JAXB 无法处理接口 [英] JAXB Can't handle interfaces

问题描述

我认为这个问题已被问了一百万次，但没有一个建议的解决方案对我有用.这是我的示例实现

I think this question has been asked like a million times, but none of solutions suggested worked for me. Here is my sample implementation

public class FooImpl2 implements Foo {
    private int a = 100 ;
    private String b = "I am FooImpl2";
    private boolean c;

    public int getA() {
        return a;
    }
    public void setA(int a) {
        this.a = a;
    }
    public String getB() {
        return b;
    }
    public void setB(String b) {
        this.b = b;
    }
    public boolean isC() {
        return c;
    }
    public void setC(boolean c) {
        this.c = c;
    }

}

@XmlRootElement
@XmlSeeAlso({FooImpl1.class, FooImpl2.class})
public interface Foo {}

public class FooImpl1 implements Foo {    
    private int x;
    private String y ="I am FooImpl1";
    private boolean z;

    public int getX() {
        return x;
    }
    public void setX(int x) {
        this.x = x;
    }
    public String getY() {
        return y;
    }
    public void setY(String y) {
        this.y = y;
    }
    public boolean isZ() {
        return z;
    }
    public void setZ(boolean z) {
        this.z = z;
    }        
}

@XmlRootElement
public class Response{

    private Foo foo;

    @XmlElement(type=Object.class)
    public Foo getFoo() {
        return foo;
    }

    public void setFoo(Foo foo) {
        this.foo = foo;
    }

}

public class SimpleResource {    
    @Path("foo/{val}") @Produces({"application/json"}) @GET
    public FooAdapter getFoo(@QueryParam("val") int val) {
        FooAdapter ret = new FooAdapter();
        if(val % 2 == 0) {
            ret.setFoo(new FooImpl2());
        } else {
            ret.setFoo(new FooImpl1());
        }

        return ret;
    }

我总是遇到以下异常

com.sun.xml.bind.v2.runtime.IllegalAnnotationsException: 2 个计数非法注释异常com.abc.objectsToReturn.Foo 是一个界面，

com.sun.xml.bind.v2.runtime.IllegalAnnotationsException: 2 counts of IllegalAnnotationExceptions com.abc.objectsToReturn.Foo is an interface,

谁能帮我找出正确的解决方案

can any one help me to figure out right solution

推荐答案

这并不是真正的接口问题，您只需要更改引导 JAXBContext 的方式.

This isn't really an interface issue, you just need to change the way you bootstrap your JAXBContext.

如果你改成如下:

import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(Response.class, FooImpl1.class, FooImpl2.class);

        Response response = new Response();
        FooImpl1 foo = new FooImpl1();
        response.setFoo(foo);

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

然后您将获得以下输出(使用任何 JAXB 实现:Metro, MOXy 等):

Then you will get the following output (with any JAXB implementation: Metro, MOXy, etc):

<response>
   <foo xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="fooImpl1">
      <x>0</x>
      <y>I am FooImpl1</y>
      <z>false</z>
   </foo>
</response>

MOXy JAXB 允许您的整个模型成为接口，结帐:

MOXy JAXB allows your entire model to be interfaces, checkout:

• http://bdoughan.blogspot.com/2010/07/moxy-jaxb-map-interfaces-to-xml.html

我还有一篇可能与您尝试构建的内容相关的博文:

I also have a blog post that may be relevant to what you are trying to build:

• http://bdoughan.blogspot.com/2010/08/using-xmlanyelement-to-build-generic.html

这篇关于JAXB 无法处理接口的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！