目前我的程序有以下输出:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<container>
<elements>
<property name="e1">
<foo name="Alex" status="Married"/>
</property>
<property name="e2">
<foo name="Chris" status="Married with 2 children"/>
</property>
</elements>
</container>
如您所见,同时拥有 <container>
和<elements>
标签是没有用的。我想删除<elements>
,因此输出如下所示:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<container>
<property name="e1">
<foo name="Alex" status="Married"/>
</property>
<property name="e2">
<foo name="Chris" status="Married with 2 children"/>
</property>
</container>
下面列出了生成第一个输出的代码:
@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Container {
@XmlElement
@XmlJavaTypeAdapter(MyAdapter.class)
private Map<String, Foo> elements = new HashMap<String, Foo>();
public Container() {
this.elements = new HashMap<String, Foo>();
}
public Map<String, Foo> getElements() {
return elements;
}
@XmlAccessorOrder(XmlAccessOrder.ALPHABETICAL)
@XmlRootElement(name = "foo")
static class Foo {
@XmlAttribute
public String name;
@XmlAttribute
public String status;
public Foo(String name, String status) {
this.name = name;
this.status = status;
}
public Foo() {
}
}
public static void main(String[] args) throws JAXBException {
final JAXBContext context = JAXBContext.newInstance(Container.class);
final Marshaller m = context.createMarshaller();
m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
final Container c = new Container();
final Map<String, Foo> elementsMap = c.getElements();
elementsMap.put("e1", new Foo("Alex", "Married"));
elementsMap.put("e2", new Foo("Chris", "Married with 2 children"));
m.marshal(c, System.out);
}
}
和MyAdapter
类,基于JAXB @XmlAdapter: Map -> List adapter? (marshall only) :
public class MyAdapter extends XmlAdapter<MyAdapter.AdaptedFoo, Map<String, Foo>> {
static class AdaptedFoo {
public List<Property> property = new ArrayList<>();
}
public static class Property {
@XmlAttribute
public String name;
@XmlElementRef(type = Foo.class)
public Foo value;
}
@Override
public Map<String, Foo> unmarshal(AdaptedFoo v) throws Exception {
return null;
}
@Override
public AdaptedFoo marshal(Map<String, Foo> map) throws Exception {
if (null == map) {
return null;
}
AdaptedFoo adaptedFoo = new AdaptedFoo();
for (Entry<String, Foo> entry : map.entrySet()) {
Property property = new Property();
property.name = entry.getKey();
property.value = entry.getValue();
adaptedFoo.property.add(property);
}
return adaptedFoo;
}
}
如何删除 <elements>
我的输出中的标签?
编辑:我找到了“肮脏”的方法 - 设置 @XmlRootElement(name = "")
对于 Container
类。但有什么“优雅”的方式吗?
最佳答案
XML 元素 <elements>
需要将封闭的元素序列与属性 Map<?,?> elements
相关联。你不能丢弃它:解码器如何知道 <property>
在哪里?元素属于*元素 <container>
的级别.
拥有 List<Property>
是不同的,因为 JAXB 将重复元素 x“硬连线”处理为 List<?> x
,所以不需要包装器。
由于您使用注释编写 Java 类,因此您可以通过添加(到容器)另一个“虚拟”字段并修改一些注释来使用它:
@XmlAccessorType(XmlAccessType.PROPERTY)
public class Container {
// ...
@XmlTransient
public Map<String,Foo> getElements(){
return elements;
}
private List<Property> property;
@XMLElement
public List<Property> getProperty(){
List<Property> props = elements.entrySet().stream()
.map( e -> new Property( e.getKey(), e.getValue() )
.collect( Collectors.toList() );
return props;
}
较旧的 Java 可能会这样做
List<Property> props = new ArrayList<>();
for( Map.Entry<String,Foo> e: elements.entrySet() ){
props.add( new Property( e.getKey(), e.getValue() ) );
}
return props;
这个编码是这样的:
<container>
<property name="aaa">
<foo name="aaaname" status="aaastatus"/>
</property>
<property name="bbb">
<foo name="bbbname" status="bbbstatus"/>
</property>
</container>
它不会解码!
关于java - JAXB 删除不必要的嵌套 XML 标记,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/25246493/