JAXB XmlJavaTypeAdapter解组方法不被调用

Question

我正在尝试编组/解组一个Color到XML。 JAXB项目有通过XmlJavaTypeAdapter https://jaxb.java.net/guide/XML_layout_and_in_memory_data_layout.html完成这件事的示例代码。

的整编工作正常，并输出为我所期望的：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?> 
<beanWithColor> 
    <foreground>#ff0000ff</foreground> 
    <name>CleverName</name> 
</beanWithColor> 

然而，试图从XML去反对解组方法时不会被调用。任何人都可以提供洞察力为什么？之后，它是解组前景色为空，我已经与我的调试器，解组是从来没有被称为证实：

BeanWithColor{foreground=null, name='CleverName'} 

SCCE：

@XmlRootElement 
public class BeanWithColor { 
private String name; 
private Color foreground; 

public BeanWithColor() { 

} 

public BeanWithColor(Color foreground, String name) { 
    this.foreground = foreground; 
    this.name = name; 
} 

@XmlJavaTypeAdapter(ColorAdapter.class) 
public Color getForeground() { 
    return this.foreground; 
} 

public void setForeground(Color foreground) { 
    this.foreground = foreground; 
} 

public String getName() { 
    return name; 
} 

public void setName(String name) { 
    this.name = name; 
} 

@Override 
public String toString() { 
    final StringBuilder sb = new StringBuilder("BeanWithColor{"); 
    sb.append("foreground=").append(foreground); 
    sb.append(", name='").append(name).append('\''); 
    sb.append('}'); 
    return sb.toString(); 
} 

public static void main(String[] args) { 
    BeanWithColor bean = new BeanWithColor(Color.blue, "CleverName"); 

    try { 
     StringWriter writer = new StringWriter(1000); 
     JAXBContext context = JAXBContext.newInstance(BeanWithColor.class); 
     final Marshaller marshaller = context.createMarshaller(); 
     marshaller.marshal(bean, writer); 
     System.out.println("Marshaled XML: " + writer); 

     final Unmarshaller unmarshaller = context.createUnmarshaller(); 
     BeanWithColor beanWithColor = (BeanWithColor) unmarshaller.unmarshal(new StringReader(writer.toString())); 
     System.out.println("beanWithColor = " + beanWithColor); 
    } catch (JAXBException e) { 
     e.printStackTrace(); 
    } 

} 

static class ColorAdapter extends XmlAdapter<String, Color> { 
    public Color unmarshal(String s) { 
     return Color.decode(s); 
    } 

    public String marshal(Color color) { 
     return '#' + Integer.toHexString(color.getRGB()); 
    } 
} 
} 

Answer 1

我怀疑XmlAdapter正在呼吁unmarshal但该Color.decode方法失败（这是我调试代码时发生的情况）。

Color.decode("#ff0000ff"); 

结果如下：

Exception in thread "main" java.lang.NumberFormatException: For input string: "ff0000ff" 
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48) 
    at java.lang.Integer.parseInt(Integer.java:461) 
    at java.lang.Integer.valueOf(Integer.java:528) 
    at java.lang.Integer.decode(Integer.java:958) 
    at java.awt.Color.decode(Color.java:707) 

您可以设置在Unmarshaller一个ValidationEventHandler让所有失败的钩子。默认情况下，JAXB impl不会报告该问题。

的修复

ColorAdapter.marshal该方法需要固定到返回正确的值。

String rgb = Integer.toHexString(color.getRGB()); 
return "#" + rgb.substring(2, rgb.length());