JAXB Eclipse MOXy可空值，并且仅检索Map中的指定键 [英] JAXB Eclipse MOXy Nullable value and retrieve only a specified key in a Map
问题描述
我还有另一个更棘手的问题：
I have another more tricky question:
E.g. Person Class has: --String firstName --String lastName --Map stringMap
Person person = new Person ();
person.setFirstName("FirstName");
person.setLastName("LastName");
Map<String,String> stringMap = new HashMap<String,String>();
stringMap.put("IwantThisKeyInXml","IwantThisValueInXml");
stringMap.put("IDONTwantThisKeyInXml","IDONTwantThisValueInXml");
InputStream iStream1 = classLoader.getResourceAsStream("person-binding.xml");
List<Object> fileList = new ArrayList<Object>();
fileList.add(iStream1);
Map<String, Object> properties = new HashMap<String,Object>();
properties.put(JAXBContextProperties.OXM_METADATA_SOURCE, fileList);
JAXBContext ctx = JAXBContext.newInstance(new Class[] { GaDictionary.class, Person.class }, properties);
Marshaller marshaller = ctx.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
Writer output = new StringWriter();
marshaller.marshal(person, output);
System.out.println(output);
person-binding.xml低于
person-binding.xml is below
<?xml version="1.0"?>
<xml-bindings
xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm"
package-name="my.test.model" xml-mapping-metadata-complete="true">
<xml-schema
element-form-default="QUALIFIED"/>
<java-types>
<java-type name="Person" xml-accessor-type="NONE">
<xml-root-element/>
<xml-type prop-order="firstName lastName"/>
<java-attributes>
<xml-element java-attribute="firstName" name="first-name"/>
<xml-element java-attribute="lastName" name="last-name"/>
<xml-element java-attribute="stringMap" name="string-map"/>
</java-attributes>
</java-type>
</java-types>
</xml-bindings>
因此，相应的定义结果是：
So accordingly the definition the result is:
<?xml version="1.0" encoding="UTF-8"?>
<person>
<first-name>FirstName</first-name>
<last-name>LastName</last-name>
<string-map>
<entry>
<key>IwantThisKeyInXml</key>
<value>IwantThisKeyInXml</value>
</entry>
<entry>
<key>IDONTwantThisKeyInXml</key>
<value>IDONTwantThisKeyInXml</value>
</entry>
</string-map>
</person>
如何在stringMap上排除该条目？我尝试使用虚拟访问方法，但可能无法正确配置它！封送处理后是否应该删除该值？
How Could I exclude that entry on the stringMap? I tried with virtual access method but maybe I wasn't able to configure it properly?! Should I remove that value after marshaling? Which could it be a smart and maintainable way?
最后一个问题是，如果我的属性值为空。我如何配置person-binding-xml文件（oxm.file）以使相关xml标签为空？
Last question is if I have null value for a property. How could I configure the person-binding-xml file (oxm.file) to get the relative xml tag empty?
我可以更改模型类，但我更喜欢不要如果可能，请添加任何代码行。 （这就是我填充xml文件的原因）
I could change the model class but I prefer don't add any lines of code if it's possible. (This is the reason why I populated the xml file)
所以我想要获得的结果是：
So the result that I would like to obtain is:
<?xml version="1.0" encoding="UTF-8"?>
<person>
<first-name>FirstName</first-name>
<last-name>LastName</last-name>
<string-map>
<entry>
<key>IwantThisKeyInXml</key>
<value>IwantThisKeyInXml</value>
</entry>
</string-map>
</person>
对于第二个相关问题：
我尝试了nillable = true，但它没有不行！
因此，如果我对stringMap或firstName或其他任何东西使用null值，我将分别获得
并用任何主体将标签关闭。
For the second related question: I tried nillable="true" in but it doesn't work ! So For istance If I have a null value for a stringMap or firstName or something else I will get respectively and tag closed with any body.
或者我想获取的另一种方法是：
Or another way that I would like to obtain is:
<?xml version="1.0" encoding="UTF-8"?>
<person>
<first-name>FirstName</first-name>
<last-name>LastName</last-name>
<string-map>
<entry>
<key>IwantThisKeyInXml</key>
<value>IwantThisKeyInXml</value>
</entry>
<entry><!-- I have the entry but I have an empty value-->
<key>KEY</key>
<value></value>
</entry>
</string-map>
</person>
感谢所有人
推荐答案
我找到了正确的解决方案：
I found the right solution:
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import javax.xml.bind.annotation.adapters.XmlAdapter;
public final class StringMapAdapter extends XmlAdapter<StringAdapterMap, Map<String, String>> {
private final String OMIT = "birthPlaceString";
@Override
public Map<String, String> unmarshal(StringAdapterMap v) throws Exception {
HashMap<String, String> hashMap = new HashMap<String, String>();
System.out.println("unmarshal");
for(StringEntryType myEntryType : v.entry) {
hashMap.put(myEntryType.key, myEntryType.value);
}
return hashMap;
}
@Override
public StringAdapterMap marshal(Map<String, String> v) throws Exception {
StringAdapterMap myMapType = new StringAdapterMap();
for(Entry<String, String> entry : v.entrySet()) {
StringEntryType EntryType = new StringEntryType();
EntryType.key= entry.getKey();
EntryType.value = entry.getValue();
if (!OMIT.equals(EntryType.key))
myMapType.entry.add(EntryType);
}
return myMapType;
}
StringAdapterMap类：
StringAdapterMap class:
import java.util.ArrayList;
import java.util.List;
public class StringAdapterMap {
public List<StringEntryType> entry = new ArrayList<StringEntryType>();
}
StringEntryType类：
StringEntryType class:
public class StringEntryType {
public String key;
public String value;
}
记住配置适配器
<xml-element java-attribute="stringMap" name="string-map" >
<xml-java-type-adapter value="it.cineca.jaxb.adapter.StringMapAdapter" />
</xml-element>
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