[jakarta-commons] 使用Digester解释xml获取java对象(代码入注规则或配置规则任你选！)

今天看了八进制的《利用Digester把XML转换为Java对象》，感觉挺好。你可以在这里http://www.cnblogs.com/bjzhanghao/archive/2007/05/15/125747.html访问。加上混北民工的在评论中更详细一点的例子。终于对Digester有了初步的了解。但是，对于详细返回对象，在八进制和混北民工的例子中表现得不是十分明朗。下面，我对例子做了一些修改，使Digester的规则表现清晰一些，另外添加配置规则来代替代码入注规则的运用方法。

注册表ChartRegistry：

public class ChartRegistry

{

List<ChartConfig> registry = new ArrayList<ChartConfig>();

public void addChart(ChartConfig obj)

{

registry.add(obj);

}

public java.util.List<ChartConfig> getRegistry()

{

return registry;

}

public String toString() {

return ReflectionToStringBuilder.reflectionToString(this, ToStringStyle.MULTI_LINE_STYLE);

}

图表设定器ChartConfig：

public class ChartConfig implements Comparable

{

private String id;

private boolean legendVisible;

private String type;

private int width;

private String description;

public String getDescription()

{

return description;

}

public void setDescription(String description)

{

this.description = description;

}

public String getId()

{

return id;

}

public void setId(String id)

{

this.id = id;

}

public boolean isLegendVisible()

{

return legendVisible;

}

public void setLegendVisible(boolean legendVisible)

{

this.legendVisible = legendVisible;

}

public String getType()

{

return type;

}

public void setType(String type)

{

this.type = type;

}

public int getWidth()

{

return width;

}

public void setWidth(int width)

{

this.width = width;

}

public String toString() {

return ReflectionToStringBuilder.reflectionToString(this,ToStringStyle.MULTI_LINE_STYLE);

}

public int compareTo(Object o)

{

if(o instanceof ChartConfig){

ChartConfig o1 = (ChartConfig)o;

return this.id.compareTo(o1.id);

}

return -1;

}

图表数据设定（简化版）charts.xml：

<?xml version="1.0" encoding="GBK" ?>

<legendVisible>false</legendVisible>

</chart>

</chart>

</charts>

配置规则设定rule.xml：

<?xml version='1.0'?>

<!DOCTYPE digester-rules

PUBLIC "-//Jakarta Apache //DTD digester-rules XML V1.0//EN"

"file:///../digester/dtds/digester-rules.dtd">

<digester-rules>

<set-properties-rule />

<set-next-rule methodname="addChart" paramtype="study.jakarta.commons.digester.ChartConfig"/>

<set-properties-rule />

<bean-property-setter-rule pattern="legendVisible" />

<bean-property-setter-rule pattern="type" />

<bean-property-setter-rule pattern="width" />

<bean-property-setter-rule pattern="description" />

</pattern>

</digester-rules>

跑一下试试看：

public class DigesterTest

{

public static void main(String[] args)

{

try

{

String charts = "F:\\计算机\\jakarta-commons\\jakarta-commons-cookbook-code\\examples\\study\\jakarta\\commons\\digester\\charts.xml";

String rule="F:\\计算机\\jakarta-commons\\jakarta-commons-cookbook-code\\examples\\study\\jakarta\\commons\\digester\\rules.xml";

DigesterTest test= new DigesterTest();

System.out.println("======================= getChartRegistryWithCodeRule ==========================");

ChartRegistry c= test.getChartRegistryWithCodeRule(new File(charts));

System.out.println(c);

System.out.println("======================= getChartRegistryWithCodeRule ==========================");

System.out.println(test.getChartRegistryWithFileRule(new File(charts),new File(rule)));

}

catch(Exception e)

{

e.printStackTrace();

}

//代码中设定规则

private ChartRegistry getChartRegistryWithCodeRule(File charts) throws IOException, SAXException{

InputStream is = new FileInputStream(charts);

Digester digester = new Digester();

digester.setValidating(false);//不进行XML与相应的DTD的合法性验证

digester.push(new ChartRegistry()); //创建一个ChartRegistry对象, 你这样用这种形式建立顶对象（选用这种方式，注释下一行）

//digester.addObjectCreate("charts", ChartRegistry.class); //创建一个ChartRegistry对象, 你也这样用这种形式建立顶对象（选用这种方式，注释上一行）

digester.addSetProperties("charts");

digester.addObjectCreate("charts/chart", ChartConfig.class); //当遇到<chart>时创建一个ChartConfig对象

digester.addSetProperties("charts/chart"); //根据<chart>元素的属性(attribute)，对刚创建的ChartConfig对象的属性(property)进行设置

digester.addBeanPropertySetter("charts/chart/legendVisible");//当遇到<chart>的子元素<legendVisible>时将子元素值设置为ChartConfig对象的legendVisible属性的setter方法

digester.addBeanPropertySetter("charts/chart/type"); //参考上面注释

digester.addBeanPropertySetter("charts/chart/width"); //参考上面注释

digester.addBeanPropertySetter("charts/chart/description"); //参考上面注释

digester.addSetNext("charts/chart", "addChart"); //当再次遇到<charts>的子元素<chart>时调用顶对象的addChart方法。

ChartRegistry c = (ChartRegistry)digester.parse(is); //分析结束后，返回根元素

Collections.sort(c.getRegistry());

return c;

}

//配置中设定规则

private ChartRegistry getChartRegistryWithFileRule(File charts,File rule) throws IOException, SAXException{

Digester digester = DigesterLoader.createDigester(rule.toURL());

ChartRegistry c = (ChartRegistry)digester.parse(charts);

Collections.sort(c.getRegistry());

return c;

}

结果输出：

======================= getChartRegistryWithCodeRule ==========================

study.jakarta.commons.digester.ChartRegistry@16df84b[

registry=[study.jakarta.commons.digester.ChartConfig@1aa57fb[

id=BarChart1

legendVisible=false

type=中国

width=500

description=11

], study.jakarta.commons.digester.ChartConfig@763f5d[

id=BarChart2

legendVisible=true

type=美国

width=500

description=22

]]

]

======================= getChartRegistryWithCodeRule ==========================

study.jakarta.commons.digester.ChartRegistry@18f6235[

registry=[study.jakarta.commons.digester.ChartConfig@78a212[

id=BarChart1

legendVisible=false

type=中国

width=500

description=11

], study.jakarta.commons.digester.ChartConfig@1d85f79[

id=BarChart2

legendVisible=true

type=美国

width=500

description=22

]]

]

刚学，未免存在不当的地方，欢迎指正，交流。

posted on 2007-05-23 15:00 三告习习阅读(5271) 评论(2) 编辑收藏所属分类: Jakarta

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