Common Digester附帶了一個插件機制，可以實現很好的地址，下面是我的一個簡單實現：
1、業務接口：
public interface Transform 
{
public String transform(String s);
}
2、業務接口的實現類：
public class CaseTransformer implements Transform {
private boolean upper;
public void setCase(String s) {
upper = "upper".equalsIgnoreCase(s.trim());
}
public String transform(String s) {
if (s == null) {
return "";
}
return upper ? s.toUpperCase() : s.toLowerCase();
}
}
3、插件創建規則：
package mydigest;
import org.xml.sax.Attributes;
public class MyPluginCreateRule extends MyRule {
private Class<?> baseClass;
public static final String DEFT_PLUGIN_CLASS_ATTR = "plugin-class";
public MyPluginCreateRule(Class<?> clazz) {
baseClass = clazz;
}
/** *//** 開始處理 */
public void begin(String namespace, String name, Attributes attributes) throws Exception {
String value = attributes.getValue(DEFT_PLUGIN_CLASS_ATTR);
Class<?> clazz = dig.getClassLoader().loadClass(value);
Object instance = clazz.newInstance();
if (baseClass.isAssignableFrom(clazz)) {
dig.push(instance);
}
}
/** *//** 處理結束 */
public void end(String namespace, String name) throws Exception {
dig.pop();
}
}
4、配置文件upperconfig.xml：
<piple>
<src file="input.txt"/>
<transform plugin-class="mydigest.CaseTransformer" case="upper"/>
<dest file="output.txt"/>
</piple>
5、測試：
package mydigest;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
public class Piple {
private String src;
private Transform transformer;
private String dest;
public static void main(String[] args) {
String file = "upperconfig.xml";
MyDigester dig = new MyDigester();
dig.addObjectCreate("piple", Piple.class);
// 源文件
dig.addCallMethod("piple/src", "setSrc", 1);
dig.addCallParam("piple/src", 0, "file");
// 添加插件
MyPluginCreateRule pcr = new MyPluginCreateRule(Transform.class);
dig.addRule("piple/transform", pcr);
dig.addSetProperties("piple/transform");
dig.addSetNext("piple/transform", "setTransform");
// 目標文件
dig.addCallMethod("piple/dest", "setDest", 1);
dig.addCallParam("piple/dest", 0, "file");
try {
Piple piple = (Piple) dig.parse(new File(file));
piple.exec();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void setSrc(String src) {
this.src = src;
}
public void setTransform(Transform transformer) {
this.transformer = transformer;
}
public void setDest(String dest) {
this.dest = dest;
}
public void exec() throws IOException {
BufferedReader reader = new BufferedReader(new FileReader(src));
FileWriter writer = new FileWriter(new File(dest));
String line = reader.readLine();
while (line != null) {
writer.write(this.transformer.transform(line) + '\n');
line = reader.readLine();
}
writer.close();
reader.close();
System.out.println("exec done!");
}
}
inut.txt文件：
Copyright
Copyright 2004 O'Reilly Media, Inc.
Printed in the United States of America.
Published by O'Reilly MediaInc., 1005 Gravenstein Highway North, Sebastopol, CA 95472.
得到的output.xml文件：
COPYRIGHT
COPYRIGHT 2004 O'REILLY MEDIA, INC.
PRINTED IN THE UNITED STATES OF AMERICA.
PUBLISHED BY O'REILLY MEDIAINC., 1005 GRAVENSTEIN HIGHWAY NORTH, SEBASTOPOL, CA 95472.