Fastjson技术内幕

关于循环引用的解决办法的问题：
1、transient和hibernate注解同时使用时报错；
2、使用@JSONField时可以，但实际使用中会经常会需要显示部门的上级部门的，用@JSONField设置不做序列化后，在界面上无法显示上级部门，用jackjson时是不会报错的，只是会把上级的上级的上级……都序列化出来而已，fastjson能不能在加入一个Feature，可以设置循环引用的深度呢？另外，还有一种情况，用户关联了部门，部门关联了自己(上级部门)，jackjson会把用户的部门和部门关联的所有上级都序列化出来了，fastjson如果加入的循环引用深度的Feature，就可以不需要加载部门的上级……了。不知目前fastjson能否做到这点。如果不能，强烈要求加入这个功能。
关于打印空值问题：
3、WriteMapNullValue是全局的设置，但是我有特殊属性是就算是空值也需要打印出来的。比如一个用户列表界面，用户关联了部门，如果部门是NULL，则界面需要“{}”这样的值，否则界面报错，fastjson好像也没有提供这样的功能。

我之前提过这些问题和建议的，不知现在解决没？现在就是问题2和3没有找到解决办法是我还没从jackjson转到fastjson的原因。希望温少可以帮我解决下。

执行:Status o=JSON.parseObject(st,Status.class);报以下错误
产生的异常
com.alibaba.fastjson.JSONException: class not has default constructor : weibo4android.Status



st参数的值为的值为

{"bmiddle_pic":"","createdAt":1312816303000,"favorited":false,"id":3344256320529927,"inReplyToScreenName":"","inReplyToStatusId":-1,"inReplyToUserId":-1,"latitude":-1,"longitude":-1,"mid":"3344256320529927","original_pic":"","rateLimitLimit":-1,"rateLimitRemaining":-1,"rateLimitReset":-1,"retweet":true,"retweetDetails":{"rateLimitLimit":-1,"rateLimitRemaining":-1,"rateLimitReset":-1,"retweetId":0,"retweetingUser":{"favouritesCount":0,"followersCount":0,"following":false,"friendsCount":0,"geoEnabled":false,"id":0,"notificationEnabled":false,"notifications":false,"protected":false,"rateLimitLimit":-1,"rateLimitRemaining":-1,"rateLimitReset":-1,"statusFavorited":false,"statusId":-1,"statusInReplyToStatusId":-1,"statusInReplyToUserId":-1,"statusTruncated":false,"statusesCount":0,"utcOffset":0,"verified":false}},"retweeted_status":{"bmiddle_pic":"http://ww3.sinaimg.cn/bmiddle/62c76a9dtw1djxwakxs7lj.jpg","createdAt":1312767831000,"favorited":false,"id":3344053013979515,"inReplyToScreenName":"","inReplyToStatusId":-1,"inReplyToUserId":-1,"latitude":-1,"longitude":-1,"mid":"3344053013979515","original_pic":"http://ww3.sinaimg.cn/large/62c76a9dtw1djxwakxs7lj.jpg","rateLimitLimit":-1,"rateLimitRemaining":-1,"rateLimitReset":-1,"retweet":false,"source":"<a href=\"http://weibo.com\" rel=\"nofollow\">新浪微博</a>","text":"“中国人每日辛勤劳作生产产品给美国人用，而我们给他们一些纸片。当他们想用这些纸片时，却发现这纸片不能达到他们想要的目的。”——在谈及美国大量借债行为时，巴菲特在2009年股东大会上如是说","thumbnail_pic":"http://ww3.sinaimg.cn/thumbnail/62c76a9dtw1djxwakxs7lj.jpg","truncated":false,"user":{"createdAt":1256832000000,"description":"《环球企业家》官方微博：关于中国和全球商业的严肃口水","favouritesCount":134,"followersCount":476617,"following":false,"friendsCount":555,"gender":"m","geoEnabled":false,"id":1657236125,"location":"北京 东城区","name":"环球企业家杂志","notificationEnabled":false,"notifications":false,"profileBackgroundColor":"","profileBackgroundImageUrl":"","profileBackgroundTile":"","profileImageURL":"http://tp2.sinaimg.cn/1657236125/50/5606978745/1","profileLinkColor":"","profileSidebarBorderColor":"","profileSidebarFillColor":"","profileTextColor":"","protected":false,"rateLimitLimit":-1,"rateLimitRemaining":-1,"rateLimitReset":-1,"screenName":"环球企业家杂志","statusFavorited":false,"statusId":-1,"statusInReplyToStatusId":-1,"statusInReplyToUserId":-1,"statusTruncated":false,"statusesCount":5247,"timeZone":"","uRL":"http://www.gemag.com.cn","userDomain":"gemag","utcOffset":-1,"verified":true}},"source":"<a href=\"http://weibo.com\" rel=\"nofollow\">新浪微博</a>","text":"//@王兆春 我党为什么把那么多的老百姓劳动成果换成绿纸？还不给劳动人民呢？真是奇怪！","thumbnail_pic":"","truncated":false,"user":{"createdAt":1256832000000,"description":"《环球企业家》官方微博：关于中国和全球商业的严肃口水","favouritesCount":134,"followersCount":476617,"following":false,"friendsCount":555,"gender":"m","geoEnabled":false,"id":1657236125,"location":"北京 东城区","name":"环球企业家杂志","notificationEnabled":false,"notifications":false,"profileBackgroundColor":"","profileBackgroundImageUrl":"","profileBackgroundTile":"","profileImageURL":"http://tp2.sinaimg.cn/1657236125/50/5606978745/1","profileLinkColor":"","profileSidebarBorderColor":"","profileSidebarFillColor":"","profileTextColor":"","protected":false,"rateLimitLimit":-1,"rateLimitRemaining":-1,"rateLimitReset":-1,"screenName":"环球企业家杂志","statusFavorited":false,"statusId":-1,"statusInReplyToStatusId":-1,"statusInReplyToUserId":-1,"statusTruncated":false,"statusesCount":5247,"timeZone":"","uRL":"http://www.gemag.com.cn","userDomain":"gemag","utcOffset":-1,"verified":true}}

问题2还没有，这个不难，在1.1.3中实现好了。
问题3已经实现，在字段上可以使用@JSONField设置WriteMapNullValue属性

这个是因为weibo4android.Status这个类没有缺省构造函数，所以无法反序列化。

Status有构造函数,是否要默认符合fastjson指定格式的构造函数,我现在把Status这个类上传到附件中!

楼上的bean类,包含了非java自定义类型,这种bean设计不应该被推荐,复杂的项目容易引起问题

Status类还存在循环引用

我想知道怎么和spring整合起来，能搞个插件集成下吧？和jackson一样内置到spring中

文档几乎没有。。我就想知道，对于一个实体，如果属性为null，在序列化后，我仍希望全部序列化所有字段，为null的字段则序列化为空，而不是不输出。这该怎么设置？

还要补充下文档哦，温少，官方上面很多是以前版本的例子和说明。