XStream arrayList 与 XML 之间的往来 [英] XStream arrayList to and from XML
问题描述
我目前不知道问题出在哪里.第一次使用 xml,我在将 ArrayList 放入 xml 文件并从中取出时遇到了一些问题.
I do not know where the problem is at the moment. First time using xml, and I got some problems with putting ArrayList in xml file and taking it from it.
我被发现了,我尝试用同样的方法:如何使用 XStream 将对象列表转换为 XML 文档
I was found this and I tried to do it same way: How to convert List of Object to XML doc using XStream
但不幸的是我失败了.这是我到目前为止所拥有的:保存 ArrayList 的类:
but unfortunately I failed. Here what I have so far: Class that holds ArrayList:
public class ElbowList{
private ArrayList<Elbow> elbows = new ArrayList<>();
public ElbowList(){
elbows = new ArrayList<Elbow>();
}
public void setElbows(ArrayList<Elbow> elbows){
this.elbows.clear();
this.elbows = elbows;
}
public ArrayList<Elbow> getElbows() {
return elbows;
}
public void add(Elbow elbow){
elbows.add(elbow);
}
}
保存到 XML:
MainFrame mainFrame = (MainFrame) SwingUtilities.getWindowAncestor(SetupPanel.this);
ElbowList elbowList = (ElbowList) mainFrame.getObjects().get(2); //get ElbowList object
XStream xstream = new XStream();
xstream.alias("elbow", Elbow.class);
xstream.alias("elbows", ElbowList.class);
xstream.addImplicitCollection(ElbowList.class, "elbows", Elbow.class);
String xml = xstream.toXML(elbowList.getElbows());
System.out.println(xml);
try {
PrintWriter out = new PrintWriter("Save.xml");
out.println(xml);
out.close();
} catch (FileNotFoundException ex) {
Logger.getLogger(SetupPanel.class.getName()).log(Level.SEVERE, null, ex);
}
上面的那个实际上似乎工作正常.加载 XML 文件,在那里我得到了一个异常调用:
And that one above actually seems to work correctly. Load XML file, there is where I got an exception call:
try {
XStream xstream = new XStream();
FileReader reader = new FileReader("Save.xml");
MainFrame mainFrame = (MainFrame) SwingUtilities.getWindowAncestor(SetupPanel.this);
ElbowList elbowList = (ElbowList) mainFrame.getObjects().get(2);
elbowList.setElbows((ArrayList<Elbow>) xstream.fromXML(reader));//exception occurs here
SpacePanel spacePanel = (SpacePanel) mainFrame.getObjects().get(1);
spacePanel.repaint();
} catch (IOException ex) {
Logger.getLogger(SetupPanel.class.getName()).log(Level.SEVERE, null, ex);
}
我得到一个例外:
Exception in thread "AWT-EventQueue-0" com.thoughtworks.xstream.converters.ConversionException: elbow : elbow
---- Debugging information ----
message : elbow
cause-exception : com.thoughtworks.xstream.mapper.CannotResolveClassException
cause-message : elbow
class : java.util.ArrayList
required-type : java.util.ArrayList
converter-type : com.thoughtworks.xstream.converters.collections.CollectionConverter
path : /list/elbow
line number : 2
version : 1.4.7
-------------------------------
at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:79)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:79)
at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:65)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:66)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:50)
at com.thoughtworks.xstream.core.TreeUnmarshaller.start(TreeUnmarshaller.java:134)
at com.thoughtworks.xstream.core.AbstractTreeMarshallingStrategy.unmarshal(AbstractTreeMarshallingStrategy.java:32)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:1185)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:1169)
at com.thoughtworks.xstream.XStream.fromXML(XStream.java:1040)
at view.SetupPanel$2.actionPerformed(SetupPanel.java:78)
(...)
我不明白为什么会出现转换异常,对我来说,如果发生异常时涉及到这一行,一切似乎都是正确的.我没有更多的想法是怎么回事,请帮忙.
I dont get why there is an conversion exception, for me everything seems right if it comes to this line when exception occurs. I have no more ideas whats wrong, please help.
推荐答案
您忘记添加
XStream xstream = new XStream();
xstream.alias("elbow", Elbow.class);
xstream.alias("elbows", ElbowList.class);
xstream.addImplicitCollection(ElbowList.class, "elbows", Elbow.class);
加载时也是如此.
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