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Created by Fang on April 16, 2012 12:58:35
Last update: April 16, 2012 12:58:35
To implement a JSP custom tag with dynamic attributes (for example, to pass-thru arbitrary attributes not handled by the JSP tag):
Set the dynamic-attributes element to true in the TLD:
<tag>
<name>mark</name>
<tag-class>c...
The tag handler must implement javax.servlet.jsp.tagext.DynamicAttributes :
package com.example.jsp;
import java.io.*;
...
Created by Fang on February 16, 2012 12:27:55
Last update: February 16, 2012 12:34:58
Here are some ways to run a main method using Maven:
Use the exec plugin:
mvn exec:java -Dexec.mainClass="com.example.App"
or, with arguments:
mvn exec:java -Dexec.mainClass="com.example.App" -...
Attach it to a build phase with the build element:
<build>
<plugins>
<plugin>
...
If you want to run main from Maven, it's probably just some test code. You are better off just to write a test case, or call the main method from a test class:
package com.example;
import junit.framework...
Created by Fang on January 28, 2012 13:24:09
Last update: January 28, 2012 13:31:22
This is a simple JSP custom tags library with tag body. Just like the JSF counterpart , it splits a string and repeats the body for each word, i.e., with this markup:
<%@ taglib uri="http://custom.tag.com/demo" prefix...
output:
<html>
<body>
<p>Hello Tigger!</p>
<p>H...
With Maven, this is the directory structure:
./src
./src/main
./src/main/resources
./s...
There are three files to write:
pom.xml :
<project xmlns="http://maven.apache.org/POM/4.0.0"...
src/main/java/tagdemo/IterateTag.java :
package tagdemo;
import java.io.IOException...
src/main/resources/META-INF/demotag.tld :
<?xml version="1.0" encoding="UTF-8"?>
<!DO...
Build with:
mvn clean install
To use it as a dependency in other Maven projects:
<dependency>
<groupId>tag-demo</groupId>
...
Created by zhidao on January 25, 2012 19:27:53
Last update: January 25, 2012 19:28:47
The spring MVC annotation-driven declaration:
<?xml version="1.0" encoding="UTF-8"?> <beans x... does the following magic : Among others, registers: RequestMappingHandlerMapping RequestMappingHandlerAdapter ExceptionHandlerExceptionResolver in support of processing requests with annotated controller methods using annotations such as @RequestMapping , @ExceptionHandler , etc. Enables Spring 3 style type conversion through a ConversionService instance in addition to the JavaBeans PropertyEditors used for Data Binding. Enables support for formatting Number fields using the @NumberFormat annotation through the ConversionService . Enables support for formatting Date, Calendar, Long, and Joda Time fields using the @DateTimeFormat annotation, if Joda Time 1.3 or higher is present on the classpath. Enables support for validating @Controller inputs with @Valid , if a JSR-303 Provider is present on the classpath. Enables HttpMessageConverter support for @RequestBody method parameters and...
Created by lokf on January 13, 2012 14:10:42
Last update: January 13, 2012 14:10:42
For some reason I don't know writing to files in Android is very complicated and tedious. Here is some code for those who might need it. Apps should write in the SD in the directory /Android/data/package_name/files/ so that it is deleted with the app uninstall. package randomname; import java.io.BufferedOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.FileWriter; import java.io.IOException; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.nio.ByteBuffer; import android.content.Context; import android.os.Environment; import android.util.Log; public class FileIOLibrary { String packageName; boolean mExternalStorageAvailable = false; boolean mExternalStorageWriteable = false; FileIOLibrary(String packageNamep) { this.packageName=packageNamep; } public boolean isExternalStorageAvailable() { updateExternalStorageState(); return mExternalStorageAvailable; } public boolean isExternalStorageWritable() { updateExternalStorageState(); return mExternalStorageWriteable; } /** * writes the current state of SD card to the corresponding variables */ void updateExternalStorageState() {...
Created by nogeek on December 30, 2011 13:25:28
Last update: December 30, 2011 13:57:37
By default, tomcat uses an enhanced java.util.logging implementation called JULI, which can be configured at two different levels: Globally, with the ${catalina.base}/conf/logging.properties file. Per web application, with WEB-INF/classes/logging.properties . The configuration file is a normal Java properties file: Logging handlers are specified with the handlers property.
handlers = 1catalina.org.apache.juli.FileHandler, ... The root logger can define its set of handlers using the .handlers property. .handlers = 1catalina.org.apache.juli.FileHandler,... A prefix may be added to handler names. The prefix starts with a digit and ends with a dot ( . ), for example: # 1catalina. is a prefix 1catalina.org.apache.j... System property replacement is performed for property values which contain ${systemPropertyName} . Each handler can have its own specific properties: 3manager.org.apache.juli.FileHandler.level = FINE ... Loggers can define their own...
Created by Fang on December 06, 2011 19:03:25
Last update: December 07, 2011 08:54:11
Our custom tag, as implemented in the previous note , is broken when a template is used.
Create a template file ( home-template.xhtml ):
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Stric...
and a test page that uses it ( home.xhtml ):
<?xml version="1.0" encoding="UTF-8"?>
<ui:comp...
Then request the page with URL: http://localhost:8080/facelet-demo/home.jsf?name=Jack .
You'll find that our hello tag works inside ui:repeat but fails to get the value defined by ui:param ! What's the problem? Our hello tag implementation evaluated the EL with the wrong EL context!
This is the corrected implementation:
package com.example;
import java.io.IOExcep...
Created by Fang on November 10, 2011 13:19:13
Last update: December 01, 2011 19:10:43
You can add custom implicit variables to JSF pages by using a custom EL resolver, in two simple steps: Write an ELResolver class to resolve the variable Add the ELResolver to faces-config.xml Starting from the Maven Hello World example: Add faces API and EL dependencies to pom.xml :
<dependencies> <dependency> <groupId>o... Add a simple greeter class ( src/main/java/com/example/Greeter.java ): package com.example; public class Greeter {... Add our custom EL resolver ( src/main/java/com/example/ELResolver.java ): package com.example; import java.util.Itera... Add the custom EL resolver to src/main/resources/META-INF/faces-config.xml <?xml version="1.0" encoding="UTF-8"?> <faces-c... Build JAR with mvn package Drop the JAR into WEB-INF/lib of a webapp and test the new EL with: <h:outputText value="#{Greeter.sayHi('Mike')}"/> Fixed: the setValue method used to throw an exception, which is wrong. @Override public void setValue(ELContext ctx, O......
Created by Fang on November 21, 2011 15:57:49
Last update: November 22, 2011 09:51:26
The improved custom taglib works with existing facelet ui taglibs. For example:
<ui:param name="theName" value="John"/> <my:hel... produces the expected output. However, a problem exists with the ui:repeat tag: <h3>With ui:repeat</h3> <ui:repeat var="theName... When tested with a URL like: http://localhost:8080/facelet-demo/?name=Zack&name... the raw EL prints out the correct names, but my custom tag substitutes empty string for theName2 ! In theory, the response is rendered in the Render Response phase, way after the Apply Request Values phase, actual values should be available to EL. The answer to this anomaly turned out to be very deep ! Yes, right there in the code! I would consider this a bug in facelets implementation, but the JSF spec did not tell what the expected behavior should be. In my custom...
Created by Fang on November 21, 2011 13:49:11
Last update: November 21, 2011 13:49:11
In the test for the simple taglib example , I used a literal string for the name attribute:
<my:hello name="Jack"/> What happens if the name attribute contains EL expresson? For example: <my:hello name="#{param['name']}"/> If EL works, the tag should take the value of the " name " request parameter and print it out. But the tag as implemented in the simple taglib example prints the literal string: Hello #{param['name']}! I am FaceletTag. In order to make a tag to recognize EL, we have to use TagAttribute.getValue(FaceletContext ctx) instead of TagAttribute.getValue() . The latter returns the literal value of the attribute. The HelloTagHandler should be changed to: package com.example; import java.io.IOExcep... Rebuild the taglib and test with a URL like this: http://localhost:8080/facelet-test/?name=Jack The tag will print:...
