1、XStream介绍
XStream是一个简单的基于Java库，Java对象序列化到XML，反之亦然(即：可以轻易的将Java对象和xml文档相互转换)。
2、XStream特点
- Ease of use. A high level facade is supplied that simplifies common use cases.
- No mappings required. Most objects can be serialized without need for specifying mappings.
- Performance. Speed and low memory footprint are a crucial part of the design, making it suitable for large object graphs or systems with high message throughput.
- Clean XML. No information is duplicated that can be obtained via reflection. This results in XML that is easier to read for humans and more compact than native Java serialization.
- Requires no modifications to objects. Serializes internal fields, including private and final. Supports non-public and inner classes. Classes are not required to have default constructor.
- Full object graph support. Duplicate references encountered in the object-model will be maintained. Supports circular references.
- Integrates with other XML APIs. By implementing an interface, XStream can serialize directly to/from any tree structure (not just XML).
- Customizable conversion strategies. Strategies can be registered allowing customization of how particular types are represented as XML.
- Security framework. Fine-control about the unmarshalled types to prevent security issues with manipulated input.
- Error messages. When an exception occurs due to malformed XML, detailed diagnostics are provided to help isolate and fix the problem.
- Alternative output format. The modular design allows other output formats. XStream ships currently with JSON support and morphing.
使用方便 - XStream的API提供了一个高层次外观，以简化常用的用例。
无需创建映射 - XStream的API提供了默认的映射大部分对象序列化。
性能 - XStream快速和低内存占用，适合于大对象图或系统。
干净的XML - XStream创建一个干净和紧凑XML结果，这很容易阅读。
不需要修改对象 - XStream可序列化的内部字段，如私有和最终字段，支持非公有制和内部类。默认构造函数不是强制性的要求。
完整对象图支持 - XStream允许保持在对象模型中遇到的重复引用，并支持循环引用。
可自定义的转换策略 - 定制策略可以允许特定类型的定制被表示为XML的注册。
安全框架 - XStream提供了一个公平控制有关解组的类型，以防止操纵输入安全问题。
错误消息 - 出现异常是由于格式不正确的XML时，XStream抛出一个统一的例外，提供了详细的诊断，以解决这个问题。
另一种输出格式 - XStream支持其它的输出格式，如JSON。
3、XStream常见的用途
Transport
Persistence
Configuration
Unit Tests
传输
持久化
配置
单元测试
Known Limitations
If using the enhanced mode, XStream can re-instantiate classes that do not have a default constructor. However, if using a different JVM like an old JRockit version, a JDK 1.4 or you have restrictions because of a SecurityManager, a default constructor is required.
The enhanced mode is also necessary to restore final fields for any JDK < 1.5. This implies deserialization of instances of an inner class.
Auto-detection of annotations may cause race conditions. Preprocessing annotations is safe though.