java 如何在 JAXB 中使用 hashmap 属性？
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How to use hashmap properties with JAXB?
提问by opensourcegeek
I've been fiddling around with JAXB for a while now, I need to generate xml like below
我一直在摆弄 JAXB 一段时间，我需要生成如下的 xml
<Root attr1="" attr2="" .. attrn="" >
<CNode attr1="" attr2="" />
.
.
.
<CNode .. />
</Root>
The attributes of Root element is dynamic and would come from either a properties file or a template. What is the best way to get it into the structure as shown above? I'm using hashmaps for dynamic variables and then tried mapping it with XmlJavaTypeAdapter, the best I could do is
Root 元素的属性是动态的，可以来自属性文件或模板。将其放入如上所示结构的最佳方法是什么？我对动态变量使用哈希图，然后尝试用 XmlJavaTypeAdapter 映射它，我能做的最好的是
<Root>
<Attribs>
<entry key="attr1">Value</entry>
</Attribs>
<CNode .. />
</Root>
Is there a way in jaxb to say use hashmap's key as the attribute name and the value for that key as the value for that attribute in xml? Or if you think there is a better way to do it, I'm open for suggestions. I'm quite thinking about using jaxb's marshaller to add the Root node separately. However it would be nicer if I can just use jaxb's adapter. Thanks!
在 jaxb 中有没有办法说使用 hashmap 的键作为属性名称，将该键的值作为 xml 中该属性的值？或者，如果您认为有更好的方法可以做到，我愿意提供建议。很想用jaxb的marshaller来分别添加Root节点。但是，如果我可以使用 jaxb 的适配器会更好。谢谢！
回答by bdoughan
@XmlAnyAttribute is along the lines of what you need:
@XmlAnyAttribute 符合您的需求：
Root
根
import java.util.List;
import java.util.Map;
import javax.xml.bind.annotation.XmlAnyAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.namespace.QName;
@XmlRootElement(name="Root")
public class Root {
private Map<QName, String> extension;
private List<CNode> cnodes;
@XmlAnyAttribute
public Map<QName, String> getExtension() {
return extension;
}
public void setExtension(Map<QName, String> extension) {
this.extension = extension;
}
@XmlElement(name="CNode")
public List<CNode> getCnodes() {
return cnodes;
}
public void setCnodes(List<CNode> cnodes) {
this.cnodes = cnodes;
}
}
CNode
节点
import java.util.Map;
import javax.xml.bind.annotation.XmlAnyAttribute;
import javax.xml.namespace.QName;
public class CNode {
private Map<QName, String> extension;
@XmlAnyAttribute
public Map<QName, String> getExtension() {
return extension;
}
public void setExtension(Map<QName, String> extension) {
this.extension = extension;
}
}
Demo
演示
import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
public class Demo {
public static void main(String[] args) throws Exception {
JAXBContext jc = JAXBContext.newInstance(Root.class);
Unmarshaller unmarshaller = jc.createUnmarshaller();
Root root = (Root) unmarshaller.unmarshal(new File("input.xml"));
Marshaller marshaller = jc.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.marshal(root, System.out);
}
}
input.xml
输入文件
<?xml version="1.0" encoding="UTF-8"?>
<Root att1="A" att2="B">
<CNode att3="C" att4="D"/>
<CNode att5="E" att6="F"/>
</Root>
