jackson使用心得记录

一.jackson一般的使用默认的配置：

1.json字符串转化为对应的java类

public static <T> T transferToObj(String jsonString, Class<T> valueType) {
        if (StringUtil.isBlank(jsonString)) {
            throw new IllegalArgumentException(
                    "[Assertion failed] - the object argument must be blank");
        }

        T value = null;
        try {
            ObjectMapper mapper = new ObjectMapper();
            value = mapper.readValue(jsonString, valueType);
        } catch (JsonParseException e) {
            ExceptionUtil.caught(e, "jsonString=[" + jsonString + "]");
        } catch (JsonMappingException e) {
            ExceptionUtil.caught(e, "jsonString=[" + jsonString + "]");
        } catch (IOException e) {
            ExceptionUtil.caught(e, "jsonString=[" + jsonString + "]");
        }

        return value;
    }

2.java类转化为json字符串

public static <T> String transfer2JsonString(T value) {
        ObjectMapper mapper = new ObjectMapper();
        StringWriter sw = new StringWriter();
        JsonGenerator gen;
        try {
            gen = new JsonFactory().createGenerator(sw);
            mapper.writeValue(gen, value);
            gen.close();
        } catch (IOException e) {
            ExceptionUtil.caught(e, "value=[" + value + "]");

        }

        return sw.toString();
    }

二.一些我用到的配置
1.对于json字符串转java对象

......
ObjectMapper mapper = new ObjectMapper();
//在反序列化的时候，如果不识别的字段忽略
mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
//反序列化时候，如果json串中的字段出现String("")或者null的就把java对应属性设置为Null
mapper.configure(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT, true);
value = mapper.readValue(jsonString, valueType);
..........

除了DeserializationFeature，还可以设置SerializationFeature也就是序列化的属性