Jackson remove "e" from BigDecimal [duplicate] - jackson

I am using a library com.fasterxml.jackson library for JsonSchema,
I am creating an IntegerSchema object, when I set range for integer schema using below code:
main(){
IntegerSchema intSchema = new IntegerSchema();
// setMaximum accepts Double object
intSchema.setMaximum(new Double(102000000));
// setMaximum accepts Double object
intSchema.setMinimum(new Double(100));
printJsonSchema(intSchema);
}
public void printJsonSchema(JsonSchema schema){
ObjectMapper mapper = new ObjectMapper();
try {
logger.info(mapper.writeValueAsString(schema));
} catch (JsonProcessingException e) {
throw new IllegalStateException(e);
}
}
When I convert IntegerSchema to string using ObjectMapper getting below response:
{"type":"integer","maximum":1.02E8,"minimum":100.0}
maximum and minimum values are getting converted to scientific notation.
But I need output in non scientific notation as below:
{"type":"integer","maximum":102000000,"minimum":100}
I cannot change IntegerSchema class.
Please suggest how to get the required output without extending IntegerSchema class?
Thanks in advance

this is a java issue somewhat I believe. If you debug your program, your Double will always be displayed scientifically, so what we'll want is to force it into a String. This can be achieved in Java in multiple ways, and you can look it up here:
How to print double value without scientific notation using Java?
In terms of your specific question about Jackson, I've written up some code for you:
public class ObjectMapperTest {
public static void main(String[] args) throws JsonProcessingException {
IntegerSchema schema = new IntegerSchema();
schema.type = "Int";
schema.max = 10200000000d;
schema.min = 100d;
ObjectMapper m = new ObjectMapper();
System.out.println(m.writeValueAsString(schema));
}
public static class IntegerSchema {
#JsonProperty
String type;
#JsonProperty
double min;
#JsonProperty
#JsonSerialize(using=MyDoubleDesirializer.class)
double max;
}
public static class MyDoubleDesirializer extends JsonSerializer<Double> {
#Override
public void serialize(Double value, JsonGenerator gen, SerializerProvider serializers)
throws IOException, JsonProcessingException {
// TODO Auto-generated method stub
BigDecimal d = new BigDecimal(value);
gen.writeNumber(d.toPlainString());
}
}
}
The trick is to register a custom Serializer for your Double value. This way, you can control what you want.
I am using the BigDecimal value to create a String representation of your Double. The output then becomes (for the specific example):
{"type":"Int","min":100.0,"max":10200000000}
I hope that solves your problem.
Artur

Feature.WRITE_BIGDECIMAL_AS_PLAIN
set this for your Object Mapper

I know I am answering late, but something I faced may help other
While converting a BigDecimal I have faced below is working
mapper = mapper.setNodeFactory(JsonNodeFactory.withExactBigDecimals(true));
while this is not working for me
mapper.configure(JsonGenerator.Feature.WRITE_BIGDECIMAL_AS_PLAIN, true);

Update for Jakson 2.9.10:
Property WRITE_BIGDECIMAL_AS_PLAIN replaced to com.fasterxml.jackson.core.JsonGenerator. You could use:
mapper.enable(JsonGenerator.Feature.WRITE_BIGDECIMAL_AS_PLAIN);

If you are using ValueToTree then no need of any factory settings. only problem with ValueToTree is it is converting as TextNode (String Fromat), So if you have any logic based on ObjectNodes it will not work

You should use
mapper.configure(DeserializationFeature.USE_BIG_DECIMAL_FOR_FLOATS, true);
To avoid scientific notation on floating numbers.
You can find an example below.
ObjectMapper mapper = new ObjectMapper();
mapper.configure(DeserializationFeature.USE_BIG_DECIMAL_FOR_FLOATS, true);
String test ="{\"doubleValue\" : 0.00001}";
try {
System.out.println(mapper.readTree(test).toPrettyString());
} catch (JsonProcessingException e) {
e.printStackTrace();
}
Output
{
"doubleValue" : 0.00001
}

Related

Change the axis of lat long when using JTS jackson

I am using locationtech JTS library in spring boot with jackson as json serializer and a Jts-data-type module with supports serializing JTS geometry.The issue which i am facing is the axis order of coordinates when json is returned is long lat instead of lat long there is a solution on stackoverflow https://stackoverflow.com/a/29634389/1574921 i want to know if there is any other way to achieve this functionality instead of always applying InvertCoordinateFilter whenever i create a functionality.
Below is the code which i am using
ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new JtsModule());
double lat = 32.3456789;
double lng = 72.423434;
GeometryFactory gf = new GeometryFactory();
Point point = gf.createPoint(new Coordinate(lng,lat ));
String json = mapper.writeValueAsString(point);
System.out.println(json);
and the output is
{"type":"Point","coordinates":[72.423434,32.3456789]}
and i want output to be
{"type":"Point","coordinates":[32.3456789,72.423434]}
There is no way to tweak GeometrySerializer, since the order is hardcoded in lines 174-175.
In order to avoid writing a serializer by yourself, you could just copy GeometrySerializer and invert those two lines, but you would effectively not be using the official jts-data-type, and future modifications on the library would not be reflected in your copied serializer unless you do it manually.
Alternatively, just decorate the GeometrySerializer and use the InverseCoordinateFilter before calling it:
public static class CustomGeometrySerializer extends JsonSerializer<Geometry> {
private GeometrySerializer innerSerializer;
private InvertCoordinateFilter inverter = new InvertCoordinateFilter();
public CustomGeometrySerializer() {
this(new GeometrySerializer());
}
public CustomGeometrySerializer(GeometrySerializer innerSerializer) {
this.innerSerializer = innerSerializer;
}
#Override
public void serialize(Geometry value, JsonGenerator jgen,
SerializerProvider provider) throws IOException {
// Create a new Geometry to avoid mutating the original one
Geometry newValue = value.copy();
newValue.apply(inverter);
innerSerializer.serialize(newValue, jgen, provider);
}
private static class InvertCoordinateFilter implements CoordinateFilter {
public void filter(Coordinate coord) {
double oldX = coord.x;
coord.x = coord.y;
coord.y = oldX;
}
}
}
Now, instead of registering JtsModule, create a module yourself with your deserializer:
ObjectMapper mapper = new ObjectMapper();
SimpleModule inverseJtsModule = new SimpleModule();
inverseJtsModule.addSerializer(Geometry.class, new CustomGeometrySerializer());
mapper.registerModule(inverseJtsModule);
double lat = 32.3456789;
double lng = 72.423434;
GeometryFactory gf = new GeometryFactory();
Point point = gf.createPoint(new Coordinate(lng, lat));
String json = mapper.writeValueAsString(point);
System.out.println(json);
You can now safely serialize your geometries without explicitly inverting each one. For deserialization, you can use the same approach, decorating GeometryDeserializer.

Creating JSON without quotes

A library is using Map to use some extra information. This map eventually is being converted a JSON object and I need to set request information to display for debugging purposes as this:
map.put("request", requestString);
I am considering to use Jackson specifically to create a JSON without quotes and want to set as requestString.
I am building necessary information regarding Request and building a Map including request headers, parameters, method etc.
Jackson is creating perfectly valid JSON with quotes but when I set this generated value inside map, It is displayed ugly because of having escaped quotes.
So Jackson is creating this:
{
method : "POST",
path : "/register"
}
When I set this in map, it turns to this:
{
method : \"POST\",
path : \"/register\"
}
Consider this as a huge map including all parameters and other information about request.
What I would like to want this:
{
method : POST,
path : /register
}
I know that this is not a valid JSON but I am using this as a String to a Map which is accepting String values.
public class UnQuotesSerializer extends NonTypedScalarSerializerBase<String>
{
public UnQuotesSerializer() { super(String.class); }
/**
* For Strings, both null and Empty String qualify for emptiness.
*/
#Override
public boolean isEmpty(String value) {
return (value == null) || (value.length() == 0);
}
#Override
public void serialize(String value, JsonGenerator jgen, SerializerProvider provider) throws IOException {
jgen.writeRawValue(value);
}
#Override
public JsonNode getSchema(SerializerProvider provider, Type typeHint) {
return createSchemaNode("string", true);
}
#Override
public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType typeHint) throws JsonMappingException {
if (visitor != null) visitor.expectStringFormat(typeHint);
}
}
and
ObjectMapper objectMapper = new ObjectMapper();
SimpleModule module = new SimpleModule("UnQuote");
module.addSerializer(new UnQuotesSerializer());
objectMapper.configure(JsonGenerator.Feature.QUOTE_FIELD_NAMES, false);
objectMapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
objectMapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_CONTROL_CHARS, true);
objectMapper.registerModule(module);
This is generating without quotes strings.
The following test passes (Jackson 2.5.0)
#Test
public void test() throws Exception {
ObjectMapper mapper = new ObjectMapper();
Map map = new HashMap();
map.put("method", "POST");
map.put("request", "/register");
String s = mapper.writeValueAsString(map);
Map map2 = mapper.readValue(s, Map.class);
Assert.assertEquals(map, map2);
}
so your pseudo JSON without quotes does not seem the way to go

Serialization of Keys with Circular References using Jackson

I am trying to serialize a HashMap from Objects to Strings, but the specific Object has a reference to the current class leading to an infinite recursion, which doesn't seem to be solved with the usual JsonIdentifyInfo annotation. Here's an example:
public class CircularKey {
public void start() throws IOException {
ObjectMapper mapper = new ObjectMapper();
Cat cat = new Cat();
// Encode
String json = mapper.writeValueAsString(cat);
System.out.println(json);
// Decode
Cat cat2 = mapper.readValue(json, Cat.class);
System.out.println(mapper.writeValueAsString(cat2));
}
}
#JsonIdentityInfo(generator = ObjectIdGenerators.IntSequenceGenerator.class, property = "#id")
#JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "#class")
class Mouse {
int id;
#JsonProperty
Cat cat;
}
#JsonIdentityInfo(generator = ObjectIdGenerators.IntSequenceGenerator.class, property = "#id")
#JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "#class")
class Cat {
int id;
#JsonSerialize(keyUsing = MouseMapKeySerializer.class)
#JsonDeserialize(keyUsing = MouseMapKeyDeserializer.class)
#JsonProperty
HashMap<Mouse, String> status = new HashMap<Mouse, String>();
public Cat() {
Mouse m = new Mouse();
m.cat = this;
status.put(m, "mike");
}
}
Here's the serializer/deserializer for the key:
class MouseMapKeySerializer extends JsonSerializer<Mouse> {
static ObjectMapper mapper = new ObjectMapper();
#Override
public void serialize(Mouse value, JsonGenerator generator,
SerializerProvider provider) throws IOException,
JsonProcessingException {
String json = mapper.writeValueAsString(value);
generator.writeFieldName(json);
}
}
class MouseMapKeyDeserializer extends KeyDeserializer {
static ObjectMapper mapper = new ObjectMapper();
#Override
public Mouse deserializeKey(String c, DeserializationContext ctx)
throws IOException, JsonProcessingException {
return mapper.readValue(c, Mouse.class);
}
}
If I switch the map to HashMap (String,Object) it works but I cannot change the original mapping. Any ideas?
It looks like you found your answer at http://jackson-users.ning.com/forum/topics/serializing-hashmap-with-object-key-and-recursion. This doesn't seem to be possible because:
Complex keys are tricky, and it is not a use case I ever considered. Then again, there is nothing specifically preventing use of standard components; main concern was just the limitations than JSON has (must be String-value, JsonParser/JsonGenerator expose keys as different tokens).
There is no explicit support for either polymorphic types or object ids for Object keys. Standard serializers/deserializers are mostly for relatively simple types that can be easily and reliably converted to/from Strings; numbers, Dates, UUIDs.
So: unlike with value handlers, where modular design (with separation of TypeSerializer/JsonSerializer) makes sense, I think what you need to do is to have custom (de)serializers that handle all aspects. You should be able to use code from existing value (de)serializers, type (de)serializers, but not classes themselves.
Your use case does sound interesting, but for better or worse, it is pushing the envelope quite a bit. :-)

Jackson vector serialization exception

I have the following code with a simple class and a method for writing and then reading:
ObjectMapper mapper = new ObjectMapper();
try{
DataStore testOut = new DataStore();
DataStore.Checklist ch1 = testOut.addChecklist();
ch1.SetTitle("Checklist1");
String output = mapper.writeValueAsString(testOut);
JsonNode rootNode = mapper.readValue(output, JsonNode.class);
Map<String,Object> userData = mapper.readValue(output, Map.class);
}
public class DataStore {
public static class Checklist
{
public Checklist()
{
}
private String _title;
public String GetTitle()
{
return _title;
}
public void SetTitle(String title)
{
_title = title;
}
}
//Checklists
private Vector<Checklist> _checklists = new Vector<Checklist>();
public Checklist addChecklist()
{
Checklist ch = new Checklist();
ch.SetTitle("New Checklist");
_checklists.add(ch);
return ch;
}
public Vector<Checklist> getChecklists()
{
return _checklists;
}
public void setChecklists(Vector<Checklist> checklists)
{
_checklists = checklists;
}
}
The line:
String output = mapper.writeValueAsString(testOut);
causes an exception that has had me baffled for hours and about to abandon using this at all.
Any hints are appreciated.
Here is the exception:
No serializer found for class DataStore$Checklist and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: DataStore["checklists"]->java.util.Vector[0])
There are multiple ways to do it, but I will start with what you are doing wrong: your naming of getter and setter method is wrong -- in Java one uses "camel-case", so you should be using "getTitle". Because of this, properties are not found.
Besides renaming methods to use Java-style names, there are alternatives:
You can use annotation JsonProperty("title") for GetTitle(), so that property is recognized
If you don't want the wrapper object, you could alternatively just add #JsonValue for GetTitle(), in which case value used for the whole object would be return value of that method.
The answer seems to be: You can't do that with Json. I've seen comments in the Gson tutorial as well, that state that some serialization just doesn't work. I downloaded XStream and spat it out with XML in a few minutes of work and a lot less construction around what I really wanted to persist. In the process, I was able to delete a lot of code.

how to parse non-string values in Opencsv HeaderColumnNameMappingStrategy

I'm using a HeaderColumnNameMappingStrategy to map a csv file with a header into a JavaBean. String values parse fine but any "true" or "false" value in csv doesn't map to JavaBean and I get the following exception from the PropertyDescriptor:
java.lang.IllegalArgumentException: argument type mismatch
The code where it occurs is in CsvToBean, line 64:
protected T processLine(MappingStrategy<T> mapper, String[] line) throws
IllegalAccessException, InvocationTargetException, InstantiationException, IntrospectionException {
T bean = mapper.createBean();
for(int col = 0; col < line.length; col++) {
String value = line[col];
PropertyDescriptor prop = mapper.findDescriptor(col);
if (null != prop) {
Object obj = convertValue(value, prop);
// this is where exception is thrown for a "true" value in csv
prop.getWriteMethod().invoke(bean, new Object[] {obj});
}
}
return bean;
}
protected PropertyEditor getPropertyEditor(PropertyDescriptor desc) throws
InstantiationException, IllegalAccessException {
Class<?> cls = desc.getPropertyEditorClass();
if (null != cls) return (PropertyEditor) cls.newInstance();
return getPropertyEditorValue(desc.getPropertyType());
}
I can confirm (via debugger) that the setter method id correctly retrieved at this point.
The problem occurs in desc.getPropertyEditorClass() since it returns null. I assumed primitive types and its wrappers are supported. Are they not?
I've run into this same issue. The cleanest way is probably to override getPropertyEditor like pritam did above and return a custom PropertyEditor for your particular object. The quick and dirty way would be to override convertValue in anonymous class form, like this:
CsvToBean<MyClass> csvToBean = new CsvToBean<MyClass>(){
#Override
protected Object convertValue(String value, PropertyDescriptor prop) throws InstantiationException,IllegalAccessException {
if (prop.getName().equals("myWhatever")) {
// return an custom object based on the incoming value
return new MyWhatever((String)value);
}
return super.convertValue(value, prop);
}
};
This is working fine for me with OpenCSV 2.3. Good luck!
I resolved this by extending CsvToBean and adding my own PropertyEditors. Turns out opencsv just supports primitive types and no wrappers.
Pritam's answer is great and this is a sample for dealing with datetime format.
PropertyEditorManager.registerEditor(java.util.Date.class, DateEditor.class);
You should write your own editor class like this:
public class DateEditor extends PropertyEditorSupport{
public static final SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
#Override
public void setAsText(String text){
setValue(sdf.parse(text));}
}