【fasterxml】json 工具类

直接贴代码，方便下次使用。

/**
 * json 工具类
 * <p>
 * Created by xlch at 2018/6/26
 */
public class JsonUtil {


    private JsonUtil() {

    }

    private static final Logger LOGGER = LoggerFactory.getLogger(JsonUtil.class);

    private static final ObjectMapper mapper = new ObjectMapper();


    static {
        // 序列化时 是否包含 null 字段：不包含
        mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
        //反序列化时是否忽略 不存在的属性值：忽略
        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        // 下划线转为驼峰
        mapper.setPropertyNamingStrategy(PropertyNamingStrategy.LOWER_CAMEL_CASE);

    }


    public  static <T> T json2Object(String source, Class<T> classType) {
        try {
            return mapper.readValue(source, classType);
        } catch (IOException e) {
            LOGGER.debug("exception is ", e);
            throw new VastioException("json 读取出错");
        }
    }

    public static <T> List<T> json2ObjectList(String source, Class<T> classType) {
        JavaType javaType = mapper.getTypeFactory().constructParametricType(List.class, classType);
        try {
            return mapper.readValue(source, javaType);
        } catch (IOException e) {
            LOGGER.debug("exception is ", e);
            throw new VastioException("json list 读取出错");
        }
    }

    public static <T> String objects2Json(T source) {
        try {
            return mapper.writeValueAsString(source);
        } catch (JsonProcessingException e) {
            LOGGER.debug("exception is {}", e);
            throw new VastioException("json 写入出错");
        }
    }
}