This might be a duplicate. But I cannot find a solution to my Problem.
I have a class
public class MyResponse implements Serializable {
private boolean isSuccess;
public boolean isSuccess() {
return isSuccess;
}
public void setSuccess(boolean isSuccess) {
this.isSuccess = isSuccess;
}
}
Getters and setters are generated by Eclipse.
In another class, I set the value to true, and write it as a JSON string.
System.out.println(new ObjectMapper().writeValueAsString(myResponse));
In JSON, the key is coming as {"success": true}.
I want the key as isSuccess itself. Is Jackson using the setter method while serializing? How do I make the key the field name itself?
This is a slightly late answer, but may be useful for anyone else coming to this page.
A simple solution to changing the name that Jackson will use for when serializing to JSON is to use the #JsonProperty annotation, so your example would become:
public class MyResponse implements Serializable {
private boolean isSuccess;
#JsonProperty(value="isSuccess")
public boolean isSuccess() {
return isSuccess;
}
public void setSuccess(boolean isSuccess) {
this.isSuccess = isSuccess;
}
}
This would then be serialised to JSON as {"isSuccess":true}, but has the advantage of not having to modify your getter method name.
Note that in this case you could also write the annotation as #JsonProperty("isSuccess") as it only has the single value element
I recently ran into this issue and this is what I found. Jackson will inspect any class that you pass to it for getters and setters, and use those methods for serialization and deserialization. What follows "get", "is" and "set" in those methods will be used as the key for the JSON field ("isValid" for getIsValid and setIsValid).
public class JacksonExample {
private boolean isValid = false;
public boolean getIsValid() {
return isValid;
}
public void setIsValid(boolean isValid) {
this.isValid = isValid;
}
}
Similarly "isSuccess" will become "success", unless renamed to "isIsSuccess" or "getIsSuccess"
Read more here: http://www.citrine.io/blog/2015/5/20/jackson-json-processor
Using both annotations below, forces the output JSON to include is_xxx:
#get:JsonProperty("is_something")
#param:JsonProperty("is_something")
When you are using Kotlin and data classes:
data class Dto(
#get:JsonProperty("isSuccess") val isSuccess: Boolean
)
You might need to add #param:JsonProperty("isSuccess") if you are going to deserialize JSON as well.
EDIT: If you are using swagger-annotations to generate documentation, the property will be marked as readOnly when using #get:JsonProperty. In order to solve this, you can do:
#JsonAutoDetect(isGetterVisibility = JsonAutoDetect.Visibility.NONE)
data class Dto(
#field:JsonProperty(value = "isSuccess") val isSuccess: Boolean
)
You can configure your ObjectMapper as follows:
mapper.setPropertyNamingStrategy(new PropertyNamingStrategy() {
#Override
public String nameForGetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName)
{
if(method.hasReturnType() && (method.getRawReturnType() == Boolean.class || method.getRawReturnType() == boolean.class)
&& method.getName().startsWith("is")) {
return method.getName();
}
return super.nameForGetterMethod(config, method, defaultName);
}
});
I didn't want to mess with some custom naming strategies, nor re-creating some accessors.
The less code, the happier I am.
This did the trick for us :
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonProperty;
#JsonIgnoreProperties({"success", "deleted"}) // <- Prevents serialization duplicates
public class MyResponse {
private String id;
private #JsonProperty("isSuccess") boolean isSuccess; // <- Forces field name
private #JsonProperty("isDeleted") boolean isDeleted;
}
Building upon Utkarsh's answer..
Getter names minus get/is is used as the JSON name.
public class Example{
private String radcliffe;
public getHarryPotter(){
return radcliffe;
}
}
is stored as { "harryPotter" : "whateverYouGaveHere" }
For Deserialization, Jackson checks against both the setter and the field name.
For the Json String { "word1" : "example" }, both the below are valid.
public class Example{
private String word1;
public setword2( String pqr){
this.word1 = pqr;
}
}
public class Example2{
private String word2;
public setWord1(String pqr){
this.word2 = pqr ;
}
}
A more interesting question is which order Jackson considers for deserialization. If i try to deserialize { "word1" : "myName" } with
public class Example3{
private String word1;
private String word2;
public setWord1( String parameter){
this.word2 = parameter ;
}
}
I did not test the above case, but it would be interesting to see the values of word1 & word2 ...
Note: I used drastically different names to emphasize which fields are required to be same.
You can change primitive boolean to java.lang.Boolean (+ use #JsonPropery)
#JsonProperty("isA")
private Boolean isA = false;
public Boolean getA() {
return this.isA;
}
public void setA(Boolean a) {
this.isA = a;
}
Worked excellent for me.
If you are interested in handling 3rd party classes not under your control (like #edmundpie mentioned in a comment) then you add Mixin classes to your ObjectMapper where the property/field names should match the ones from your 3rd party class:
public class MyStack32270422 {
public static void main(String[] args) {
ObjectMapper om3rdParty = new ObjectMapper();
om3rdParty .addMixIn(My3rdPartyResponse.class, MixinMyResponse.class);
// add further mixins if required
String jsonString = om3rdParty.writeValueAsString(new My3rdPartyResponse());
System.out.println(jsonString);
}
}
class MixinMyResponse {
// add all jackson annotations here you want to be used when handling My3rdPartyResponse classes
#JsonProperty("isSuccess")
private boolean isSuccess;
}
class My3rdPartyResponse{
private boolean isSuccess = true;
// getter and setter here if desired
}
Basically you add all your Jackson annotations to your Mixin classes as if you would own the class. In my opinion quite a nice solution as you don't have to mess around with checking method names starting with "is.." and so on.
there is another method for this problem.
just define a new sub-class extends PropertyNamingStrategy and pass it to ObjectMapper instance.
here is a code snippet may be help more:
mapper.setPropertyNamingStrategy(new PropertyNamingStrategy() {
#Override
public String nameForGetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName) {
String input = defaultName;
if(method.getName().startsWith("is")){
input = method.getName();
}
//copy from LowerCaseWithUnderscoresStrategy
if (input == null) return input; // garbage in, garbage out
int length = input.length();
StringBuilder result = new StringBuilder(length * 2);
int resultLength = 0;
boolean wasPrevTranslated = false;
for (int i = 0; i < length; i++)
{
char c = input.charAt(i);
if (i > 0 || c != '_') // skip first starting underscore
{
if (Character.isUpperCase(c))
{
if (!wasPrevTranslated && resultLength > 0 && result.charAt(resultLength - 1) != '_')
{
result.append('_');
resultLength++;
}
c = Character.toLowerCase(c);
wasPrevTranslated = true;
}
else
{
wasPrevTranslated = false;
}
result.append(c);
resultLength++;
}
}
return resultLength > 0 ? result.toString() : input;
}
});
The accepted answer won't work for my case.
In my case, the class is not owned by me. The problematic class comes from 3rd party dependencies, so I can't just add #JsonProperty annotation in it.
To solve it, inspired by #burak answer above, I created a custom PropertyNamingStrategy as follow:
mapper.setPropertyNamingStrategy(new PropertyNamingStrategy() {
#Override
public String nameForSetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName)
{
if (method.getParameterCount() == 1 &&
(method.getRawParameterType(0) == Boolean.class || method.getRawParameterType(0) == boolean.class) &&
method.getName().startsWith("set")) {
Class<?> containingClass = method.getDeclaringClass();
String potentialFieldName = "is" + method.getName().substring(3);
try {
containingClass.getDeclaredField(potentialFieldName);
return potentialFieldName;
} catch (NoSuchFieldException e) {
// do nothing and fall through
}
}
return super.nameForSetterMethod(config, method, defaultName);
}
#Override
public String nameForGetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName)
{
if(method.hasReturnType() && (method.getRawReturnType() == Boolean.class || method.getRawReturnType() == boolean.class)
&& method.getName().startsWith("is")) {
Class<?> containingClass = method.getDeclaringClass();
String potentialFieldName = method.getName();
try {
containingClass.getDeclaredField(potentialFieldName);
return potentialFieldName;
} catch (NoSuchFieldException e) {
// do nothing and fall through
}
}
return super.nameForGetterMethod(config, method, defaultName);
}
});
Basically what this does is, before serializing and deserializing, it checks in the target/source class which property name is present in the class, whether it is isEnabled or enabled property.
Based on that, the mapper will serialize and deserialize to the property name that is exist.
http://localhost:8080/users?firstName=a&lastName=b ---> where firstName=a and lastName=b
How to make it to or ---> where firstName=a or lastName=b
But when I set QuerydslBinderCustomizer customize
#Override
default public void customize(QuerydslBindings bindings, QUser user) {
bindings.bind(String.class).all((StringPath path, Collection<? extends String> values) -> {
BooleanBuilder predicate = new BooleanBuilder();
values.forEach( value -> predicate.or(path.containsIgnoreCase(value) );
});
}
http://localhost:8080/users?firstName=a&firstName=b&lastName=b ---> where (firstName=a or firstName = b) and lastName=b
It seem different parameters with AND. Same parameters with what I set(predicate.or/predicate.and)
How to make it different parameters with AND like this ---> where firstName=a or firstName=b or lastName=b ??
thx.
Your current request param are grouped as List firstName and String lastName. I see that you want to keep your request parameters without a binding, but in this case it would make your life easier.
My suggestion is to make a new class with request param:
public class UserRequest {
private String lastName;
private List<String> firstName;
// getters and setters
}
For QueryDSL, you can create a builder object:
public class UserPredicateBuilder{
private List<BooleanExpression> expressions = new ArrayList<>();
public UserPredicateBuilder withFirstName(List<String> firstNameList){
QUser user = QUser.user;
expressions.add(user.firstName.in(firstNameList));
return this;
}
//.. same for other fields
public BooleanExpression build(){
if(expressions.isEmpty()){
return Expressions.asBoolean(true).isTrue();
}
BooleanExpression result = expressions.get(0);
for (int i = 1; i < expressions.size(); i++) {
result = result.and(expressions.get(i));
}
return result;
}
}
And after you can just use the builder as :
public List<User> getUsers(UserRequest userRequest){
BooleanExpression expression = new UserPredicateBuilder()
.withFirstName(userRequest.getFirstName())
// other fields
.build();
return userRepository.findAll(expression).getContent();
}
This is the recommended solution.
If you really want to keep the current params without a binding (they still need some kind of validation, otherwise it can throw an Exception in query dsl binding)
you can group them by path :
Map<StringPath,List<String>> values // example firstName => a,b
and after that to create your boolean expression based on the map:
//initial value
BooleanExpression result = Expressions.asBoolean(true).isTrue();
for (Map.Entry entry: values.entrySet()) {
result = result.and(entry.getKey().in(entry.getValues());
}
return userRepository.findAll(result);
Just came across the latest build of Mono.CSharp and love the promise it offers.
Was able to get the following all worked out:
namespace XAct.Spikes.Duo
{
class Program
{
static void Main(string[] args)
{
CompilerSettings compilerSettings = new CompilerSettings();
compilerSettings.LoadDefaultReferences = true;
Report report = new Report(new Mono.CSharp.ConsoleReportPrinter());
Mono.CSharp.Evaluator e;
e= new Evaluator(compilerSettings, report);
//IMPORTANT:This has to be put before you include references to any assemblies
//our you;ll get a stream of errors:
e.Run("using System;");
//IMPORTANT:You have to reference the assemblies your code references...
//...including this one:
e.Run("using XAct.Spikes.Duo;");
//Go crazy -- although that takes time:
//foreach (Assembly assembly in AppDomain.CurrentDomain.GetAssemblies())
//{
// e.ReferenceAssembly(assembly);
//}
//More appropriate in most cases:
e.ReferenceAssembly((typeof(A).Assembly));
//Exception due to no semicolon
//e.Run("var a = 1+3");
//Doesn't set anything:
//e.Run("a = 1+3;");
//Works:
//e.ReferenceAssembly(typeof(A).Assembly);
e.Run("var a = 1+3;");
e.Run("A x = new A{Name=\"Joe\"};");
var a = e.Evaluate("a;");
var x = e.Evaluate("x;");
//Not extremely useful:
string check = e.GetVars();
//Note that you have to type it:
Console.WriteLine(((A) x).Name);
e = new Evaluator(compilerSettings, report);
var b = e.Evaluate("a;");
}
}
public class A
{
public string Name { get; set; }
}
}
And that was fun...can create a variable in the script's scope, and export the value.
There's just one last thing to figure out... how can I get a value in (eg, a domain entity that I want to apply a Rule script on), without using a static (am thinking of using this in a web app)?
I've seen the use compiled delegates -- but that was for the previous version of Mono.CSharp, and it doesn't seem to work any longer.
Anybody have a suggestion on how to do this with the current version?
Thanks very much.
References:
* Injecting a variable into the Mono.CSharp.Evaluator (runtime compiling a LINQ query from string)
* http://naveensrinivasan.com/tag/mono/
I know it's almost 9 years later, but I think I found a viable solution to inject local variables. It is using a static variable but can still be used by multiple evaluators without collision.
You can use a static Dictionary<string, object> which holds the reference to be injected. Let's say we are doing all this from within our class CsharpConsole:
public class CsharpConsole {
public static Dictionary<string, object> InjectionRepository {get; set; } = new Dictionary<string, object>();
}
The idea is to temporarily place the value in there with a GUID as key so there won't be any conflict between multiple evaluator instances. To inject do this:
public void InjectLocal(string name, object value, string type=null) {
var id = Guid.NewGuid().ToString();
InjectionRepository[id] = value;
type = type ?? value.GetType().FullName;
// note for generic or nested types value.GetType().FullName won't return a compilable type string, so you have to set the type parameter manually
var success = _evaluator.Run($"var {name} = ({type})MyNamespace.CsharpConsole.InjectionRepository[\"{id}\"];");
// clean it up to avoid memory leak
InjectionRepository.Remove(id);
}
Also for accessing local variables there is a workaround using Reflection so you can have a nice [] accessor with get and set:
public object this[string variable]
{
get
{
FieldInfo fieldInfo = typeof(Evaluator).GetField("fields", BindingFlags.NonPublic | BindingFlags.Instance);
if (fieldInfo != null)
{
var fields = fieldInfo.GetValue(_evaluator) as Dictionary<string, Tuple<FieldSpec, FieldInfo>>;
if (fields != null)
{
if (fields.TryGetValue(variable, out var tuple) && tuple != null)
{
var value = tuple.Item2.GetValue(_evaluator);
return value;
}
}
}
return null;
}
set
{
InjectLocal(variable, value);
}
}
Using this trick, you can even inject delegates and functions that your evaluated code can call from within the script. For instance, I inject a print function which my code can call to ouput something to the gui console window:
public delegate void PrintFunc(params object[] o);
public void puts(params object[] o)
{
// call the OnPrint event to redirect the output to gui console
if (OnPrint!=null)
OnPrint(string.Join("", o.Select(x => (x ?? "null").ToString() + "\n").ToArray()));
}
This puts function can now be easily injected like this:
InjectLocal("puts", (PrintFunc)puts, "CsInterpreter2.PrintFunc");
And just be called from within your scripts:
puts(new object[] { "hello", "world!" });
Note, there is also a native function print but it directly writes to STDOUT and redirecting individual output from multiple console windows is not possible.
By default, WCF deserializes missing elements into default values like null, 0 or false. The problem with this approach is that if it's a basic type like number 0 I'm not sure whether it means the real value sent by an external system or a default value generated by WCF.
So my question is: Is it possible to find out at run-time whether the default value means "I didn't send anything".
This is crucial because we can't update and overwrite existing data in the database with the default values just because the external system didn't send a particular element this time (data corruption).
Microsoft's short answer is "It is up to the receiving endpoint to appropriately interpret a missing element."
Data member default values
http://msdn.microsoft.com/en-us/library/aa347792.aspx
Can somebody please clarify what's that supposed to mean?
Thanks
If you define your data members as properties, you can use whether the setter was called or not to decide whether some value was sent. The code below shows one data contract which knows whether it deserialized its fields.
public class Post_51ca1ead_2f0a_4912_a451_374daab0101b
{
[DataContract(Name = "Person", Namespace = "")]
public class Person
{
string name;
int age;
bool nameWasSent;
bool ageWasSent;
[DataMember]
public string Name
{
get
{
return this.name;
}
set
{
this.nameWasSent = true;
this.name = value;
}
}
[DataMember]
public int Age
{
get
{
return this.age;
}
set
{
this.ageWasSent = true;
this.age = value;
}
}
[OnDeserializing]
void OnDeserializing(StreamingContext ctx)
{
this.ageWasSent = false;
this.nameWasSent = false;
}
public override string ToString()
{
return string.Format("Person[Name={0},Age={1}]",
nameWasSent ? name : "UNSPECIFIED",
ageWasSent ? age.ToString() : "UNSPECIFIED");
}
}
public static void Test()
{
MemoryStream ms = new MemoryStream();
DataContractSerializer dcs = new DataContractSerializer(typeof(Person));
dcs.WriteObject(ms, new Person { Name = "John", Age = 30 });
Console.WriteLine(Encoding.UTF8.GetString(ms.ToArray()));
string noAge = "<Person><Name>John</Name></Person>";
ms = new MemoryStream(Encoding.UTF8.GetBytes(noAge));
object p = dcs.ReadObject(ms);
Console.WriteLine("No age: {0}", p);
string noName = "<Person><Age>45</Age></Person>";
ms = new MemoryStream(Encoding.UTF8.GetBytes(noName));
p = dcs.ReadObject(ms);
Console.WriteLine("No name: {0}", p);
}
}
As part of my project, I am trying to build a web UI where user will select a method and pass the values. My program should be able to call the method dynamically and build a parameter list on runtime to pass it to the method.
I have created a comma separated list (string) of key and value pairs. This key/value pair is nothing but the parameter name and value of my method (methodname stored in a variable). Example: string params = "ID:123;Name:Garry;Address:addressObject;AddressLine:108 Plaza Lane;City:Avenel;State:NJ;Zip:07001;". Where ID and Name are simple string varaibles while Address is user defined type. What follows after Address i.e. AddressLine, City, State and Zip is elements of Address object. And my method definition is
public string GetInfo(string ID, string Name, Address addressObject)
{
//return something;
}
I am dynamically calling the method (GetInfo) that is stored in sMethodName variable using DynamicProxy like :
string sMethodName = "GetInfo";
object result = (object) proxy.CallMethod(sMethodName, arguments);
Challenge is how to pass the argument list dynamically? Till now I am just able to extract the values from the csv variable into NamedValueCollection. Here is the code:
public static void StoreParameterValues(string param)
{
nvc = new NameValueCollection();
param = param.TrimEnd(';');
string[] parameters = param.Split(new char[] { ';' });
foreach (string val in parameters)
{
string[] keyValue = val.Split(new char[] { ':' });
nvc.Add(keyValue[0], keyValue[1]);
}
}
..and here is the code that tries to build the parameter:
string methodName = "GetInfo";
DynamicProxyFactory factory = new DynamicProxyFactory("http://../myservice.svc");
string sContract = "";
foreach (ServiceEndpoint endpoint in factory.Endpoints)
{
sContract = endpoint.Contract.Name;
}
DynamicProxy proxy = factory.CreateProxy(sContract);
string[] values = null;
// Create the parameter list
object[] arguments = new object[nvc.Count];
int i = -1;
foreach (string key in nvc.Keys)
{
values = nvc.GetValues(key);
foreach (string value in values)
{
arguments[++i] = value;
}
}
object result = (object) proxy.CallMethod(methodName, arguments);
The above code works if I have simple primitive types but not sure how can I build the logic for any other userdefined types. How can I create a object dynamically of type stored in a variable? Not sure if I was able to put my question correctly. I hope so :)
Edit: 01/19/2011: Applied the suggestion from Chris - using Reflection instead of ComponentModel.
I have converted the code to make it more generic. This works now for all primitive and custom types (resursion). Code snippet below:
private object BuildParameterList(Type type)
{
object item = new object();
item = Activator.CreateInstance(type);
PropertyInfo[] propArray = type.GetProperties(BindingFlags.Public|BindingFlags.Instance);
for (int i = 0; i < propArray.Length; i++)
{
PropertyInfo pi = (PropertyInfo)propArray[i];
////Check for custom type
if (IsCustomType(pi.PropertyType))
{
object item1 = BuildParameterList(pi.PropertyType);
pi.SetValue(item, item1, null);
}
else
{
if (property.ContainsKey(pi.Name))
{
pi.SetValue(item, Convert.ChangeType(property[pi.Name], pi.PropertyType), null);
}
}
}
return item;
}
But if one of the property is Color (I just tested with Color type, will fail with other system types aswell-i guess), then it fails at the following line. Not sure how to handle system types - Color or something similar.
pi.SetValue(item, Convert.ChangeType(property[pi.Name], pi.PropertyType), null);
Can you not find what types are expected by the method, by inspecting its ParameterInfos:
endpoint.Contract.ContractType.GetMethod(methodName).GetParameters();
and then instantiating the custom types using:
Activator.CreateInstance(parameterType);