编辑:我本来是从我的问题中遗漏了一个重要的细节-返回将要编组的Java对象的服务方法将返回接口类型(Foo)而不是类实现类型(FooImpl)。

我有一个带有JAX-B批注的简单Java类,用于一些元素和属性:

@XmlRootElement(name = "foo")
public class FooImpl {
    private String id;
    private String name;

    @XmlElement
    public String getName() {
            return name;
    }

    public void setName(final String name) {
            this.name = name;
    }

    @XmlAttribute
    public String getId() {
            return Id;
    }

    public void setId(final String id) {
            this.id = id;
    }
}


编辑:FooImpl类具有名为Foo的接口:

public interface Foo {
    public String getName();
    public void setName(final String name);

    public String getId();
    public void setId(final String id);
}


当我有一个返回Foo的服务方法时,我得到了我期望的结果:

<foo id="abc123">
  <name>bar</name>
</foo>


但是我还有另一个包含List<Foo>的类,当将其编组时,foo的XML元素不包含其id属性!

<foos>
    <foo>
      <name>bar1</name>
    </foo>
    <foo>
      <name>bar2</name>
    </foo>
</foos>


包含列表的类如下所示:

@XmlRootElement(name = "foos")
public class Foos {

    private List<Foo> foos;

    @XmlElement(name = "foo")
    public List<Foo> getFoos() {
        return foos;
    }

    public void setFoos(List<Foo> foos) {
        this.foos = foos;
    }

}


我碰巧将MOXy用作我的JAX-B实现,但我认为这并不重要。

最佳答案

注意:我是EclipseLink JAXB (MOXy)负责人,也是JAXB (JSR-222)专家组的成员。

由于您拥有一个类型为接口的属性,因此需要在@XmlElement注释上指定实现类型:

@XmlElement(name = "foo", type=FooImpl.class)
public List<Foo> getFoos() {
   return foos;
}


下面是一个完整的示例:

os

package forum9137171;

import java.util.List;
import javax.xml.bind.annotation.*;

@XmlRootElement(name = "foos")
public class Foos {

    private List<Foo> foos;

    @XmlElement(name = "foo", type=FooImpl.class)
    public List<Foo> getFoos() {
        return foos;
    }

    public void setFoos(List<Foo> foos) {
        this.foos = foos;
    }

}


oo

package forum9137171;

public interface Foo {
    public String getName();
    public void setName(final String name);

    public String getId();
    public void setId(final String id);
}


FoomImpl

package forum9137171;

import javax.xml.bind.annotation.*;

@XmlRootElement(name = "foo")
public class FooImpl implements Foo {
    private String id;
    private String name;

    @XmlElement
    public String getName() {
            return name;
    }

    public void setName(final String name) {
            this.name = name;
    }

    @XmlAttribute
    public String getId() {
            return id;
    }

    public void setId(final String id) {
            this.id = id;
    }
}


演示版

package forum9137171;

import java.io.File;
import javax.xml.bind.*;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(Foos.class);
        System.out.println(jc);

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File xml = new File("src/forum9137171/input.xml");
        Foos foos = (Foos) unmarshaller.unmarshal(xml);

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(foos, System.out);
    }

}


输入输出

org.eclipse.persistence.jaxb.JAXBContext@16a786
<?xml version="1.0" encoding="UTF-8"?>
<foos>
   <foo id="abc123">
      <name>bar1</name>
   </foo>
   <foo id="def456">
      <name>bar2</name>
   </foo>
</foos>


想要查询更多的信息


http://blog.bdoughan.com/2011/05/jaxb-and-interface-fronted-models.html

关于java - JAX-B:子元素上缺少XML属性,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/9137171/

10-12 01:21
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