I am doing teplate which i will use in Smooks conversion. I need to get f.e. 2nd element of the list in freemarker but i have no idea how to do it. There is fragment of my code in freemarker template.
<#list partnerList as PARTNER>
${PARTNER.partnrid}
${PARTNER.name}
</#list>
and there is java class:
public class Partner {
private String PARTNRID;
private String NAME;
public String getPartnrid() {
return PARTNRID;
}
public void setPARTNRID(String PARTNRID) {
this.PARTNRID = PARTNRID;
}
public String getName() {
return NAME;
}
public void setNAME(String NAME) {
this.NAME = NAME;
}
}
As i said before i need ONLY 2nd element. I want to avoid printing the rest items.
Thanks!
You can get the second element of the list like this:
${partnerList[1].name}
See the freemarker documentation here.
You can also obtain the name by writing as shown below
<#list partnerList as PARTNER>
<#if PARTNER.partnrid??>
<partnrid>${PARTNER.partnrid}</partnrid>
</#if>
<name>${PARTNER.name}</name>
</#list>
Related
In our web app create and update forms have a size validation. For instance:
#Size(min = 4, max = 20)
private String mobile;
As seen the field is not required. But at the front-end user wants to clear field. Then form validation fails because of length restriction. Incoming data is an empty string instead of null. So minimum length validation restricts the input.
Therefore I start to search a solution to convert empty strings to null values. I found a #InitBinder and StringTrimmerEditor solution but our system uses #ResponseBody approach. So It doesn't fit.
Adding #JsonDeserialize(using = CustomTrimDeserializer.class) annotation or writing a custom setter for every string field is not DRY solution.
I just want to add app wide custom deserializer for String fields.
I finally examine the JsonComponentModule class and noticed spring is looking for the JsonComponent annotation for deserializer registration.
This is a one file spring boot project for solution
#RestController
#SpringBootApplication
public class CheckNullApplication {
public static void main(String[] args) {
SpringApplication.run(CheckNullApplication.class, args);
}
#PostMapping("/check-null")
public boolean checkNull(#RequestBody final HelloForm form) {
return form.getName() == null;
}
public static class HelloForm {
private String name;
public String getName() { return name; }
public void setName(final String name) { this.name = name;}
}
#JsonComponent
public static class StringTrimmerDeserializer extends JsonDeserializer<String> {
#Override
public String deserialize(final JsonParser p, final DeserializationContext ctxt)
throws IOException, JsonProcessingException {
String result = StringDeserializer.instance.deserialize(p, ctxt);
if (result != null) {
result = result.trim();
if (StringUtils.isEmpty(result)) {
return null;
}
}
return result;
}
}
}
Instead of adding #JsonDeserialize annotation you may want to just register your custom deserializer via Module (for example, SimpleModule), and it will apply to all String valued properties. Something like:
SimpleModule module = new SimpleModule(...);
module.addDeserializer(String.class, new CustomTrimDeserializer());
mapper.registerModule(module);
Create a class as following and annotate with #JsonComponent. Spring boot will pick that up as a component.
import com.fasterxml.jackson.databind.deser.std.StringDeserializer;
#JsonComponent
public class WhitSpaceTrimmerDeserializer extends StringDeserializer {
#Override
public String deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
final String value = super.deserialize(p, ctxt);
return value!=null?value.trim():null;
}
I found below answered question
Different names of JSON property during serialization and deserialization
Unfortunately this does not work when we use Spring Restful webservice. I am not sure what is cauisng the issue but it gives some Field abiguity exception.
What I want to do is Serialize and deserialize a field name with different names.
For e.g.
class Test {
private String name;
#JsonProperty("myName")
public String getName() {
return name;
}
#JsonProperty("yourName")
public void setName(String name) {
this.name = name;
}
}
This does not work in Spring rest
You can not set #JsonProperty for both (getter & setter). You can set for the field or setter method.
But you want different name for request and response, Create two classes like this.
class StudentResponse{
#JsonProperty(name="student_name)
private String name;
//getter & setter
}
class StudentRequest{
#JsonProperty(name="name)
private String name;
//getter & setter
}
Damith is right, you seem to not be able to mark both methods within the same class, however there is a way to solve this:
First off, you will have to Create a custom deserializer (or serializer, depends on your preference).
My example object:
#JsonDeserialize(using = ObjectDeserializer.class)
public class MyObject {
private String name;
public void setName(String name) {
this.name = name;
}
#JsonProperty("SomeOtherName")
public String getName() {
return name;
}
}
Note, i mark the getter as the property with the first name. And I give the class a custom deserializer. Which looks like that:
public class ObjectDeserializer extends JsonDeserializer<MyObject> {
#Override
public MyObject deserialize(JsonParser jp, DeserializationContext ctxt)
throws IOException, JsonProcessingException {
MyObject object = new MyObject();
JsonNode node = jp.getCodec().readTree(jp);
JsonNode jsonNode = node.get("MyCustomSerializeName");
object.setName(jsonNode.getTextValue());
return object;
}
}
This class will create my custom object and get the name of the setter field description (rather than relying on the property name).
Put together, i get:
public class DeserializeTest {
public static void main(String[] args) throws JsonGenerationException, JsonMappingException, IOException {
ObjectMapper mapper = new ObjectMapper();
MyObject o = new MyObject();
o.setName("Hello");
String writeValueAsString = mapper.writeValueAsString(o);
System.out.println(writeValueAsString);
String jsonObj = "{\"MyCustomSerializeName\":\"Other Test\"}";
MyObject readValue = mapper.readValue(jsonObj, MyObject.class);
System.out.println(readValue.getName());
}
}
And this outputs:
{"SomeOtherName":"Hello"}
Other Test
I hope that helps you.
We are using JPA Entities to get the database rows and then when we transfer that to the external, we want to use disconnected object (DTO) which are simple beans annotated with JAX-B.
We use a mapper and its code looks like this:
public BillDTO map(BillEntity source, BillDTO target) {
BeanUtils.copyProperties(source, target);
return target;
}
But when the code is running we get an error like this:
java.lang.IllegalArgumentException: argument type mismatch
Note this is the Spring implementation of the BeanUtils:
import org.springframework.beans.BeanUtils
And the naming of the properties are identical (with their getter/setter).
Anybody knows why the error happens?
And how to use a fast way instead just copying properties one by one?
This example working well. Here String property is copied to enum property:
Entity:
public class A {
private String valueFrom;
public String getValue() {
return valueFrom;
}
public void setValue(String value) {
this.valueFrom = value;
}
}
DTO (En is enumeration):
public class B {
private En valueTo;
public void setValue(String def) {
this.valueTo = En.valueOf(def);
}
public void setEnumValue(En enumVal) {
this.valueTo = enumVal;
}
}
As for your GitHub example, problem in class B in getter should be:
public String getValue()
Example:
public String getValue() {
return value.toString();
}
I know how to return on XML element from my controller.
What if I need to return a List of a specific class? What I can think of is a wrapper object holding a List. Is there another way to do this?
#RequestMapping(value = "/test", method = RequestMethod.GET, produces = "application/xml")
public #ResponseBody
Test getTest() {
return new Test();
}
#XmlRootElement
public class Test {
private String name = "kalle";
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
I haven't tried this but you can create custom message converter that converts list into xml vice versa and then inject it to the message converters of the application context.
Attention advanced Freemarker gurus:
I want to use a single freemarker template to be able to output tables of arbitrary pojos, with the columns to display defined separately than the data. The problem is that I can't figure out how to get a handle to a function on a pojo at runtime, and then have freemarker invoke that function (lambda style). From skimming the docs it seems that Freemarker supports functional programming, but I can't seem to forumulate the proper incantation.
I whipped up a simplistic concrete example. Let's say I have two lists: a list of people with a firstName and lastName, and a list of cars with a make and model. would like to output these two tables:
<table>
<tr>
<th>firstName</th>
<th>lastName</th>
</tr>
<tr>
<td>Joe</td>
<td>Blow</d>
</tr>
<tr>
<td>Mary</td>
<td>Jane</d>
</tr>
</table>
and
<table>
<tr>
<th>make</th>
<th>model</th>
</tr>
<tr>
<td>Toyota</td>
<td>Tundra</d>
</tr>
<tr>
<td>Honda</td>
<td>Odyssey</d>
</tr>
</table>
But I want to use the same template, since this is part of a framework that has to deal with dozens of different pojo types.
Given the following code:
public class FreemarkerTest {
public static class Table {
private final List<Column> columns = new ArrayList<Column>();
public Table(Column[] columns) {
this.columns.addAll(Arrays.asList(columns));
}
public List<Column> getColumns() {
return columns;
}
}
public static class Column {
private final String name;
public Column(String name) {
this.name = name;
}
public String getName() {
return name;
}
}
public static class Person {
private final String firstName;
private final String lastName;
public Person(String firstName, String lastName) {
this.firstName = firstName;
this.lastName = lastName;
}
public String getFirstName() {
return firstName;
}
public String getLastName() {
return lastName;
}
}
public static class Car {
String make;
String model;
public Car(String make, String model) {
this.make = make;
this.model = model;
}
public String getMake() {
return make;
}
public String getModel() {
return model;
}
}
public static void main(String[] args) throws Exception {
final Table personTableDefinition = new Table(new Column[] { new Column("firstName"), new Column("lastName") });
final List<Person> people = Arrays.asList(new Person[] { new Person("Joe", "Blow"), new Person("Mary", "Jane") });
final Table carTable = new Table(new Column[] { new Column("make"), new Column("model") });
final List<Car> cars = Arrays.asList(new Car[] { new Car("Toyota", "Tundra"), new Car("Honda", "Odyssey") });
final Configuration cfg = new Configuration();
cfg.setClassForTemplateLoading(FreemarkerTest.class, "");
cfg.setObjectWrapper(new DefaultObjectWrapper());
final Template template = cfg.getTemplate("test.ftl");
process(template, personTableDefinition, people);
process(template, carTable, cars);
}
private static void process(Template template, Table tableDefinition, List<? extends Object> data) throws Exception {
final Map<String, Object> dataMap = new HashMap<String, Object>();
dataMap.put("tableDefinition", tableDefinition);
dataMap.put("data", data);
final Writer out = new OutputStreamWriter(System.out);
template.process(dataMap, out);
out.flush();
}
}
All the above is a given for this problem. So here is the template I have been hacking on. Note the comment where I am having trouble.
<table>
<tr>
<#list tableDefinition.columns as col>
<th>${col.name}</th>
</#list>
</tr>
<#list data as pojo>
<tr>
<#list tableDefinition.columns as col>
<td><#-- what goes here? --></td>
</#list>
</tr>
</#list>
</table>
So col.name has the name of the property I want to access from the pojo. I have tried a few things, such as
pojo.col.name
and
<#assign property = col.name/>
${pojo.property}
but of course these don't work, I just included them to help convey my intent. I am looking for a way to get a handle to a function and have freemarker invoke it, or perhaps some kind of "evaluate" feature that can take an arbitrary expression as a string and evaluate it at runtime.
?eval is (almost?) always a bad idea, because it often comes with performance drawbacks (e.g. a lot of parsing) and security problems (e.g. "FTL injection").
A better approach is using the square bracket syntax:
There is an alternative syntax if we want to specify the subvariable name with an expression: book["title"]. In the square brackets you can give any expression as long as it evaluates to a string.
(From the FreeMarker documentation about retrieving data from a hash)
In your case I'd recommend something like ${pojo[col.name]}.
Found the answer.
${("pojo." + col.name)?eval}