Gson is a Java library that can be used to convert Java Objects into their JSON representation. It can also be used to convert a JSON string to an equivalent Java object. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of.
There are a few open-source projects that can convert Java objects to JSON. However, most of them require that you place Java annotations in your classes; something that you can not do if you do not have access to the source-code. Most also do not fully support the use of Java Generics. Gson considers both of these as very important design goals.
Gson Goals
Provide simple toJson() and fromJson() methods to convert Java objects to JSON and vice-versa Allow pre-existing unmodifiable objects to be converted to and from JSON Extensive support of Java Generics Allow custom representations for objects Support arbitrarily complex objects (with deep inheritance hierarchies and extensive use of generic types)
------解决方案-------------------- json是一种轻量级的数据交互格式,json与xml有相同的特性,易于人编写、阅读和机器的解析,而 gson是谷歌提供的一种json解决方案,其内部对json做了很好的封装, 例如:json不支持对关联查询,而gson则可以支持更深层次关联查询; 同时gson的使用比json更加简单。