I'm just wondering if it's possible to tell an #InitBinder that empty float values in a form would be converted to 0.
I know that float is a primitive data type but I'd still like to convert null or empty values to 0.
If that is possible, how can i achieve that?
Otherwise I'll just make a workaround using a String instead of a float
Define a subclsss of CustomNumberEditor as
import org.springframework.beans.propertyeditors.CustomNumberEditor;
import org.springframework.util.StringUtils;
public class MyCustomNumberEditor extends CustomNumberEditor {
public MyCustomNumberEditor(Class<? extends Number> numberClass) throws IllegalArgumentException {
super(numberClass, true);
}
#Override
public void setAsText(String text) throws IllegalArgumentException {
if (!StringUtils.hasText(text)) {
setValue(0);
}else {
super.setAsText(text.trim());
}
}
}
Then in your controller class (I create a BaseController for all my application controllers, I need this behavior for all the numeric primitive types in my application, so I simply define this in my BaseController), register binders for the various primitive types.
Note that the constructor parameter of MyCustomNumberEditor must be a subclass of Number, instead of primitive class type.
#InitBinder
public void registerCustomerBinder(WebDataBinder binder) {
binder.registerCustomEditor(double.class, new MyCustomNumberEditor(Double.class));
binder.registerCustomEditor(float.class, new MyCustomNumberEditor(Float.class));
binder.registerCustomEditor(long.class, new MyCustomNumberEditor(Long.class));
binder.registerCustomEditor(int.class, new MyCustomNumberEditor(Integer.class));
....
}
Yes you could always do that .Spring have a CustomNumberEditor which is a customizable property editor for any Number subclass like Integer, Long, Float, Double.It is registered by default by BeanWrapperImpl,but, can be overridden by registering custom instance of it as custom editor.It means you could extend a class like this
public class MyCustomNumberEditor extends CustomNumberEditor{
public MyCustomNumberEditor(Class<? extends Number> numberClass, NumberFormat numberFormat, boolean allowEmpty) throws IllegalArgumentException {
super(numberClass, numberFormat, allowEmpty);
}
public MyCustomNumberEditor(Class<? extends Number> numberClass, boolean allowEmpty) throws IllegalArgumentException {
super(numberClass, allowEmpty);
}
#Override
public String getAsText() {
//return super.getAsText();
return "Your desired text";
}
#Override
public void setAsText(String text) throws IllegalArgumentException {
super.setAsText("set your desired text");
}
}
And then register it normally in you controller:
#InitBinder
public void initBinder(WebDataBinder binder) {
binder.registerCustomEditor(Float.class,new MyCustomNumberEditor(Float.class, true));
}
This should do the task.
Related
I've got a simple REST resource which accepts a couple of query parameters. I'd like to validate one of these parameters, and came across ConstraintValidator for this purpose. The REST resource expects the query param territoryId to be a UUID, so I'd like to validate that it indeed is a valid UUID.
I've created an #IsValidUUID annotation, and a corresponding IsValidUUIDValidator (which is a ConstraintValidator). With what I have now, nothing gets validated and getSuggestions accepts anything I throw at it. So clearly I'm doing something wrong.
What am I doing wrong?
The REST resource now looks like this :
#Component
#Path("/search")
public class SearchResource extends AbstractResource {
#GET
#Path("/suggestions")
#Produces(MediaType.APPLICATION_XML)
public Response getSuggestions(
#QueryParam("phrase") List<String> phrases,
#IsValidUUID #QueryParam("territoryId") String territoryId) {
[...]
}
}
IsValidUUID
#Target({ElementType.TYPE, ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER})
#Retention(RetentionPolicy.RUNTIME)
#Documented
#Constraint(validatedBy = {IsValidUUIDValidator.class})
public #interface IsValidUUID {
String message() default "Invalid UUID";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
IsValidUUIDValidator
public class IsValidUUIDValidator implements ConstraintValidator<IsValidUUID, String> {
#Override
public void initialize(IsValidUUID constraintAnnotation) {
}
#Override
public boolean isValid(String value, ConstraintValidatorContext context) {
if (value == null) {
return true;
}
try {
UUID.fromString(value);
return true;
} catch (Exception e) {
context.disableDefaultConstraintViolation();
context.buildConstraintViolationWithTemplate("The provided UUID is not valid")
.addConstraintViolation();
return false;
}
}
}
You need to set the supported targets on IsValidUUID, using the following annotation.
#SupportedValidationTarget(ValidationTarget.ANNOTATED_ELEMENT)
or
#SupportedValidationTarget(ValidationTarget.PARAMETERS)
Edit:
Sorry, I wasn't able to make it work either on a RequestParam directly. However, if you can, try creating a POJO that you can bind your request parameters to and annotate the binding field with your constraint instead. This worked for me.
public class MyModel {
#IsValidUUID
private String territoryId;
public String getTerritoryId() {
return territoryId;
}
public void setTerritoryId(String territoryId) {
this.territoryId = territoryId;
}
}
#GET
#Path("/suggestions")
#Produces(MediaType.APPLICATION_XML)
public Response getSuggestions(
#QueryParam("phrase") List<String> phrases,
#Valid #ModelAttribute MyModel myModel) {
[...]
}
I have a list of strings which should be of a specific format. I need to return the error message with the strings which are not of the format specified. How to do this with spring validation(I am using the hibernate validator).
The annotation:
#Documented
#Retention(RUNTIME)
#Target({FIELD, METHOD})
#Constraint(validatedBy = HostsValidator.class)
public #interface HostsConstraint {
String message();
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
The implementation:
public class HostsValidator implements ConstraintValidator<HostsConstraint, List<String>>{
#Override
public void initialize(OriginHostsConstraint constraintAnnotation) {
}
#Override
public boolean isValid(List<String> strings, ConstraintValidatorContext context) {
for (String s : strings) {
if (!s.matches("[0-9]+") {
//How do I say: Invalid string <s> ?
return false;
}
}
}
}
The usage:
public class Test {
#HostsConstraint(message="Invalid string ")
private List<String> hosts;
}
Using validatedValue will give the entire list.
Use JSR 380 validation, it allows container element constraints.
Here is a link to the container element section in the Hibernate Validator 6.0.6.FINAL Document
I think I found a solution but it is coupled to hibernate validator. May be it is even a hacky implementation.
The usage:
public class Test {
#HostsConstraint(message="Invalid string : ${invalidStr}")
private List<String> hosts;
}
The implementation
public class HostsValidator implements ConstraintValidator<HostsConstraint, List<String>>{
#Override
public void initialize(OriginHostsConstraint constraintAnnotation) {}
#Override
public boolean isValid(List<String> strings, ConstraintValidatorContext context) {
for (String s : strings) {
if (!s.matches("[0-9]+") {
ConstraintValidatorContextImpl contextImpl =
(ConstraintValidatorContextImpl) context
.unwrap(HibernateConstraintValidatorContext.class);
contextImpl.addExpressionVariable("invalidStr", s);
return false;
}
}
}
}
In a form I take a comma separated list of integers and convert them to an ArrayList<Integer>. This works fine. My form-backing object is:
public class FormDto {
#NotNull
private ArrayList<Integer> nList;
// getters and setters
}
In the form I have:
<input type="text" class="form-control" id="nList" th:field="*{nList}" required="required"/>
Apparently spring automatically converts the string into an ArrayList. Just in case I also created a Converter:
public class CSVStringToListConverter implements Converter<String, ArrayList<Integer>>{
#Override
public ArrayList<Integer> convert(String arg0) {
ArrayList<Integer> list = new ArrayList<Integer>();
for (String s : arg0.split(",")) {
list.add(Integer.parseInt(s));
}
return list;
}
}
which I add in
#Configuration
#EnableWebMvc
public class MvcConfig extends WebMvcConfigurerAdapter implements ApplicationContextAware {
#Override
public void addFormatters(FormatterRegistry registry) {
registry.addConverter(new CSVStringToListConverter());
}
}
Is this all I have to do in order to make converters work? As I wrote, the conversion also works without this converter, so I am unsure whether my converter is actually used or whether it still uses the built-in converter.
My main question however is how to validate the input String (not the ArrayList)? For form fields without conversion I just do that in the controller with:
#PostMapping("/submitForm")
public String formSubmit(#ModelAttribute #Valid SortingExplicitDto sortingExplicitDto, BindingResult result, Model model) {
if(result.hasErrors()) {
model.addAttribute("formDto", new formDto());
return "submitForm";
}
}
Is it possible to validate the input String in the same way, or do I have to do that with Javascript or in the converter?
addition
After a few more tests, I noticed that it does use my custom converter, which does answer my first question. Still I am wondering how to deal with the validation. If I enter some random string which are not integers separated by comma, I receive an exception:
Failed to convert property value of type [java.lang.String] to required type [java.util.ArrayList] for property nList; nested exception is org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.String] to type [#javax.validation.constraints.NotNull java.util.ArrayList<java.lang.Integer>] for value ,2,3; nested exception is java.lang.NumberFormatException: For input string:
Also I can do all my validation inside the CSVStringToListConverter and throw an exception if validation fails. I believe I should then catch the exception in the controller and somehow display a nice human readable message in the form. In the html, I display errors (including the one above) with:
<span id="errornList" class="alert alert-danger" th:if="${#fields.hasErrors('nList')}" th:errors="*{nList}">NList error</span>
How do I catch the exception in the controller and put a nice error message there?
Your converter can be this way:
#Component
public class CSVStringToListConverter implements Converter<String, List<Integer>> {
#Autowired
private Errors errors;
#Override
public List<Integer> convert(String arg0) {
List<Integer> list = new ArrayList<Integer>();
for (String s : arg0.split(",")) {
try {
list.add(Integer.parseInt(s));
} catch (NumberFormatException e) {
list = Collections.emptyList();
errors.rejectValue("fieldName", "fieldName.invalid", "Invalid integer in list");
}
}
return list;
}}
Register the Converter in a Configuration class
#Configuration
public class WebConfig implements WebMvcConfigurer {
#Override
public void addFormatters(FormatterRegistry registry) {
registry.addConverter(new CSVStringToListConverter());
}
}
I only Injected the "Errors" class in order to display "nice human readable message in the form" as you wish to have.
Use "org.springframework.validation.BindException" implementation of Errors class, since Errors is an interface, preferably in a configuration class and then the injection should work.
I get Exception
org.springframework.beans.NotReadablePropertyException: Invalid property 'entries[0].reason' of bean class [my.company.data.SDROrder]: Bean property 'entries[0].reason' is not readable or has an invalid getter method: Does the return type of the getter match the parameter type of the setter?
from the following code snippet:
Errors errors = new BeanPropertyBindingResult(new SDROrder(), "sdr");
orderValidator.validate(order, errors);
for validator:
public class OrderValidator implements Validator
{
#Override
public boolean supports(Class<?> clazz)
{
return Order.class.isAssignableFrom(clazz);
}
#Override
public void validate(final Object target, final Errors errors)
{
errors.rejectValue("entries[0].reason", "Wrong Reason");
}
}
where we have such data hierarchy
public class Order
{
private List<AbstractOrderEntry> entries;
public List<AbstractOrderEntry> getEntries()
{
return entries;
}
public void setEntries(List<AbstractOrderEntry> entries)
{
this.entries = entries;
}
}
public class SDROrder extends Order
{
}
public class AbstractOrderEntry
{
}
public class SDROrderEntry extends AbstractOrderEntry
{
private String reason;
public String getReason()
{
return reason;
}
public void setReason(String reason)
{
this.reason = reason;
}
}
Please see working example here: here
Update 1: Just to clarify. The problem is I try to rejectValue on object that has Collection of objects where each element has specific attribute at Runtime but has not it at Compile time. Spring uses Bean's properties to resolve these fields and can't find inherited attribute. The question is: can I explain Spring to resolve inherited fields somehow?
I found the solution here.
The trick is at
org.springframework.validation.Errors.pushNestedPath(String)
and
org.springframework.validation.Errors.popNestedPath()
methods.
The correct validation should be done as follow:
errors.pushNestedPath("entries[0]");
errors.rejectValue("reason", "Wrong Reason");
errors.popNestedPath();
Here is my ConfigUpdater class
private final class ConfigUpdater implements ManagedService {
#SuppressWarnings("rawtypes")
#Override
public void updated(Dictionary config) throws ConfigurationException {
if (config == null) {
return;
}
String title = ((String)config.get("title"));
}
}
My question is how can I access String title in any other class? Or how can I get config dictionary in any other class... Method updated will only be called when a config file is changed... once it is changed how can access its data in other class?
In general you would create a service that exposes these properties to other components.
For example, you could give your ConfigUpdater a second interface. Another component can than lookup/inject this interface from the service registry and use it's methods to access the properties.
I created an example project on GitHub: https://github.com/paulbakker/configuration-example
The most important part is the service that implements both ManagedService and a custom interface:
#Component(properties=#Property(name=Constants.SERVICE_PID, value="example.configurationservice"))
public class ConfigurationUpdater implements ManagedService, MyConfiguration{
private volatile String message;
#Override
public void updated(#SuppressWarnings("rawtypes") Dictionary properties) throws ConfigurationException {
message = (String)properties.get("message");
}
#Override
public String getMessage() {
return message;
}
}
The configuration can then be used like this:
#Component(provides=ExampleConsumer.class,
properties= {
#Property(name = CommandProcessor.COMMAND_SCOPE, value = "example"),
#Property(name = CommandProcessor.COMMAND_FUNCTION, values = {"showMessage"}) })
public class ExampleConsumer {
#ServiceDependency
private volatile MyConfiguration config;
public void showMessage() {
String message = config.getMessage();
System.out.println(message);
}
}