Small Example of Jackson Scala Module?
41,410
Solution 1
Give this a shot:
val person = Person("fred", 25)
val mapper = new ObjectMapper()
mapper.registerModule(DefaultScalaModule)
val out = new StringWriter
mapper.writeValue(out, person)
val json = out.toString()
println(json)
val person2 = mapper.readValue(json, classOf[Person])
println(person2)
EDIT
Just be sure to declare the Person
class as top level as it will not work otherwise.
Solution 2
Here's a complete example:
package com.example.samples
import org.junit.Test
import com.fasterxml.jackson.databind.ObjectMapper
import org.springframework.context.annotation.Bean
import java.io.File
import com.fasterxml.jackson.module.scala.DefaultScalaModule
import java.io.StringWriter
class JacksonTest {
@Test
@throws[Exception] def jacksonTest(): Unit = {
//case class Person(var name: String = "", var age: Int = 0)
//case class Person(@Bean var name: String, @Bean var age: Int)
case class Person( name: String, age: Int )
val person = Person("fred", 25)
val mapper = new ObjectMapper()
mapper.registerModule(DefaultScalaModule)
val out = new StringWriter
mapper.writeValue(out, person)
val json = out.toString()
println(json)
val person2 = mapper.readValue(json, classOf[Person])
println(person2)
}
}
However, this fails at mapper.readValue.
Here's my config:
<!-- Jackson libraries for JSON marshalling and unmarshalling -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.2.3</version>
</dependency>
<!-- Jackson module for scala object marshalling and unmarshalling -->
<dependency>
<groupId>com.fasterxml.jackson.module</groupId>
<artifactId>jackson-module-scala_2.10</artifactId>
<version>2.2.2</version>
</dependency>
<!-- Scala Compiler -->
<dependency>
<groupId>org.scala-lang</groupId>
<artifactId>scala-compiler</artifactId>
<version>2.10.2</version>
</dependency>
Any ideas why this fails? I can't see a difference with the working example.
Author by
Greg
Updated on May 16, 2020Comments
-
Greg almost 4 years
Can anyone point me towards a simple example of Jackson serialization/deserialization with their Scala module for 2.10? I'm looking for reflection-based JSON not requiring field-by-field annotation or assignment and it seemed this could do that, but their documentation includes no examples.
If I have a case class:
case class Person(name:String, age:Int) val person = Person("Fred", 65)
So from their github readme:
val mapper = new ObjectMapper() mapper.registerModule(DefaultScalaModule)
OK, now what...? How to I convert p to/from JSON?