元素列表中的空條目SimpleXML

Question

我的問題很簡單，但我無法找到它。

我有一個列表類和XML序列化的入門級：

@Root(name = "entries") 
public class List { 

    @ElementList(required = false, entry = "entry", inline = true, empty = true) 
    private List<Entry> entries; 
} 

@Root 
public class Entry { 

    @Element(name = "entry_id", required = true) 
    private long id; 

    @Element(name = "text", required = true) 
    private String Text; 
} 

我試圖解析這個XML，它沒有在列表中的條目：

<entries> 
    <entry /> 
<entries> 

返回以下錯誤：

W/System.err(3335): org.simpleframework.xml.core.ValueRequiredException: Unable to satisfy @org.simpleframework.xml.Element(data=false, name=entry_id, required=true, type=void) on field 'id' private long com.android.apps.model.Entry.id for class com.android.apps.model.Entry at line 2 

我在做什麼錯？ ElementList被設置爲空= true並且必需= false。 有人可以幫忙嗎？

Answer 1

您可以檢查手動空元素：

@Root(name = "entries") 
@Convert(List.ListConverter.class) // Set the converter 
public class List 
{ 
    @ElementList(required = false, entry = "entry", inline = true, empty = true) 
    private java.util.List<Entry> entries; 


    public void add(Entry e) 
    { 
     // Just for testing 
     entries.add(e); 
    } 



    static class ListConverter implements Converter<List> 
    { 
     @Override 
     public List read(InputNode node) throws Exception 
     { 
      List l = new List(); 
      InputNode child = node.getNext("entry"); 

      while(child != null) 
      { 
       if(child.isEmpty() == true) // child is an empty tag 
       { 
        // Do something if entry is empty 
       } 
       else // child is not empty 
       { 
        Entry e = new Persister().read(Entry.class, child); // Let the Serializer read the Object 
        l.add(e); 
       } 

       child = node.getNext("entry"); 
      } 

      return l; 
     } 


     @Override 
     public void write(OutputNode node, List value) throws Exception 
     { 
      // Not required for reading ... 
      throw new UnsupportedOperationException("Not supported yet."); 
     } 
    } 
} 

如何使用：

Serializer ser = new Persister(new AnnotationStrategy()); // Set AnnotationStrategy here! 
List l = ser.read(List.class, yourSourceHere); 

文檔：

• Converter
• AnnotationStrategy

Answer 2

爲了避免解析錯誤不應該把註釋標籤@setË@get

@Root(name = "entries", strict = false) 
public class List { 

@set:ElementList(required = false, entry = "entry", inline = true, empty = true) 
@get:ElementList(required = false, entry = "entry", inline = true, empty = true) 
    private List<Entry> entries; 

} 

@Root 
public class Entry { 

    @set:Element(name = "entry_id", required = true) 
    @get:Element(name = "entry_id", required = true) 
    private long id; 

    @set:Element(name = "text", required = true) 
    @get:Element(name = "text", required = true) 
    private String Text; 
}