使用反射机制恢复xml文件表示的对象

题目：

完成如下功能：

1)有一个(任意)对象，里面有N个properties以及getter和setter方法

2)有一个properties文件，有N个key,value来描述对象中property的值

3)有一个scheme固定的xml，用来描述这个对象

要求写一个解析器：

1)将xml中的占位符，替换为properties文件中的value

2) 将xml解析成对象，调用getter方法的时候可以获得值

3)用面向对象的思想，使该解析器有扩展性

例子见附件，注意：

1)对象是任意对象，不是例子中的Student，对象中的property都是java中的原生类型

2)xml和properties在使用的时候都是根据对象配置好的

3) xml的scheme是固定的，就是附件中的scheme

Student.java文件

import java.util.Date;

/**
* Created by IntelliJ IDEA.
* User: liuzz
* Date: 13-11-2
* Time: 下午11:53
*/
public class Student {

private String name;

private int age;

private Date birth;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

public Date getBirth() {
return birth;
}

public void setBirth(Date birth) {
this.birth = birth;
}
public String toString(){
return "[ name = " + name +" , age = "+age+" , birth = " + birth+"]";
}
}

object.properties2文件

name=a
age=10
birth=2003-11-04

object.xml文件

<object class="MyTest.MyTest.Week2.Student">
<property name="name">
<value>${name}</value>
</property>
<property name="age">
<value>${age}</value>
</property>
<property name="birth">
<value>${birth}</value>
</property>
</object>

代码实现：

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.AnnotatedType;
import java.lang.reflect.Field;
import java.sql.Date;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;
import java.util.Scanner;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import com.google.common.io.Files;

public class RecoverObject<O> {
private String propertiesFile;
private String objectXmlFile;
private String recoverObjextXmlFile;
private String clazzName;
private Properties properties;
public RecoverObject(String propertiesFile, String objectXmlFile){
this.propertiesFile = propertiesFile;
this.objectXmlFile = objectXmlFile;
this.recoverObjextXmlFile = this.objectXmlFile+".recover";

this.properties = new Properties();
initObject();
}
private void processXmlFile(String context){
int pre = -1, s = -1, e = -1;
StringBuffer buffer = new StringBuffer();
while((s = context.indexOf("${", pre+1))!=-1){
e = context.indexOf("}", s + 2);
buffer.append(context.substring(pre+1, s));
String attr = context.substring(s+2, e);
buffer.append(this.properties.get(attr));
pre = e;
}
buffer.append(context.substring(pre+1));
try {
Files.write(buffer.toString().getBytes(), new File(this.recoverObjextXmlFile));
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}

}
private void initObject(){
FileInputStream in;
try {
in = new FileInputStream(new File(this.propertiesFile));
this.properties.load(in);
in.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
StringBuffer buffer = new StringBuffer();
try {
Scanner scan = new Scanner(new FileInputStream(new File(this.objectXmlFile)));
while(scan.hasNextLine()){
buffer.append(scan.nextLine());
buffer.append("\n");
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String context = buffer.toString();
this.processXmlFile(context);

}

public O get(){
SAXBuilder builder=new SAXBuilder(false);
Class<?> demo=null;
try {
Document doc=builder.build(this.recoverObjextXmlFile);
Element object=doc.getRootElement();
this.clazzName = object.getAttributeValue("class");
demo=Class.forName(this.clazzName);
O o = (O) demo.newInstance();
List propertiesList = object.getChildren("property");
for(Iterator iter = propertiesList.iterator(); iter.hasNext();){
Element attr = (Element) iter.next();
String attrName = attr.getAttributeValue("name");
String attrValue = attr.getChildText("value");
Field f= demo.getDeclaredField(attrName);
f.setAccessible(true);
Class<?> type = f.getType();
if(type.equals(String.class)){
f.set(o, attrValue);
}else if(type.equals(int.class)){
f.set(o, Integer.parseInt(attrValue));
}else if(type.equals(java.util.Date.class)){
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
f.set(o, format.parse(attrValue));
}

}
return o;
} catch (JDOMException e) {

e.printStackTrace();
} catch (IOException e) {

e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchFieldException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

return null;
}
public static void main(String [] args){
RecoverObject<Student> object = new RecoverObject<Student>("./source/object.properties2", "./source/object.xml");
Student s = object.get();
System.out.println(s);
}
}