List.class, cls));
        } catch (JsonProcessingException e) {
            String className = cls.getSimpleName();
            log.error(" parse json {} to class {} error：{}", jsonString, className, e.getMessage());
        }
        return null;
    }

    /**
     *  json字符串转成 java对象
     * @param jsonString
     * @param cls
     * @param <T>
     * @return
     */
    public <T> T jsonToJava(@NonNull String jsonString, Class<T> cls){
        try {
            return mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES,false).readValue(jsonString,cls);
        } catch (JsonProcessingException e) {
            String className = cls.getSimpleName();
            log.error(" parse json {} to class {} error：{}", jsonString, className,  e.getMessage());
        }
        return null;
    }

    /**
     *  java对象转成 json字符串
     * @param cls
     * @return
     */
    public <T> String javaToJson(@NonNull T cls){
        try {
            return mapper.writerWithDefaultPrettyPrinter().writeValueAsString(cls);
        } catch (JsonProcessingException e) {
            log.error(" parse class {} to json error：{}", cls, e.getMessage());
        }
        return null;
    }

    /**
     * 获取泛型的Collection Type
     *
     * @param collectionClass 泛型的Collection
     * @param elementClasses  实体bean
     * @return JavaType Java类型
     */
    private  JavaType getCollectionType(Class<?> collectionClass, Class<?>... elementClasses) {
        return mapper.getTypeFactory().constructParametricType(collectionClass, elementClasses);
    }
}

2、 解决JSON中存在大字字母而造成反序列化失败问题

@Data
public class ParmsVo implements Serializable{

    private static final long serialVersionUID = 1L;

    @JsonProperty("Value")
    private T value;

    @JsonProperty("Type")
    private int type;

    @JsonProperty("Name")
    private String name;
}

@JsonProperty：用于实体类的属性上，在反序列化的时候给属性重命名