我正在尝试将第三方XML有效负载解组到一个类中。问题是有效负载具有父/子关系,根节点,父节点和子节点都具有相同的元素名称。以下是有效载荷的示例。
<?xml version="1.0" encoding="UTF-8"?>
<Directory>
<id>2</id>
<name>Media</name>
<Directory>
<id>5</id>
<name>Default_Content</name>
<Directory>
<id>9</id>
<name>Images</name>
</Directory>
<Directory>
<id>8</id>
<name>Icons</name>
</Directory>
<Directory>
<id>6</id>
<name>Additional_Content</name>
</Directory>
</Directory>
<Directory>
<id>12</id>
<name>IC</name>
</Directory>
</Directory>
所以我试图注释一个类,所以JAXB / JAX-RS可以将它解组为有用的东西。
我尝试过这样的事情
@XmlRootElement(name="Directory")
public class Directory {
private int id;
private String name;
@XmlElement(name="Directory");
private List<Directory> directories = new ArrayList<Directory>();
}
但是,可以预见,它会抛出一个IllegalAnnotationException
,因为它有两个同名的属性。
关于如何使用JAXB / JAX-RS来干净地处理这个烂摊子的任何想法,还是我应该自己解析它?
答案 0 :(得分:13)
简答
异常是由于字段/属性冲突造成的。您可以注释属性(获取方法)或在类型上设置以下注释:
@XmlAccessorType(XmlAccessType.FIELD)
public class Directory {
...
}
长答案
JAXB的默认访问类型是PUBLIC_MEMBER
,这意味着JAXB将映射所有公共字段(实例变量)和属性(get / set方法)。
public class Foo {
private String bar;
public String getBar() {
return bar;
}
public void setBar(String bar) {
this.bar = bar;
}
}
如果您注释一个字段:
public class Foo {
@XmlAttribute
private String bar;
public String getBar() {
return bar;
}
public void setBar(String bar) {
this.bar = bar;
}
}
然后JAXB会认为它有两个bar
属性映射并抛出异常:
Exception in thread "main" com.sun.xml.bind.v2.runtime.IllegalAnnotationsException: 1 counts of IllegalAnnotationExceptions
Class has two properties of the same name "bar"
this problem is related to the following location:
at public java.lang.String example.Foo.getBar()
at example.Foo
this problem is related to the following location:
at private java.lang.String example.Foo.bar
at example.Foo
解决方案是注释属性并将XmlAccessType类型设置为FIELD
@XmlAccessorType(XmlAccessType.FIELD)
public class Foo {
@XmlAttribute
private String bar;
public String getBar() {
return bar;
}
public void setBar(String bar) {
this.bar = bar;
}
}
您的模型
的目录强> 的
import java.util.ArrayList;
import java.util.List;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
@XmlRootElement(name="Directory")
@XmlAccessorType(XmlAccessType.FIELD)
public class Directory {
private int id;
private String name;
@XmlElement(name="Directory")
private List<Directory> directories = new ArrayList<Directory>();
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<Directory> getDirectories() {
return directories;
}
public void setDirectories(List<Directory> directories) {
this.directories = directories;
}
}
的演示强> 的
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(Directory.class);
Unmarshaller unmarshaller = jc.createUnmarshaller();
Directory directory = (Directory) unmarshaller.unmarshal(new File("input.xml"));
Marshaller marshaller = jc.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.marshal(directory, System.out);
}
}