Notes by Fang
Displaying notes 41 - 50
Created by Fang on February 28, 2012 11:36:22
Last update: February 28, 2012 11:36:22
To set a CSS property:
$('div.left').css('position', 'absolute');
To clear the property:
$('div.left').css('position', '');
Created by Fang on February 27, 2012 13:23:14
Last update: February 27, 2012 13:23:14
For Jackson 1.7 and above:
// import org.codehaus.jackson.map.ObjectMapper;
...
For Jackson 1.6 and below:
// import org.codehaus.jackson.map.ObjectMapper;
...
Created by Fang on February 27, 2012 12:19:19
Last update: February 27, 2012 12:19:19
Mapping Java objects to Jackson JSON is pretty simple. But if you name a JSON field wrong, you'll get the "Unrecognized field ... (Class ...), not marked as ignorable" error. The rule for mapping a Java bean attribute name to a JSON field name is: lower all leading capital letters until the first lower case letter .
For example, this Java class:
package com.example;
public class Person {
...
maps to this JSON string:
{
"firstName": "Jane",
"lastName": "...
Test code:
package com.example;
import java.net.URL;
...
Created by Fang on February 21, 2012 20:54:23
Last update: February 21, 2012 20:57:57
Tomcat gzip compression filter can be turned on with " compression=on " in server.xml :
<Connector port="8080" protocol="HTTP/1.1"
...
The default compressed MIME types are: text/html,text/xml,text/plain .
It would be nice to add other types:
<Connector
port="8080"
protocol="HTT...
Created by Fang on February 21, 2012 20:33:58
Last update: February 21, 2012 20:33:58
You can customize Tomcat error page with error code:
<error-page>
<error-code>404</error-code>
...
or Java exception type:
<error-page>
<exception-type>java.lang.Throwab...
Either error-code or exception-type is required, but not both. There's no way to aggregate error codes, such as:
<!-- This does not work! -->
<error-page>
...
Customizing error pages is about the only way to suppress the default stack trace in Tomcat in case of an unhandled exception.
Created by Fang on February 17, 2012 14:35:25
Last update: February 17, 2012 14:36:25
Javadoc for javax.validation.Validation gives three ways to bootstrap JSR303 validation:
Build default validator factory:
ValidatorFactory factory = Validation.buildDefault...
The logic for buildDefaultValidatorFactory is:
if XML configuration ( META-INF/validation.xml ) defines a provider, use it.
if XML configuration does not exist or does not define a provider, use the first provider returned by ValidationProviderResolver .
Use custom ValidationProviderResolver :
Configuration<?> configuration = Validation
...
Ask for a specific provider by class:
EXAMPLEConfiguration configuration = Validation
...
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 February 15, 2012 21:26:46
Last update: February 15, 2012 21:26:46
Add configuration variables for the surefire plugin to use system properties in Maven test:
<build>
<plugins>
<plugin>
<group...
Created by Fang on February 15, 2012 21:11:02
Last update: February 15, 2012 21:11:02
Error:
java.lang.NoClassDefFoundError: org/slf4j/helpers/...
Cause: had slf4j-nop as dependency, but did not have slf4j-api.
Solution: add dependency for slf4j-api.
<dependency>
<groupId>org.slf4j</groupId>
...
Created by Fang on February 15, 2012 21:03:57
Last update: February 15, 2012 21:03:57
Error:
java.lang.NoClassDefFoundError: org/slf4j/impl/Sta...
Soluton: add Maven dependency for one of slf4j-nop , slf4j-simple , slf4j-log4j12 , slf4j-jdk14 . For example:
<dependency>
<groupId>org.slf4j</groupId>
...
or
<dependency>
<groupId>org.slf4j</groupId>
...
