获取XmlAdapter中的当前主机

Question

有没有办法在XmlAdapter中检索当前的基URI？或者这通常是如何归档的？

public class Service{
...
    @GET
    public MyEntity getEntity() {
        return em.find(MyEntity.class, "dummy");
    }
...
}


@XmlRootElement(name = "myEntity")
public class MyEntity {

    @XmlJavaTypeAdapter(MyAdapter.class)
    private Entity2 entity2Ref;
...

}



public class MyAdapter extends XmlAdapter<Entity2Ref, Entity2> {

// Is NULL but shold be injected with host URI
@Context
UriInfo uri;

...

}

Answer 1

下面是一个完整的示例，说明如何做到这一点：

XML响应

下面我将演示如何获得以下响应，其中address元素中的URI是通过感知UriInfo的XmlAdapter放入的。

<?xml version="1.0" encoding="UTF-8"?>
<customer id="1">
    <name>Jane Doe</name>
    <address>http://localhost:9999/address/123</address>
</customer>

Java模型

下面是我将在本例中使用的Java模型。

客户

默认情况下，Address类的内容将编组到customer元素下。我们将使用XmlAdapter对此进行特殊处理。

import javax.xml.bind.annotation.*;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;

@XmlRootElement
@XmlType(propOrder={"name", "address"})
public class Customer {

    private int id;
    private String name;
    private Address address;

    @XmlAttribute
    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;
    }

    @XmlJavaTypeAdapter(AddressAdapter.class)
    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

}

地址

import javax.xml.bind.annotation.XmlAttribute;

public class Address {

    private int id;

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

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

}

XmlAdapter

下面是我们将使用的XmlAdapter。注意它是如何从AddressResource获取用于构建URI的信息的。它需要一个UriInfo，这使得它是有状态的。我们需要在Marshaller上设置此XmlAdapter的一个实例，以使一切正常工作。

import javax.ws.rs.core.*;
import javax.xml.bind.annotation.adapters.XmlAdapter;

public class AddressAdapter extends XmlAdapter<String, Address> {

    private UriInfo uriInfo;

    public AddressAdapter() {
    }

    public AddressAdapter(UriInfo uriInfo) {
        this.uriInfo = uriInfo;
    }

    @Override
    public Address unmarshal(String v) throws Exception {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public String marshal(Address v) throws Exception {
        if(null == uriInfo) {
            return "";
        }
        UriBuilder builder = UriBuilder.fromResource(AddressResource.class);
        System.out.println(uriInfo.getAbsolutePath().getHost());
        builder.scheme(uriInfo.getAbsolutePath().getScheme());
        builder.host(uriInfo.getAbsolutePath().getHost());
        builder.port(uriInfo.getAbsolutePath().getPort());
        builder.path(AddressResource.class, "get");
        return builder.build(v.getId()).toString();
    }

}

JAX-RS服务

在本例中，有两个服务，一个用于Address，另一个用于Customer。

AddressResource

import javax.ws.rs.*;
import javax.ws.rs.ext.Provider;

@Provider
@Path("/address")
public class AddressResource {

    @GET
    @Path("{id}")
    public Address get(@PathParam("id") int id) {
        Address address = new Address();
        address.setId(id);
        return address;
    }

}

CustomerResource

因为我们有一个有状态的XmlAdapter，所以我们不能仅仅通过缺省绑定来利用JAXB。相反，我们可以通过StreamingOutput访问JAXB。

import javax.ws.rs.*;
import javax.ws.rs.core.*;
import javax.ws.rs.ext.Provider;
import javax.xml.bind.*;

@Provider
@Path("/customer")
public class CustomerResource {

    private JAXBContext jaxbContext;

    public CustomerResource() {
        try {
            jaxbContext = JAXBContext.newInstance(Customer.class);
        } catch (JAXBException e) {
            // TODO - Handle Exception
        }
    }

    @GET
    @Path("{id}")
    @Produces(MediaType.APPLICATION_XML)
    public StreamingOutput get(@Context UriInfo uriInfo, @PathParam("id") int id) {
        Customer customer = new Customer();
        customer.setId(id);
        customer.setName("Jane Doe");

        Address address = new Address();
        address.setId(123);
        customer.setAddress(address);

        return new MyStreamingOutput(jaxbContext, customer, uriInfo);
    }

}

StreamingOutput

import java.io.*;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.*;
import javax.xml.bind.*;

public class MyStreamingOutput implements StreamingOutput {

    private JAXBContext jaxbContext;
    private Object object;
    private UriInfo uriInfo;

    public MyStreamingOutput(JAXBContext jc, Object object, UriInfo uriInfo) {
        this.jaxbContext = jc;
        this.object = object;
        this.uriInfo = uriInfo;
    }

    @Override
    public void write(OutputStream os) throws IOException,
            WebApplicationException {
        try {
            Marshaller marshaller = jaxbContext.createMarshaller();
            marshaller.setAdapter(new AddressAdapter(uriInfo));
            marshaller.marshal(object, os);
        } catch(JAXBException jaxbException) {
            throw new WebApplicationException(jaxbException);
        }
    }

}