使用Digester解析XML配置文件

从XML到Java对象

在Java项目中经常使用XML配置文件管理后台应用规则、实现程序初始化等操作。Digester便是专门用于从XML映射到Java对象的开源组件。它最初起源于大名鼎鼎的Struts，用于其中的配置解析工作。后来考虑到其实用性，便将其提取为独立的Apache项目，即Digester。

示例1
有如下XML（config.xml）：

<root> <parent pname="p1"> <child cname="c1">child1</child> <child cname="c2">child2</child> </parent> </root>

将其转化为如下对象：

Parent.java

Child.java

package com.vc.digester; import java.util.ArrayList; import java.util.List; public class Parent { private String name; private List<Child> childs; public String getName() { return name; } public void setName(String name) { this.name = name; } public List<Child> getChilds() { return childs; } public void setChilds(List<Child> childs) { this.childs = childs; } public void addChild(Child c){ if(childs==null)childs=new ArrayList<Child>(); childs.add(c); } }

package com.vc.digester; public class Child { private String name; private String value; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getValue() { return value; } public void setValue(String value) { this.value = value; } }

解析方法1：

TestConfig1.java

package com.vc.digester; import java.util.ArrayList; import java.util.List; import org.apache.commons.digester.Digester; public class TestConfig1 { /** * @param args */ public static void main(String[] args) { Digester digester=new Digester(); //digester.setValidating(false); digester.addObjectCreate("root",ArrayList.class);//create an ArrayList when got a ‘/root’ element digester.addObjectCreate("root/parent", Parent.class); digester.addObjectCreate("root/parent/child", Child.class); digester.addSetProperties("root/parent", "pname","name"); digester.addSetProperties("root/parent/child","cname","name");//set propertiy:cname to Child.name digester.addBeanPropertySetter("root/parent/child","value");//set node value to Child.value digester.addSetNext("root/parent", "add");//use add() method of List digester.addSetNext("root/parent/child","addChild"); try { List<Parent> parents=(ArrayList<Parent>) digester.parse("C:/ config.xml"); System.out.println(parents.get(0)); } catch (Exception e) { e.printStackTrace(); } } }

附：
HomePage：http://commons.apache.org/digester/
Download src and binaries：http://commons.apache.org/digester/download_digester.cgi