Java JAXB 无法处理接口
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/4101718/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
JAXB Can't handle interfaces
提问by user497760
I think this question has been asked like a million times, but none of solutions suggested worked for me. Here is my sample implementation
我认为这个问题已经被问了一百万次，但没有一个建议的解决方案对我有用。这是我的示例实现
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;
}
I always get following exception
我总是得到以下异常
com.sun.xml.bind.v2.runtime.IllegalAnnotationsException: 2 counts of IllegalAnnotationExceptions com.abc.objectsToReturn.Foo is an interface,
com.sun.xml.bind.v2.runtime.IllegalAnnotationsException: 2 个计数的 IllegalAnnotationExceptions com.abc.objectsToReturn.Foo 是一个接口，
can any one help me to figure out right solution
谁能帮我找出正确的解决方案
回答by bdoughan
This isn't really an interface issue, you just need to change the way you bootstrap your JAXBContext.
这并不是真正的接口问题，您只需要更改引导 JAXBContext 的方式。
If you change it to the following:
如果将其更改为以下内容：
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);
}
}
Then you will get the following output (with any JAXB implementation: Metro, MOXy, etc):
然后您将获得以下输出（使用任何 JAXB 实现： Metro、MOXy等）：
<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 allows your entire model to be interfaces, checkout:
MOXy JAXB 允许您的整个模型成为接口，请查看：
I also have a blog post that may be relevant to what you are trying to build:
我还有一篇博客文章，可能与您尝试构建的内容相关：
回答by Aldrin Rodrigues
When you use interfaces just to hide your implementation classes from exposure, and when there's 1-to-1 (or close to 1-on-1) relationship between a class and an interface, XmlJavaTypeAdapter can be used like below.
当您使用接口只是为了隐藏您的实现类而不暴露时，并且当类和接口之间存在一对一（或接近 1 对 1）关系时，可以像下面这样使用 XmlJavaTypeAdapter。
@XmlJavaTypeAdapter(FooImpl.Adapter.class)
interface IFoo {
...
}
class FooImpl implements IFoo {
@XmlAttribute
private String name;
@XmlElement
private int x;
...
static class Adapter extends XmlAdapter<FooImpl,IFoo> {
IFoo unmarshal(FooImpl v) { return v; }
FooImpl marshal(IFoo v) { return (FooImpl)v; }
}
}
class Somewhere {
public IFoo lhs;
public IFoo rhs;
}
