I am using Viewable in my REST environment to display JSPs. But when I am passing parameters through Viewable, I am not able access this parameter in JSP.
I have following code in my java file -
Map<String, Object> map = new HashMap<String, Object>();
map.put("posts", posts);
map.put("name", "satpute");
return new Viewable("/home",map);
I used different options to access this map parameter in JSP, but this returns null. I have used following ways -
<% String name = (String)request.getAttribute("name"); out.print(name); %>
Returns NULL.
Other way I tried to use it is -
<% String name = (String) pageContext.getAttribute("name"); out.print(name); %>
Returns NULL.
Sorry if this is a very basic question, but I have used request in JSP with servlet. But I am not able to figure out how to use JSP with Viewable.
Please help.
You have to receive the map parameter instead of name,
<% Map<String, Object> map= Map<String, Object>request.getAttribute("map");
for (Map.Entry<String, Object> entry : map.entrySet()) {
String key = entry.getKey();
Object value = entry.getValue();
}%>
I'm not sure about your posts object (What kind of object). from value you can get the object, then cast it and iterate again to get the values.
But I would suggest to go with JSTL hereafter.
Related
I was instructed to create webservices ( with Spring-Boot ). My colleague gave me the url of the webservice and it looks like this : http://172.20.40.4:8080/Oxalys_WS/stock/ITM=1559
In general we create a RestController with the url :
#RestController
#RequestMapping("stock")
public class StockController {
#Autowired
private StockService stockService;
#GetMapping(value = "/{code}", produces = "application/json")
public JsonModel getByCode(#PathVariable String code) {
JsonModel jsonModel = new JsonModel();
final Map<String, Object> data = new HashMap<>();
List<Stock> stock = stockService.getByCode(code);
data.put("stock", stock);
data.put("stockTotal", stockService.getTotal(code));
jsonModel.setDatas(data);
return jsonModel;
}
}
So is it normal to create a Restful Spring-Boot webservice with a parameter in the url ?
Spring provides parameter in two standard way.
Query Param : http://172.20.40.4:8080/Oxalys_WS/stock?ITM=1559
Path Variable : http://172.20.40.4:8080/Oxalys_WS/stock/1559
Query Param :- It is a typical old way to pass some value as QueryParam with using of some variable starts with ?(Question Mark) and value is assigned using =(equals).
PathVariable :- this is a newer pattern introduce for REST-api Services. URL must be structured such in a way that this should not look too messy if multiple parameters need to pass within a URL.
For more info Navigate this link
Yes, you can have the one in your URL
When you are required to have the path variable, you can give in the Request URL
I'm developing a JSF page that contains a form with a lot of input string values. I don't want to create a corresponding field in the bean for each input . Is it possible to use a map instead.
Here's what i want my form input element to look like:
<h:inputText value='#{myBean.data["key"]}' /> // or something like this
And the bean contains the map as follows:
class myBean {
Map data;
...
}
What should getter and setter for map operation look like if I create such a code?
Nothing special. Just a standard getter as you should always use for model properties.
public Map<String, Object> getData() {
return data;
}
A setter is not mandatory as it won't be used anyway. EL will use map's own put() method for that. You only need to make sure that the map is already precreated in bean's (post)constructor, JSF/EL won't do that for you.
public MyBean() {
data = new HashMap<String, Object>();
}
I've got a class Module with a OneToMany binding with a class Sequence.
My aim is to show the list of Modules, and by clicking on one of them, display the associated list of Sequences
But it doesn't work, I have a HTTP 500 error.
Here there is my controller :
#RequestMapping(value="formation", method = RequestMethod.GET)
public ModelAndView allModules() {
List<Module> allModules = moduleService.findAll();
return new ModelAndView("formation", "modules", allModules);
}
#RequestMapping(value="sequences/{module}", method = RequestMethod.GET)
public String displaySequences(#PathVariable ("module") Module module, Model model) {
List<Sequence> allSequences = sequenceService.findByModule(module);
model.addAttribute("sequences", allSequences);
return "sequences";
}
and the jsp which show the list of modules to return the list of sequences
<c:forEach items="${modules}" var="module">
<ul>
<li>${module.titre}
<br/>
</li>
</ul>
</c:forEach>
So, where does my error come from?
It works when I do that:
#RequestMapping(value="/sequences/{moduleId}", method = RequestMethod.GET)
public String displaySequences(#PathVariable ("moduleId") Long moduleId, Model model) {
Module module = moduleService.findById(moduleId);
model.addAttribute("module", module);
return "sequences";
}
and I change the link with :
<a href="sequences/${module}">${module.titre}
but I'd like to understand my error.
The reason why you weren't able to display sequences is Spring doesn't know how to parse this
/cmap-web/sequences/com.almerys.jpa.tomcatspring.Module#12b0f0ae
into Module instance.
You can read on this in Spring docs here in the section's 16.3.2.2 URI Template Patterns last paragraph. I paste it here for convenience.
A #PathVariable argument can be of any simple type such as int, long, Date, etc. Spring automatically converts to the appropriate type or throws a TypeMismatchException if it fails to do so. You can also register support for parsing additional data types. See Section 16.3.3.14, “Method Parameters And Type Conversion” and Section 16.3.3.15, “Customizing WebDataBinder initialization”.
How do I define my own feedback messages in Wicket?
For example: if I give an incorrect username, I want to get an error message like "The user name in incorrect, try to login again." instead of using the default error message.
What would an example be like?
You can display your own error messages using error() and warn() and info(). If you want to show errors dependent on validators or the required flag you can define a properties file with the same name as the class which contains a mapping of field -> message. For example:
Index.java
Form form = new Form("myform");
form.add(new TextField("name").setRequired(true));
form.add(new PasswordTextField("password").setRequired(true));
form.add(new TextField("phonenumber").setRequired(true));
Index.properties
Required=Provide a ${label} or else...
All required fields
myform.name.Required=You have to provide a name
The field name in the form myform when it is required.
password.Required=You have to provide a password
Any field with the name password when it is required.
phonenumber.Required=A telephone number is obligatory.
Any field with the name phonenumber when it is required.
This shows a variety of ways of setting a feedback message for specific components.
You can also put the properties files next to the following component level (in order of importance, top highest):
Page Class
Component Class
Your Application Class
Wickets Application Class
Hope that helps
#user1090145: I've used overloaded Component's error() method in Validator's class:
private void error(IValidatable<String> validatable, String errorKey) {
ValidationError error = new ValidationError();
error.addMessageKey(errorKey);
validatable.error(error);
}
and invoked it in validate() by
error(validatable, "your-form.field.text-id");
Properties your-form.field.text-id must be defined in YourPage.properties
Sources:
Create custom validator in Wicket and
Form validation messages
you should set Feed back message to Session
message = "message";
Session.get().getFeedbackMessages().success(null, message);
You can use an anonymous IValidationError class and the messageSource.getMessage method to get a custom message from your property file:
error(new IValidationError() {
#Override
public Serializable getErrorMessage(IErrorMessageSource messageSource) {
//create a list of the arguments that you will use in your message string
Map<String, Object> vars = new HashMap<String, Object>();
vars.put("invalidUsername", getInvalidUsernameInput());
//get the message string from the property file
return messageSource.getMessage("mysettings.invalid_username", vars);
}
});
Sample property file:
mysettings.invalid_username=The user name "${invalidUsername}" is incorrect.
In my MVC2 AdminArea I'd like to create an overview table for each of my domain models.
I am using DataAnnotations like the following for the properties of those domain model objects:
[DisplayName("MyPropertyName")]
public string Name { get; set; }
Now my question is: How can I access the DisplayName Attribute if my view receives a collection of my domain models? I need this to build the table headers which are defined outside of the usual
<% foreach (var item in Model) { %>
loop. Inside this loop I can write
<%: Html.LabelFor(c => item.Name) %>
but is there any way to access this information using the collection of items instead of a concrete instance?
Thanks in advance!
There is a ModelMetaData class that has a static method called FromLambdaExpression. If you call it and pass in your property, along with your ViewData, it will return an instance of ModelMetaData. That class has a DisplayName property that should give you what you need. You can also get other meta data information from this object.
For example, you can create an empty ViewDataDictionary object to get this information. It can be empty because the ModelMetaData doesn't actually use the instance, it just needs the generic class to define the type being used.
//This would typically be just your view model data.
ViewDataDictionary<IEnumerable<Person>> data = new ViewDataDictionary<IEnumerable<Person>>();
ModelMetadata result = ModelMetadata.FromLambdaExpression(p => p.First().Name, data);
string displayName = result.DisplayName;
The First() method call doesn't break even if you have no actual Person object because the lambda is simply trying to find the property you want the meta data about. Similarly, you could d this for a single Person object:
//This would typically be just your view model data.
ViewDataDictionary<Person> data = new ViewDataDictionary<Person>();
ModelMetadata result = ModelMetadata.FromLambdaExpression(p => p.Name, data);
You could clean this up significantly with a helper or extension method, but this should put you on the right path.
Alright, I followed sgriffinusa's advise (thanks again!) and created a strongly typed HtmlHelper:
public static MvcHtmlString MetaDisplayName<TModel, TProperty>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression) where TModel : class
{
ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, helper.ViewData);
return MvcHtmlString.Create(metadata.GetDisplayName());
}
Of course TModel still is a collection of domain models like stated in my inital question but we can call the helper in the view like this:
<%: Html.MetaDisplayName(p => p.First().Name) %>