Recent Notes

Java swing hello world

Created by alfa on April 04, 2011 18:09:43 Last update: April 08, 2011 12:27:11

import java.awt.Graphics;
 
 import java.awt.event...

Java screen capture example code

Created by alfa on April 08, 2011 11:05:24 Last update: April 08, 2011 11:05:24

Key points: Use java.awt.Robot to capture a screen region as java.awt.image.BufferedImage . Use javax.imageio.ImageIO to write image out to a file.

import java.awt.AWTException;
 
 import java.awt.R...

Java: write XML to file with transformer

Created by nogeek on April 07, 2011 21:30:54 Last update: April 07, 2011 21:30:54

This is the opposite of parsing. You can use javax.xml.transform.Transformer to output a DOM tree to a file.

import java.io.*;
 
 import javax.xml.parsers.Docu...

Java parse xml with transformer

Created by nogeek on April 07, 2011 21:07:55 Last update: April 07, 2011 21:07:55

You can use the javax.xml.transform.Transformer class to "transform" an XML stream (string in this case) to a DOM tree - effectively parsing the XML string.

import java.io.*;
 
 import javax.xml.transform.Tr...

Java parse xml string example

Created by nogeek on April 07, 2011 20:54:17 Last update: April 07, 2011 20:54:17

Use javax.xml.parsers.DocumentBuilder to parse xml. DocumentBuilder.parse() takes: java.io.File org.xml.sax.InputSource java.io.InputStream java.lang.String as a URI to an XML document Example code:

import java.io.*;
 
 import javax.xml.parsers.Docu...

Java keytool cannot print Base64 encoded pem certificate, but can import it

Created by freyo on April 06, 2011 14:50:01 Last update: April 06, 2011 15:00:03

C:\tmp>keytool -printcert -file CERT.pem
 
 keytoo...

Java file as url

Created by alfa on April 06, 2011 13:23:40 Last update: April 06, 2011 13:23:40

A file can be read as URL with the java.net package. You must provide absolute path after the URI scheme name file:// .

package com.demo.io;
 
 
 
 import java.io.*;
 
 i...

Java read file as byte array

Created by alfa on April 06, 2011 12:48:44 Last update: April 06, 2011 12:48:44

package com.demo.io;
 
 
 
 import java.io.*;
 
 
...

Java read file from classpath

Created by alfa on April 06, 2011 12:07:12 Last update: April 06, 2011 12:08:01

You can use Class.getresourceAsStream or ClassLoader.getresourceAsStream to read a file from classpath. Class.getresourceAsStream delegates to ClassLoader.getresourceAsStream , but it does some preprocessing before delegation: If the file name begins with a '/', then the absolute name of the resource is the portion of the name following the '/'. Otherwise, the absolute name is: package_name_with_dot_replaced_by_slash/file_name

package com.demo.io;
 
 
 
 import java.io.*;
 
 
...

Java HttpServletResponse getStatus with HttpServletResponseWrapper

Created by Dr. Xi on April 05, 2011 08:34:17 Last update: April 05, 2011 08:35:06

The Java servlet API does not provide a getStatus method for HttpServletResponse until version 3.0. This is a wrapper that provides getStatus for servlet API 2.5 and older. You have to override 4 methods because sendError etc. does not call setStatus .

import javax.servlet.*;
 
 import javax.servlet.ht...

You can plug it in a servlet filter like this:

public void doFilter(ServletRequest req,
 
 		    ...

Ξ Notes

Keywords