java.util.Date和XMLGregorianCalendar之间的简单转换 [英] Simple conversion between java.util.Date and XMLGregorianCalendar

问题描述

我正在寻找一种在两个方向上在java.util.Date和javax.xml.datatype.XMLGregorianCalendar之间转换的简单方法。

I'm looking for a simple method of converting between java.util.Date and javax.xml.datatype.XMLGregorianCalendar in both directions.

以下是我现在使用的代码：

import java.util.GregorianCalendar;
import javax.xml.datatype.DatatypeConfigurationException;
import javax.xml.datatype.DatatypeFactory;
import javax.xml.datatype.XMLGregorianCalendar;

/**
 * Utility class for converting between XMLGregorianCalendar and java.util.Date
 */
public class XMLGregorianCalendarConverter {  

    /**
     * Needed to create XMLGregorianCalendar instances
     */
    private static DatatypeFactory df = null;
    static {
        try {
            df = DatatypeFactory.newInstance();
        } catch (DatatypeConfigurationException dce) {
            throw new IllegalStateException(
                "Exception while obtaining DatatypeFactory instance", dce);
        }
    }  

    /**
     * Converts a java.util.Date into an instance of XMLGregorianCalendar
     *
     * @param date Instance of java.util.Date or a null reference
     * @return XMLGregorianCalendar instance whose value is based upon the
     *  value in the date parameter. If the date parameter is null then
     *  this method will simply return null.
     */
    public static XMLGregorianCalendar asXMLGregorianCalendar(java.util.Date date) {
        if (date == null) {
            return null;
        } else {
            GregorianCalendar gc = new GregorianCalendar();
            gc.setTimeInMillis(date.getTime());
            return df.newXMLGregorianCalendar(gc);
        }
    }

    /**
     * Converts an XMLGregorianCalendar to an instance of java.util.Date
     *
     * @param xgc Instance of XMLGregorianCalendar or a null reference
     * @return java.util.Date instance whose value is based upon the
     *  value in the xgc parameter. If the xgc parameter is null then
     *  this method will simply return null.
     */
    public static java.util.Date asDate(XMLGregorianCalendar xgc) {
        if (xgc == null) {
            return null;
        } else {
            return xgc.toGregorianCalendar().getTime();
        }
    }
}

有什么吗更简单，像我忽略的一些API调用？

在标准XML日期/时间与Java日期对象之间进行转换似乎是一个非常常规的任务，我很惊讶，我必须写这个代码。

Converting between a standard XML date/time and a Java date object seems like a pretty routine task and I'm surprised that I have to write this code at all.

任何建议？

注意：
我的JAXB类是从模式自动生成的。我的项目的构建过程不允许我对生成的类进行手动更改。 xs：dateTime元素由XJC在JAXB类中生成为XMLGregorianCalendar。该架构定期扩展和调整，因此我可以对架构XSD文件进行有限的更改。

NOTES: My JAXB classes are autogenerated from a schema. The build process on my project does not allow for me to make manual changes to the generated classes. The xs:dateTime elements are being generated by XJC as XMLGregorianCalendar in the JAXB classes. The schema is extended and tweaked periodically, so I am allowed to make limited changes to the schema XSD file.

更新解决方案：
Blaise提出的解决方案允许我将XMLGregorianCalendar从混合中取代，并处理java.util.Calendar对象。通过在我的模式文件的顶部添加一个JAXB绑定子句，XJC能够在我的JAXB类中为xs：dateTime生成更合适的映射。以下是一些在XSD文件中显示修改的片段。

UPDATE ON SOLUTION: The solution proposed by Blaise has allowed me to take XMLGregorianCalendar out of the mix and deal with java.util.Calendar objects instead. By adding a JAXB binding clause at the top of my schema file, XJC is able to generate more appropriate mappings for xs:dateTime in my JAXB classes. Here are some snippets that show the modifications in my XSD file.

XSD文件中的根元素：

<xs:schema xmlns:mydata="http://my.example.com/mydata" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:jaxb="http://java.sun.com/xml/ns/jaxb" targetNamespace="http://my.example.com/mydata" elementFormDefault="unqualified" attributeFormDefault="unqualified" version="0.2" xml:lang="en" jaxb:version="2.0">

JAXB绑定注释块，立即插入XSD中的根元素后：

<xs:annotation>
    <xs:appinfo>
        <jaxb:globalBindings>
            <jaxb:javaType name="java.util.Calendar" xmlType="xs:dateTime" parseMethod="javax.xml.bind.DatatypeConverter.parseDateTime" printMethod="javax.xml.bind.DatatypeConverter.printDateTime" />
        </jaxb:globalBindings>
    </xs:appinfo>
</xs:annotation>

由于XML xs：dateTime字段也存储时区，因此我可以使用日历而不是日期，因为Calendar对象有一个非常好的API使用区域设置和时区。无论如何，我更乐意处理Calendar对象而不是XMLGregorianCalendar。不需要我上面列出的转换方法。我没有得到所有的方式到java.util.Date，但足够接近！

Since the XML xs:dateTime field also stores timezone, it might be better for me to work with Calendar instead of Date anyway since Calendar objects have a pretty good API for working with locales and timezones. In any case, I'm much happier to deal with Calendar objects instead of XMLGregorianCalendar. No need for the conversion methods that I listed above anymore. I didn't get all the way to java.util.Date, but close enough!

推荐答案

为什么不使用外部绑定文件告诉XJC生成java.util.Date字段而不是XMLGregorianCalendar？

Why not use an external binding file to tell XJC to generate java.util.Date fields instead of XMLGregorianCalendar?

另请参阅：
- http://weblogs.java.net/blog/kohsuke/archive/2006/03/how_do_i_map_xs.html

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