I was reading Spring in action these days and came across the following code. I'm wondering if the following code can actually work.
<property name="chosenCity" value="#{cities[T(java.lang.Math).random() * cities.size()]}"/>
It seems like
T(java.lang.Math).random() * cities.size()
will return a double value. How can we reference a double value index in a array? The author didn't explain this? I was wondering if Spring SpEL has any auto-converting mechanism to trim a double value to int?
Thanks!
Yes, SpEL will provide necessary conversions (if it can). See section 7.3.1 in the Spring Reference Manual.
Related
How to read a value from application.yml in my Micronaut project? I can clearly see annotation is resolved to proper value (true in this case), but it is not applied to the variable (stays as default false). I've tried using #Value and #ConfigurationProperties
In a comment the OP has indicated that they are doing new FeatureToggleService(). Creating your own instance of the object is the problem. Instead of using new, let the DI container create and manage the instance. If you do, then #Value will be relevant.
See https://github.com/jeffbrown/filiard/blob/f6f704fb95d7821919748bb41968f87d11cee07b/src/main/java/filiard/DemoController.java and https://github.com/jeffbrown/filiard/blob/f6f704fb95d7821919748bb41968f87d11cee07b/src/main/java/filiard/FlagHelper.java for a working example.
UPDATE:
Based on additional information this is not the correct answer!!!
As pointed out, #Value can be private, but Micronaut advices against it.
Short answer, it is because it is private. Wrong
From the documentation:
The #Value annotation accepts a string that can have embedded placeholder values (the default value can be provided by specifying a
value after the colon : character). Also try to avoid setting the
member visibility to private, since this requires Micronaut Framework
to use reflection. Prefer to use protected.
Also, consider using #Property instead of #Value. Still valid
https://docs.micronaut.io/latest/guide/#valueAnnotation
NOTE:
The Micronaut framework does not inspect a manually created instance, even if it is instantiated in a #Factory, unlike other frameworks.
I am looking for a solution for the problem where I can configure the pointcut expressions dynamically by reading from a properties file or database.
for example:
#Around("execution(* com.example.updateUser(..))")
in above example, we have hardcoded the expression.
I am looking for the solution where I can read
execution(* com.example.updateUser(..))
and then use it in #Around annotation.
I did not come across similar problem on web.
Any solution for such problem is highly appreciated.
Thank you!!
You can use schema-based AOP and define the pointcut in classical, old-school XML style. Spring XML config is a text file being read while starting up the application and thus would satisfy your requirement.
If you like to manually wire your pointcut into an aspect, you can do that, too. Whether you define a string variable or field containing the pointcut directly in your application or read the pointcut from a text file, is completely up to you. Search for the terms DefaultPointcutAdvisor and AspectJExpressionPointcut in my answer here, somewhere inside the "update 2" and "update 3" parapgraphs. There you will also find a link to a complete sample project.
I have some properties like
/my/{custom}/url
I would need to replace {custom} with some value at runtime
I know that Spring is using "#RequestMapping" with a similar syntax for #PathAttribute matching.
I'm wondering if there is some Class I can reuse from Spring to achieve what I need.
A good option for this is to use a UriComponentsBuilder - see reference here: http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/web/util/UriComponentsBuilder.html
UriComponentsBuilder.fromPath("/test/{one}/{two}").buildAndExpand(map).toUriString()
I am looking at using the Spring's Field formatting in particular the existing DateFormatter. I do understand that I need to specify a pattern on an annotation in my POJO.
Instead of hard coding the pattern I need to be able to provide it dynamically, I know this is not feasible with annotations. To properly support internationalization I would need to look up a pattern from a properties file before passing it to a Formatter.
Can anyone suggest an approach I can take?
Not sure however you may try implementing InitializingBean or init-method and set the values dynamically.
like suggested in spring forum for cron expression.
I am using Spring MVC for my web application.
I need to validate that the URL the user inputs is valid and was wondering if there is something in Spring that can do the basic checks for me (for example starts with http/https, has domain name etc).
ValidationUtils only contains very basic checks and I know I can write a regular expression in the validate() method however prefer to avoid it inm case someone has already done it :)
Thanks
In the past, I have always utilized Hibernate Validator. Simply annotate the appropriate field in your form bean with a #URL constraint.
If you've never used the ORM part of Hibernate before, don't let that scare you. The Validator portion is not dependent on the ORM stuff, and integrating it into Spring is very straightforward.
If for some reason you can't use Hibernate Validator... or you just want to stick with what you're comfortable with, a good place for regex's is RegExLib.com; several patterns that can match a URI are listed there.
Ended up using UrlValidator from apache commons.
I know this question is quite old, but I just need the same and I think I'll go with the PropertyEditors in SpringFramework.
More precisely there is URLEditor, which you can use to convert a String representation to an actual URL object.
Here is a link to the respective documentation:
http://docs.spring.io/spring/docs/current/spring-framework-reference/htmlsingle/#beans-beans-conversion
http://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/beans/propertyeditors/URLEditor.html
In my case, I think about using the following code within a Spring Validator to check whether a String entered by a user is a valid URL or not:
try {
PropertyEditor urlEditor = new URLEditor();
urlEditor.setAsText(field.getValue());
} catch (IllegalArgumentException ex) {
errors.rejectValue("nameOfTheFieldToBeValidated", "url_is_invalid");
}
However, as for now, I'm unsure whether it is possible to configure which protocol is going to be accepted as valid (i.e. URLEditor seems to also accept URLs starting with "classpath:")
Use a spring interceptor:
http://java.dzone.com/articles/using-spring-interceptors-your