Base64 XML JDom 实例
问题：如何将二进制存入XML 然后传输倒别的地方，然后将其取出呢？
解答。我们写一段程序。
思路，
1 将图片存进XML文档的方式
答：将图片利用Base64编码成字符串形式，然后通过JDOM存储进XML
2 将图片从XML取出
答：通过ＪＤＯＭ取出图片编码的字符串，然后通过Base64解码成二进制形式
所以我们可以归纳出三个类
FileBase64.java 负责编码解码图片
ParseXML.java 读取XML文档，读出图片的字符串，解码成图片
OutputXML.java 将图片编码成字符串并放进XML文档
下面是源码。注释已经相当于讲解。
package www.websiteempire.cn;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
/*
* 两个方法，binaryToString一个是将二进制编码成字符串的方法，其中MessageDigest是消息摘要
* 可要可不要。核心方法是使用BASE64Encoder的 方法对数据惊醒编码。
* 同理stringToBinary
*/
public class FileBase64
{
public static int MAX_BUFFER_SIZE = 524288; // default 512 kB
private int maxBufferSize = MAX_BUFFER_SIZE;
private String md5sum = null;
private int fileLength = -1;
public String fileToString(String path, String name)
{
return null;
}
public String binaryToString(String path) throws IOException
{
File fm = new File(path);
if (fm.isFile())
{
InputStream in = null;
String ss = new String();
MessageDigest md = null;
try
{
in = new FileInputStream(fm);
md = MessageDigest.getInstance("MD5");
byte[] Buffer = new byte[maxBufferSize];
int read = 0;
int fileLength = 0;
while ((read = in.read(Buffer)) != -1)
{
fileLength += read;
md.update(Buffer, 0, read);
if (read < maxBufferSize)
{
byte[] buf = new byte[read];
System.arraycopy(Buffer, 0, buf, 0,
read);
Buffer = buf;
}
ss += new BASE64Encoder().encode(Buffer) + " ";
}
md5sum = new BASE64Encoder().encode(md.digest());
return ss;
} catch (FileNotFoundException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchAlgorithmException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
finally
{
try
{
if (in != null) in.close();
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
return null;
}
public boolean stringToBinary(String path,String data)
{
OutputStream os=null;
try
{
os=new FileOutputStream(new File(path));
byte[] buf = new BASE64Decoder().decodeBuffer(data);
MessageDigest md=MessageDigest.getInstance("md5");
fileLength=-1;
md5sum = null;
if (buf != null)
{
os.write(buf);
fileLength = buf.length;
md5sum = new BASE64Encoder().encode(md.digest(buf));
}
else return false;
return true;
} catch (FileNotFoundException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchAlgorithmException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
finally
{
try
{
if (os != null) os.close();
}
catch (Exception e)
{
e.printStackTrace();
}
}
return false;
}
public int getMaxBufferSize()
{
return maxBufferSize;
}
public void setMaxBufferSize(int maxBufferSize)
{
this.maxBufferSize = maxBufferSize;
}
public String getMd5sum()
{
return md5sum;
}
public void setMd5sum(String md5sum)
{
this.md5sum = md5sum;
}
public int getFileLength()
{
return fileLength;
}
public void setFileLength(int fileLength)
{
this.fileLength = fileLength;
}
//main test
// public static void main(String[] args)
// {
// String path="G://workspace//software//src//splash.jpg";
// FileBase64 fb=new FileBase64();
// String temp=null;
// try
// {
// temp=fb.fileToString(path);
// } catch (IOException e)
// {
// // TODO Auto-generated catch block
// e.printStackTrace();
// }
// System.out.println(temp);
//// try
//// {
//// FileOutputStream fos=new FileOutputStream(new File("e:/splash.txt"));
//// fos.write(temp.getBytes());
//// fos.close();
//// } catch (FileNotFoundException e)
//// {
//// // TODO Auto-generated catch block
//// e.printStackTrace();
//// }
////// System.out.println(fb.getFileLength());
////// System.out.println(fb.getMd5sum());
////// fb.stringToFile("e://splash.jpg", temp);
//// catch (IOException e)
//// {
//// // TODO Auto-generated catch block
//// e.printStackTrace();
//// }
////
// }
}
_---------------------------------------------------------------
package www.websiteempire.cn;
import java.io.IOException;
import java.util.List;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;
public class ParseXML
{
/**
* @param args这个文件比较简单就是读取XML文件并且输出图片
*/
public static void main(String[] args)
{
try
{
SAXBuilder parser=new SAXBuilder();
Document document=parser.build("e:/cc.xml");
process(document.getRootElement());
} catch (JDOMException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void process(Element element)
{
Element img=element.getChild("img");
String temp=img.getText();
String path="e:/cc.jpg";
FileBase64 fb=new FileBase64();
fb.stringToBinary(path,temp);
}
}
---------------------------------------------------------------------
package www.websiteempire.cn;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.sql.Date;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.output.XMLOutputter;
public class OutputXML
{
/**
* 这段是测试代码。你可以根据你的要求自己写一个。为了测试效果，你可以
* 直接修改路径
*
*/
public static void main(String[] args)
{
String path="e:/cc.jpg";
FileBase64 fb=new FileBase64();
OutputXML outputXml=new OutputXML();
String temp=null;
try
{
temp=fb.binaryToString(path);
} catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
String img=temp;
String description="you can ";
Date CDate=new Date(System.currentTimeMillis());
String ower="websiteempire.cn";
Document doc=outputXml.constructXML(img, description, CDate, ower);
outputXml.WriteXML(doc, "e:/cc.xml");
}
/*
* 这段代码主要是用来生成一个XML文档，其中包含的元素有 imgElement图片结点,descriptionElement描述图片的文字描述,
* CDateElment图片的穿件日期, OwerElment拥有者
*/
public Document constructXML(String img, String description,
Date CDate, String ower)
{
Element root = new Element("websiteempire_cn");
Element imgElement = new Element("img");
imgElement.setText(img);
Element descriptionElement = new Element("description");
descriptionElement.setText(description);
Element CDateElement = new Element("CDate");
CDateElement.setText(CDate.toGMTString());
Element owerElement = new Element("ower");
owerElement.setText(ower);
root.addContent(imgElement);
root.addContent(descriptionElement);
root.addContent(CDateElement);
root.addContent(owerElement);
Document doc = new Document(root);
return doc;
}
/*
* 将XML文档保存成一个文件。
*/
public void WriteXML(Document doc,String path)
{
File file=new File(path);
try
{
FileOutputStream fos=new FileOutputStream(file);
XMLOutputter out=new XMLOutputter();
out.output(doc, fos);
} catch (FileNotFoundException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}