ContextResolver

ContextResolver

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使用JAXB灵活编组

本文介绍了使用JAXB灵活编组的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我希望有一种灵活的编组方式。单个对象的详细版本和多个对象版本的详细版本。



例如，考虑我的部门模型：



获取/位置/ 1：

 < location id ='1'> 
< link rel =selfhref =http://example.com/locations/1/> 
< link rel =parenthref =http://example.com/serviceareas/1/> 
< name> location 01< / name> 
< departments> 
< department id ='1'> 
< link rel =selfhref =http://example.com/departments/1/> 
< name> department 01< / name> 
< / department> 
< department id ='2'> 
< link rel =selfhref =http://example.com/departments/2/> 
< name> department 02< / name> 
< / department> 
< department id ='3'> 
< link rel =selfhref =http://example.com/departments/3/> 
< name> department 03< / name> 
< / department> 
< / departments> 
< / location>

GET / department / 1：

 < department id ='1'> 
< link rel =selfhref =http://example.com/departments/1/> 
< link rel =parenthref =http://example.com/locations/1/> 
< name> department 01< / name> 
< abbr> dept 01< / abbr> 
 .... 
< special>重症监护< / special> 
< / department>

有没有办法做到这一点？我需要有单独的实体对象吗？一个引用CRUD操作表而另一个引用列表？

解决方案

注意：我是领导，以及专家如果您使用的是 EclipseLink JAXB（MOXy） strong>您可以利用外部绑定文档将第二个映射应用于 Department 类。





ContextResolver



在 JAX-RS 环境中，您可以通过 ContextResolver 来利用MOXy的外部绑定文档：

  import java.io. *; 
 import java.util。*; 
 import javax.ws.rs.Produces; 
 import javax.ws.rs.ext。*; 
 import javax.xml.bind。*; 
 import org.eclipse.persistence.jaxb.JAXBContextFactory; 
 
 @Provider 
 @Produces（{application / xml，application / json}）
公共类DepartmentContextResolver实现ContextResolver< JAXBContext> {
 
 private JAXBContext jc; 
 
 public DepartmentContextResolver（）{
 try {
 Map< String，Object> props = new HashMap< String，Object>（1）; 
 props.put（JAXBContextFactory.ECLIPSELINK_OXM_XML_KEY，example / bindings.xml）; 
 jc = JAXBContext.newInstance（new Class [] {Department.class}，props）; 
} catch（JAXBException e）{
抛出新的RuntimeException（e）; 
} 
} 
 
 public JAXBContext getContext（Class<？> clazz）{
 if（Department.class == clazz）{
 return jc ; 
} 
返回null; 
} 
 
 
}

更多信息










外部装订文件



默认情况下，MOXy的外部绑定文档用于扩充带注释的模型，但如果设置 xml-mapping-metadata-complete 标志，它将完全覆盖允许您的注释应用完全不同的映射：

 < xml-bindings 
 xmlns =http：//www.eclipse .ORG /的EclipseLink / XSD文件/持续ence / oxm
 package-name =example
 xml-mapping-metadata-complete =true> 
 ... 
< / xml-bindings>

更多信息








更新



此更新旨在解答您在一条评论中提出的一些问题：

是每个 ContextResolver 应该有自己的绑定文件。引入新的 ContextResolver 的主要原因是表示辅助映射。

对于单个 ContextResolver ，您可以在多个绑定文件中表达元数据，但它们将合并为一组映射。这意味着单个 ContentResolver 不能拥有单个类的多个视图。单独的 ContextResolver 用于表示辅助映射。

我建议从类路径加载元数据文件。







你的JAX-RS实现应该拿起 ContextResolver 因为它是用 @Provider 注释的。用于类的 ContextResolver 将取决于您如何实现 getContext 方法：

  public JAXBContext getContext（Class<？> clazz）{
 if（Customer.class == clazz）{
 return jc; 
} 
返回null; 
}


I'm hoping to have a flexible way of marshalling objects. A verbose version for single objects and a less-verbose version for multiple object versions.

For example, consider my department model:

GET /locations/1:

  <location id='1'>
    <link rel="self" href="http://example.com/locations/1"/>
    <link rel="parent" href="http://example.com/serviceareas/1"/>
    <name>location 01</name>
    <departments>
      <department id='1'>
        <link rel="self" href="http://example.com/departments/1"/>
        <name>department 01</name>
      </department>
      <department id='2'>
        <link rel="self" href="http://example.com/departments/2"/>
        <name>department 02</name>
      </department>
      <department id='3'>
        <link rel="self" href="http://example.com/departments/3"/>
        <name>department 03</name>
      </department>
    </departments>
  </location>

GET /department/1:

<department id='1'>
  <link rel="self" href="http://example.com/departments/1"/>
  <link rel="parent" href="http://example.com/locations/1"/>
  <name>department 01</name>
  <abbr>dept 01</abbr>
  ....
  <specialty>critical care</specialty>
</department>

Is there a way to do this? Would I need to have separate entity objects? One that references the table for CRUD operations and another for lists?

解决方案

Note: I'm the EclipseLink JAXB (MOXy) lead, and a member of the JAXB 2 (JSR-222) expert group.

Your question is tagged EclipseLink, if you are using EclipseLink JAXB (MOXy) you can take advantage of the external binding document to apply a second mapping to the Department class.

ContextResolver

In a JAX-RS environment you can leverage MOXy's external binding document through a ContextResolver:

import java.io.*;
import java.util.*;
import javax.ws.rs.Produces;
import javax.ws.rs.ext.*;
import javax.xml.bind.*;
import org.eclipse.persistence.jaxb.JAXBContextFactory;

@Provider
@Produces({"application/xml", "application/json"})
public class DepartmentContextResolver implements ContextResolver<JAXBContext> {

    private JAXBContext jc;

    public DepartmentContextResolver() {
        try {
            Map<String, Object> props = new HashMap<String, Object>(1);
            props.put(JAXBContextFactory.ECLIPSELINK_OXM_XML_KEY, "example/bindings.xml");
            jc = JAXBContext.newInstance(new Class[] {Department.class} , props);
        } catch(JAXBException e) {
            throw new RuntimeException(e);
        }
    }

    public JAXBContext getContext(Class<?> clazz) {
        if(Department.class == clazz) {
            return jc;
        }
        return null;
    }


}

For More Information

External Binding Document

By default MOXy's external binding document is used to augment the annotated model, but if you set the xml-mapping-metadata-complete flag it will completely override the annotations allowing you to apply a completely different mapping:

<xml-bindings
    xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm"
    package-name="example"
    xml-mapping-metadata-complete="true">
    ...
</xml-bindings>

For More Information

UPDATE

This update is to address a number of questions you asked in one of your comments:

Yes each ContextResolver should have its own binding file. The main reason for introducing a new ContextResolver is to represent a secondary mapping.

For a single ContextResolver you can express the metadata across multiple binding files, but they will be combined into a single set of mappings. This means that a single ContentResolver cannot have multiple views of a single class. A separate ContextResolver is used to represent a secondary mapping.

I recommend loading the metadata file from the class path.

Your JAX-RS implementation should pick up your ContextResolver because it is annotated with @Provider. The ContextResolver used for a class will depend on how you implement the getContext method:

public JAXBContext getContext(Class<?> clazz) {
    if(Customer.class == clazz) {
        return jc;
    }
    return null;
}

这篇关于使用JAXB灵活编组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！

06-10 05:43
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