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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" ?><charts> <chart id="BarChart1"> <legendVisible>false</legendVisible> <type>中国</type> <width>500</width> <description>11</description> </chart> <chart id="BarChart2"> <legendVisible>true</legendVisible> <type>美国</type> <width>500</width> <description>22</description> </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> <pattern value="charts"> <!-- 遇上charts节点时 --> <object-create-rule classname="study.jakarta.commons.digester.ChartRegistry" /> <!-- 创建对象 --> <set-properties-rule /> <!-- 设置属性 --> <pattern value="chart"> <!-- 遇上charts节点时 --> <object-create-rule classname="study.jakarta.commons.digester.ChartConfig" /> <!-- 创建对象 --> <set-next-rule methodname="addChart" paramtype="study.jakarta.commons.digester.ChartConfig"/> <!-- 调用定对象方法 --> <set-properties-rule /> <!-- 设置属性 --> <bean-property-setter-rule pattern="legendVisible" /> <!-- 调用对象的setter方法 --> <bean-property-setter-rule pattern="type" /> <bean-property-setter-rule pattern="width" /> <bean-property-setter-rule pattern="description" /> </pattern> </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。 |
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来自： goldbomb > 《Digester》
