I am building a Blazor (Server) EditForm which contains an InputTextArea. By default, it looks like the InputTextArea creates a textArea with 2 rows, but I would prefer 4 rows for this specific application.
How do you set the number of rows for a Blazor InputTextArea?
You can simply add the rows attribute like below.
<InputTextArea #bind-Value="#prop" rows="4"></InputTextArea>
It does not require any C# as this is just html.
I would love to know if there is another way, but after searching for a while, I was able to find this solutions.
In your C# code, create a property of type Dictionary<string, object>.
Dictionary<string, object> inputTextAreaAttributes = new Dictionary<string, object>();
Override OnInitializedAsync and add a new item to your dictionary.
Dictionary<string, object> inputTextAreaAttributes = new Dictionary<string, object>();
protected override Task OnInitializedAsync()
{
inputTextAreaAttributes.Add("rows", "4");
}
Set the #Attribute property of the InputTextArea to your dictionary.
<InputTextArea #bind-Value="#prop" #attributes="inputTextAreaAttributes"></InputTextArea>
Related
I am creating a web aplication using Angular 8 for the frontend, and Spring Boot for the backend (I am quite new to SpringBoot programming)
I have a table with a list of "protocols" and a checkbox filter above it. Here is a screenshot of the webpage:
When I click "Apply Filters" button, it generates a JSON array like this:
[{subject_id:[2,3]},{scenario_id:[2]},{algorithms_id:[2]}]
Now, in the backend, I want to create a filter using this JSON array, so that it returns only the corresponding protocols. I guess I have to use a Query functionality and #GetMapping in java SpringBoot. But I don't know how to specify which JSON item to use for each attribute of "protocol". If you could give me some advice on how to do this, I would really appreciate it.
Why not make a Java class - Filter.java with fields :
private List<String> subject_id=new ArrayList<>();
private List<String> scenario_id=new ArrayList<>();
private List<String> algorithms_id=new ArrayList<>();
and then write a POST controller with a RequestBody like:
#RequestMapping(value = "/myapi", method = RequestMethod.POST)
public ResponseEntity<String> getResultsByFilter(
#RequestBody(required = true) List<Filter> filters)
this way you can get the filter in the request body and then process it as per your business logic to return results as you want them.
I'm really stuck with cast Rabbit response to POJO. How to do it properly? On sprin.io just no practical example.
So I'm trying to do it with this
#Bean
public DefaultClassMapper typeMapper() {
DefaultClassMapper typeMapper = new DefaultClassMapper();
Map<String, Class> idClassMapping = new HashMap<String, Class>();
idClassMapping.put("range", Loan.class);
typeMapper.setIdClassMapping(idClassMapping);
//typeMapper.setDefaultType(Loan.class);
return typeMapper;
}
#Bean
public MessageConverter messageConverter(DefaultClassMapper defaultClassMapper){
JsonMessageConverter jsonMessageConverter = new JsonMessageConverter();
jsonMessageConverter.setClassMapper(defaultClassMapper);
return jsonMessageConverter;
}
"range" actually fake value from example. Also this really doesn't work type problemn on .setIdClassMapping() . Also I can't use default mapper because serve send header without type hinting field. And I have no control on this remote server. Data format always JSON.
Caused by: org.springframework.amqp.support.converter.MessageConversionException: failed to convert Message content. Could not resolve __TypeId__ in header
Any suggestions working example for marshalling/demarshalling Java objects. I have completely different class for send back value from my code. I'm using java 8.
Just write your own ClassMapper - don't use the default one if your decision criteria to choose the class type is not compatible with its internals.
Or, you can subclass the DefaultClassMapper and override getClassIdFieldName() to tell it which message property to use.
I need to pass a map back to the web application.
I'm used to encapsulating the map in a JSONObject
http://json.org/java/
But since I am using Spring and Jackson Haus.
is there an easier way to maintain the pojo? May I can just annotate the MAP ?
Jackson has com.fasterxml.jackson.core.JsonNode, and specific subtypes like ObjectNode.
These form so-called Tree Model, which is one of 3 ways to handle JSON with Jackson -- some other libraries (like org.json) only offer this way.
So you should be able to just use JsonNode instead; there is little point in using org.json library; it is slow, and has outdated API.
Alternatively you can just use java.util.Map, and return that. Jackson can handle standard Lists, Maps and other JDK types just fine.
If you need to manipulate the output, ie, you don't want to provide all the fields of the object you can use JSonArray:
#RequestMapping(value = "/api/users", method = RequestMethod.GET)
public
#ResponseBody
String listUsersJson(ModelMap model) throws JSONException {
JSONArray userArray = new JSONArray();
for (User user : userRepository.findAll()) {
JSONObject userJSON = new JSONObject();
userJSON.put("id", user.getId());
userJSON.put("firstName", user.getFirstName());
userJSON.put("lastName", user.getLastName());
userJSON.put("email", user.getEmail());
userArray.put(userJSON);
}
return userArray.toString();
}
Use the example from here
Otherwise if you add jackson to your dependencies and set the controller method anotatted with #ResponseBody the response will automatically mapped to JSON. Check here for a simple example.
I'm aware that there are multiple way to tell JacksonJson to ignore
properties during rendering but all of them are static. (JasonIgnore, MixIn classes, ..).
This is my scenario. A domain object can implement a interface called FilteredDomain to
allow it to be dynamically filtered. The interface is simple and only exposes one method
"getIgnoreProperties". (A list of properties to ignore).
I then register a Custom Serializer that binds to the FilteredDomain object. The
code looks something like:
private class FilteredDomainSerializer extends JsonSerializer<FilteredDomain> {
public void serialize(FilteredDomain arg, JsonGenerator jgen,
SerializerProvider provder) throws IOException,
JsonProcessingException {
final BeanWrapper wrapper = PropertyAccessorFactory.forBeanPropertyAccess(arg);
for (PropertyDescriptor pd : wrapper.getPropertyDescriptors()) {
final String name = pd.getName();
if (arg.getIgnoreProperties().containsKey(name))
continue;
final Object value = wrapper.getPropertyValue(name);
jgen.writeObjectField(name, value);
}
}
}
First, I really dislike that I need to use the Spring Bean wrapper to get a list of all properties and iterate through them (There must be a way to do this is jackson json).
Second, The code still dosen't work. I get the error:
org.codehaus.jackson.JsonGenerationException: Can not write a field name, expecting a value
at org.codehaus.jackson.impl.JsonGeneratorBase._reportError(JsonGeneratorBase.java:480)
at org.codehaus.jackson.impl.Utf8Generator.writeFieldName(Utf8Generator.java:270)
at org.codehaus.jackson.JsonGenerator.writeObjectField(JsonGenerator.java:1088)
at com.rootmusic.util.SystemJsonObjectMapper$ValueObjectSerializer.serialize(SystemJsonObjectMapper.java:65)
at com.rootmusic.util.SystemJsonObjectMapper$ValueObjectSerializer.serialize(SystemJsonObjectMapper.java:1)
at org.codehaus.jackson.map.ser.ContainerSerializers$IndexedListSerializer.serializeContents(ContainerSerializers.java:304)
at org.codehaus.jackson.map.ser.ContainerSerializers$IndexedListSerializer.serializeContents(ContainerSerializers.java:254)
at org.codehaus.jackson.map.ser.ContainerSerializers$AsArraySerializer.serialize(ContainerSerializers.java:142)
at org.codehaus.jackson.map.ser.MapSerializer.serializeFields(MapSerializer.java:287)
at org.codehaus.jackson.map.ser.MapSerializer.serialize(MapSerializer.java:212)
at org.codehaus.jackson.map.ser.MapSerializer.serialize(MapSerializer.java:23)
at org.codehaus.jackson.map.ser.StdSerializerProvider._serializeValue(StdSerializerProvider.java:606)
at org.codehaus.jackson.map.ser.StdSerializerProvider.serializeValue(StdSerializerProvider.java:280)
The error comes from the fact that you are not writing START_OBJECT / END_OBJECT around field-name/value pairs, so that should be easy to fix.
As to more dynamic filtering, you could read this blog entry which includes standard methods. #JsonView works if you have sets of static definitions (one of which you can dynamically select on per-serialization basis), but if you want yet more dynamic system, #JsonFilter is the way to go.
Alternatively, another relatively simple way would be to first "convert" your POJO into a Map:
Map props = objectMapper.convertValue(pojo, Map.class);
(which is similar to serializing it as JSON, except that result is a Map which would render as JSON)
and then selectively trim Map, and serialize that as JSON. Or, if you prefer, you can use JsonNode ("tree model") as the intermediate thing to modify and then serialize.
In the Play framework i have a few models that have fields which are object references to other models. When i use renderJSON, i don't want those object references to be included. Currently for my needs i create a separate view model class which contains the fields i want, and in the controller i create instances of this view class as needed. Ideally i would like to be able to use the model class itself without having to write the view class.
Is there a way to annotate a field so that it will not be serialized when using renderJSON?
because play uses Gson for its Json serialization you can try the following:
public static void test()
{
Object foo = new SomeObject("testData");
Gson gson = new GsonBuilder()
.excludeFieldsWithModifiers(Modifier.TRANSIENT)
.create();
renderJSON(gson.toJson(foo));
}
now each field marked as transient will not be serialized. There is also another (better) way. You can use the com.google.gson.annotations.Expose annotation to mark each field you want to serialize.
public static void test()
{
Object foo = new SomeObject("testData");
Gson gson = new GsonBuilder()
.excludeFieldsWithoutExposeAnnotation()
.create();
renderJSON(gson.toJson(foo));
}
Using FlexJSON with play is another option, explained in this article: http://www.lunatech-research.com/archives/2011/04/20/play-framework-better-json-serialization-flexjson
Not sure why no one has written the most direct solution to this answer so I will do it here:
Simply mark the fields you do not want serialized via Gson as transient.
Here's an example:
public class Animal
{
private String name = "dog";
transient private int port = 80;
private String species = "canine";
transient private String password = "NoOneShouldSeeThis";
}
None of the items which are marked transient will be serialized.
When deserialized they will be set to their default (class default) values.
Resulting JSON will look like the following:
{"name":"dog","species":"canine"}
For more information on transient you can see the SO
Why does Java have transient fields?
I would override renderJSON to check a the field name against a member array of serialization exclusions.