本文主要是关于使用commons-betwixt组件实现xml信息到Java Bean的转化的一些感受，实现这一功能的核心类是BeanReader，如果你看过betwixt的源代码，你会发现
public class BeanReader extends Digester{}
如果你细看一下BeanReader的源代码，betwixt在处理xml-->JavaBean转化时其实是调用Digester这个类的parse方法。但除了此方式可以实现转化的功能以外，BeanReader自身也有一些新的机制对xml进行转化，完善了Digester的很多欠缺功能,让转化更加方便。
首先，来看一下BeanReader完全使用Digester的parse方法进行转化的流程。(其实觉得说是Digester怎样处理转化更为恰当)
1。xml信息
<address-book>
<person id="1" category="acquaintance" try="would be ignored">
<name>Gonzo</name>
<email type="business">gonzo@muppets.com</email>
<gender result="the whole tag would be ignored">male</gender>
</person>
<person id="2" category="rolemodel">
<name>Kermit</name>
<email type="business">kermit@muppets.com</email>
<email type="home">kermie@acme.com</email>
</person>
</address-book>
<person id="1" category="acquaintance" try="would be ignored">
<name>Gonzo</name>
<email type="business">gonzo@muppets.com</email>
<gender result="the whole tag would be ignored">male</gender>
</person>
<person id="2" category="rolemodel">
<name>Kermit</name>
<email type="business">kermit@muppets.com</email>
<email type="home">kermie@acme.com</email>
</person>
</address-book>
2。定义实体对象Person和AddressBook
import java.util.HashMap;
import java.util.Iterator;
public class Person {
private int id;
private String category;
private String name;
private HashMap emails = new HashMap();
/**
* A unique id for this person. Note that the Digester automatically
* converts the id to an integer.
*/
public void setId(int id) {
this.id = id;
}
public void setCategory(String category) {
this.category = category;
}
public void setName(String name) {
this.name = name;
}
/** we assume only one email of each type... */
public void addEmail(String type, String address) {
emails.put(type, address);
}
public void print() {
System.out.println("Person #" + id);
System.out.println(" category=" + category);
System.out.println(" name=" + name);
for(Iterator i = emails.keySet().iterator(); i.hasNext(); ) {
String type = (String) i.next();
String address = (String) emails.get(type);
System.out.println(" email (type " + type + ") : " + address);
}
}
import java.util.Iterator;
public class Person {
private int id;
private String category;
private String name;
private HashMap emails = new HashMap();
/**
* A unique id for this person. Note that the Digester automatically
* converts the id to an integer.
*/
public void setId(int id) {
this.id = id;
}
public void setCategory(String category) {
this.category = category;
}
public void setName(String name) {
this.name = name;
}
/** we assume only one email of each type... */
public void addEmail(String type, String address) {
emails.put(type, address);
}
public void print() {
System.out.println("Person #" + id);
System.out.println(" category=" + category);
System.out.println(" name=" + name);
for(Iterator i = emails.keySet().iterator(); i.hasNext(); ) {
String type = (String) i.next();
String address = (String) emails.get(type);
System.out.println(" email (type " + type + ") : " + address);
}
}
