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Created by Fang on March 05, 2012 20:11:56
Last update: March 05, 2012 20:11:56
This is a bare bones Maven project to get started with Java JSR 303 bean validation.
Directory structure:
./pom.xml
./src
./src/main
./src/main/jav...
pom.xml :
<project xmlns="http://maven.apache.org/POM/4.0.0"...
which includes dependencies on JUnit, Java bean validation API and the Hibernate validator reference implementation.
Created by Dr. Xi on February 13, 2012 20:48:56
Last update: February 13, 2012 20:48:56
When you insert an attribute in JSP:
<%@ taglib uri="http://tiles.apache.org/tags-tiles...
you must define the attribute in tiles definitions:
<definition name="/home" template="/WEB-INF/templa...
Otherwise you'll get runtime exception.
The ignore attribute, which defaults to false , will suppress the runtime exception when the attribute is not defined in tiles definition:
<%@ taglib uri="http://tiles.apache.org/tags-tiles...
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 nogeek on December 30, 2011 13:54:04
Last update: December 30, 2011 13:54:04
Tomcat 7.0 failed with a SEVERE error without printing a stack trace:
Dec 30, 2011 1:21:09 PM org.apache.catalina.core.S...
Now it's hard to figure out what's wrong without knowing where things went wrong. Why is Tomcat not logging anything?
Tomcat logging is configured by class loader. Logging behaves differently depending on which class loader loaded the logger. You'll need to look at both $CATALINA_BASE/conf/logging.properties and WEB-INF/classes/logging.properties to figure out why the stack trace is not logged.
In my case, the web app specific WEB-INF/classes/logging.properties overshadowed the system $CATALINA_BASE/conf/logging.properties and suppressed the stack trace.
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 10, 2011 20:33:46
Last update: November 10, 2011 20:33:46
The stack trace is like this:
java.lang.IllegalArgumentException: Component prop...
You get this error because you are using the class attribute with a JSF UI component, for which the class attribute cannot be altered. Of course you meant CSS class, not Java class! You can use the styleClass attribute instead of the class attribute. The styleClass attribute becomes the class attribute when the component is rendered.
If you can add a tag handler to the UI component, you can alias class to styleClass , which will allow you to use the class attribute on the UI component:
import javax.faces.view.facelets.*;
pub...
Created by Fang on October 28, 2011 13:49:40
Last update: October 30, 2011 19:23:25
This is a simple example to demonstrate the templating power of JSF facelets. If you've used struts tiles before, you'll recognize the simplicity of templating with facelets. I've stripped out everything else except the pages themselves, just to put our focus on facelets. This is a Maven based project, and you need Tomcat (or any servlet container) to run the resulting webapp. To begin with this is the list of files:
./pom.xml ./src/main/webapp/home.xhtml ./src... I left faces-config.xml in there for completeness sake, it may not be needed. The Maven POM ( pom.xml ): <?xml version="1.0" encoding="UTF-8"?> <project... Web app configuration ( WEB-INF/web.xml ): <?xml version="1.0" encoding="UTF-8"?> <web-app... Empty WEB-INF/faces-config.xml : <?xml version="1.0" encoding="UTF-8"?> <!-- Thi... index.jsp is simply a redirect to home.jsf : <% response.sendRedirect("home.jsf"); %>...
Created by Fang on October 22, 2011 19:51:05
Last update: October 22, 2011 20:31:48
I built a very basic JSF application and deployed to Tomcat 7.0.22, but it failed with this error:
Caused by: java.lang.ClassFormatError: Absent Code... That looks weird and I wasn't able to find a sensible explanation! So I copied the jsf-api-2.1.jar , which was downloaded from the java.net Maven repository by Maven, into a temp folder. And tested it with this simple program: public class ClassFormatErrorTest { public ... I also copied servlet-api.jar from Tomcat's lib folder to the temp folder. Sure enough it failed with the same error: C:\tmp>java -cp .;jsf-api-2.1.jar;servlet-api.jar ... But when I replaced the javax.faces.webapp.FacesServlet class with one I compiled from source, the error disappears! Conclusions: The jar file jsf-api-2.1.jar from java.net Maven repository is good for compilation only (cannot be used...
Created by Dr. Xi on March 24, 2011 12:11:14
Last update: March 24, 2011 12:22:03
This is the task: your client wants to know how the web application is used. That is pretty easy. A plethora of commercial tools or any of the free log analysis tools such as analog and AWStats would fit the bill. But here's the catch: they want to know not only what pages are visited by how many people and when, but also who logged in and did what. Your application is using form based authentication and therefore, everyone is anonymous in the web access log. What to do? This is a servlet filter that generates a web access log with authenticated user info that can be fed to log analysis tools such as analog and AWStats . Filter code (the output format is Apache...
Created by nogeek on February 03, 2011 13:08:38
Last update: February 03, 2011 13:14:10
The log line was like this:
2011-01-19 15:16:34,842 INFO [STDOUT] (HDScanne... Note that INFO and timestamp were printed twice. Based on my configuration, I was expecting something like this: 2011-01-19 15:16:34,842 INFO [XmlWebApplicationC... i.e., the logger name should have been XmlWebApplicationContext , not STDOUT ! What was the problem? I found this error message in server.log : 2011-01-19 14:34:38,107 ERROR [STDERR] (main) lo... It turned out that org.apache.log4j.Appender was loaded by my web application class loader, whereas org.jboss.logging.appender.FileAppender was loaded by the JBoss bootstrap class loader. Removing the log4j jar from my web application archive fixed the problem (sine log4j is already available in JBoss). Why was the logger changed to STDOUT? JBoss detects that there's a problem with the log4j configuration and routes all...