Notes by Fang
Displaying notes 31 - 40
Created by Fang on March 06, 2012 12:25:33
Last update: March 06, 2012 12:25:33
In the bean validation API javadoc, for every constraint annotation, there's a corresponding .List annotation. For example, for @NotNull , there's @NotNull.List , for which JavaDoc says: Defines several @NotNull annotations on the same element What would you accomplish with multiple @NotNull annotations that you cannot accomplish with one @NotNull ? This is a test to reveal some of the facts. Change the Person class to:
package com.example; public class Person { ... Add another JUnit test ( src/test/com/example/TestPersonWithList.java ): package com.example; import java.util.Itera... As the test shows, a Person bean can never be valid because we are requiring that name must begin with Mr and Ms . One might think that the same can be accomplished by simply repeating the @Pattern annotation multiple times,...
Created by Fang on March 06, 2012 12:24:53
Last update: March 06, 2012 12:24:53
Validation groups can be used to control which rules validation rules to run. A validation group can be identified by any Java interface (not class!). Multiple validation groups may be specified when validating.
In this example, I added a validation group named MyValidationGroup ( src/main/java/com/example/MyValidationGroup.java in Maven project):
package com.example;
public interface MyVal...
and added a @Size rule for a person's name, because my database can only store up to 15 characters for a person's name:
package com.example;
import javax.validatio...
Now validate Person with a JUnit test ( src/test/java/com/example/TestPersonWithGroup.java in Maven project):
package com.example;
import java.util.Set;
...
Test with " mvn clean test ". The rules where groups is not specified, which belong to the javax.validation.groups.Default group, are not executed with these tests.
Created by Fang on March 06, 2012 12:24:05
Last update: March 06, 2012 12:24:05
A bean class may also be defined through composition. The validation rules of referenced beans are not automatically called when a composite bean is validated. You need to use the @Valid annotation to trigger cascade validation.
As an example, I create a class named AccountPerson2 , which contains a Person with the addition of an email field ( src/main/java/com/example/AccountPerson2.java in Maven project):
package com.example;
import javax.validatio...
Now validate AccountPerson2 with a JUnit test ( src/test/java/com/example/AccountPerson2Test.java in Maven project):
package com.example;
import java.util.Set;
...
Test with " mvn clean test " and you'll see that the validation rules of the Person class are executed when an AccountPerson2 bean is validated. Without the @Valid annotation, the validation rules of Person will not be called.
Created by Fang on March 06, 2012 12:22:48
Last update: March 06, 2012 12:22:48
When a bean class inherits another class, the validation rules of the parent class is automatically executed when a child class bean is validated.
As an example, I create a class named AccountPerson , which inherits the Person class with the addition of an email field ( src/main/java/com/example/AccountPerson.java in Maven project):
package com.example;
import javax.validatio...
Now validate AccountPerson with a JUnit test ( src/test/java/com/example/AccountPersonTest.java in Maven project):
package com.example;
import java.util.Set;
...
Test with " mvn clean test " and you'll see that the validation rules of the Person class are executed when an AccountPerson bean is validated.
Created by Fang on March 05, 2012 20:32:37
Last update: March 05, 2012 20:32:37
In this simple example, I create a simple validating bean and create a JUnit test to test the validation.
The bean ( src/main/java/com/example/Person.java ):
package com.example;
import javax.validatio...
The test ( src/test/java/com/example/TestPerson.java ):
package com.example;
import java.util.Set;
...
Run the test:
mvn clean test
You'll notice that one test passed and the other failed.
The tests require that a person must have a name and the name cannot be empty, so @NotNull is not the right rule to use here. To make sure that the name is not empty, we need to use @Pattern . But since a null String matches any pattern, @NotNull is also needed:
package com.example;
import javax.validatio...
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 Fang on March 02, 2012 13:23:35
Last update: March 02, 2012 13:23:35
The landing page after login can be configured with the default-target-url attribute of form-login . If a user was redirected to the login form after requesting a restricted URL, she's redirected to the original requested page after successful login.
An easy configuration looks like this:
<beans:beans xmlns="http://www.springframework.org...
But there are times that you want to do more initialization after login (such as loading user data), or apply more complex logic before redirecting. This is where the authentication-success-handler-ref attribute comes into play. You create a class that implements org.springframework.security.web.authentication.AuthenticationSuccessHandler and use that as the authentication-success-handler-ref :
<http
entry-point-ref="authProcessFilterEn...
This is a skeleton implementation:
public class MyAuthenticationSuccessHandler implem...
Created by Fang on February 23, 2012 14:25:57
Last update: March 01, 2012 13:53:59
Some example snippets for Spring message configuration and usage.
To configure a message source in Spring context (basename=messages):
<bean id="messageSource"
class="org.springf...
Locale change interceptor can also be setup with:
<?xml version="1.0" encoding="UTF-8"?>
<beans x...
The messages file should be named messages.properties (or messages_en.properties , etc.) and located on CLASSPATH , for example: WEB-INF/classes .
To use a message resource in JSP:
<%@ taglib prefix="spring" uri="http://www.springf...
Created by Fang on March 01, 2012 13:52:14
Last update: March 01, 2012 13:52:14
Step 1: define the message code:
code.with.arg=arg1: {0}, arg2: {1}, arg3: {2}
Step 2: use it in the JSP with comma separated arguments:
<%@ taglib uri="http://www.springframework.org/tag...
If the argument itself contains a comma:
<%@ taglib uri="http://www.springframework.org/tag...
Created by Fang on February 29, 2012 15:11:22
Last update: February 29, 2012 15:11:22
There are two types of application contexts with Spring MVC: the root context created by ContextLoaderListener , and contexts associated with each DispatcherServlet . According to the Spring Javadoc :
A web application can define any number of DispatcherServlets. Each servlet will operate in its own namespace, loading its own application context with mappings, handlers, etc. Only the root application context as loaded by ContextLoaderListener, if any, will be shared.
