Android中XStream基础使用

• 集成XStream

    implementation 'com.thoughtworks.xstream:xstream:1.4.19'

• 基础使用

  1.定义实体类

      @XStreamAlias("Document")
      data class WPMLDocument(
          @XStreamAlias("wpml:missionConfig")
          val missionConfig: WPMLMissionConfig,
          @XStreamAlias("Folder")
          val folder: WPMLFolder
      )
  

  2.注解使用

  @XStreamAlias:定义根节点别名与属性别名
  
  @XStreamOmitField:忽略该属性
  
  @XStreamAsAttribute:声明命名空间
  

  3.序列化

  val xStream = XmlUtf8XStream(
          reflectionProvider = PureJavaReflectionProvider(
              FieldDictionary(PartialSeqFieldKeySorter())
          )
      )
      xStream.processAnnotations(WPMLRootElement::class.java)
      return xStream.toXML(this)
  

  4.反序列化

      Class<?>[] classes = new Class[] { TestBody.class};
      val xStream = XStream()
      xStream.allowTypes(classes)//白名单
      xStream.processAnnotations(classes)//开启注解
      val wpml = xStream.fromXML(wpmlFile)
  

• 疑难问题

  • 按顺序序列化

  @XMLSequence
  

  • 反序列化安全问题：

  com.thoughtworks.xstream.security.ForbiddenClassException com.thoughtworks.xstream
  

  解决方法：添加白名单

  Class<?>[] classes = new Class[] { TestBody.class};
  xStream.allowTypes(classes);
  

  • 反序列化注解不识别：

  com.thoughtworks.xstream.mapper.CannotResolveClassException: xxx
  

  解决方法：反序列化手动开启注解

  xStream.processAnnotations(classes)
  

  • xml文件新增版本号

      class XmlUtf8XStream(version:String="1.0",encoding:String = "UTF-8",reflectionProvider:ReflectionProvider):XStream(reflectionProvider) {
      
          private var version:String
          private var encoding:String
      
          init {
              this.version = version
              this.encoding = encoding
          }
      
          private fun getDeclaration():String {
              return "<?xml version=\"" + this.version + "\" encoding=\"" + this.encoding + "\"?>\n"
          }
      
          override fun toXML(obj: Any?, out: OutputStream?) {
              val dec = getDeclaration()
              val bytesOfDec = dec.toByteArray(charset("UTF-8"))
              out?.write(bytesOfDec)
              super.toXML(obj, out)
          }
      
          override fun toXML(obj: Any?, out: Writer?) {
              out?.write(getDeclaration())
              super.toXML(obj, out)
          }
  }