JarCastingjackson-module-caseclass
Features
- If one field present in json, just deserialize it.
- If one field not present in json, but the case class has default value, deserialize it as the case class default value.
- If one field not present in json, and the case class doesn't has default value, deserialize it as a zero value.
- Use scala reflect instead of java reflect to constract JavaType, so that jackson-module-caseclass can extract type parameter correctly https://github.com/FasterXML/jackson-module-scala/issues/62.
Zero value
For some scala type, if jackson-module-caseclass doesn't know what a field value should be set, it will be deserialized as a zero value so that we can avoid NullPointerException at most case.
- Number(Int, Long, Char ...): 0
- Boolean: false
- Option: None
collection.Map: Map.empty(you should set it as default value in case class definition)Iterable: Nil(same as above)
Dependency
sbt
libraryDependencies += "com.github.changvvb" %% "jackson-module-caseclass" % "1.1.1"
Usage
1. Use @CaseClassDeserialize
import com.fasterxml.jackson.module.caseclass.annotation.CaseClassDeserialize
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.databind.annotation.JsonDeserialize
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
import com.fasterxml.jackson.module.caseclass.mapper.CaseClassObjectMapper
@CaseClassDeserialize()
case class TestCaseClass(
intValue:Int,
stringValue:String,
seqValue:Seq[_],
optionValue:Option[_] = None)
val mapper = new ObjectMapper with ScalaObjectMapper with CaseClassObjectMapper
val json =
"""
|{
| "intValue": 3,
| "stringValue": "some strings"
|}
""".stripMargin
mapper.readValue[TestCaseClass](json)
2. Use @JsonDeserialize
import com.fasterxml.jackson.module.caseclass.deser.CaseClassDeserializer
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.databind.annotation.JsonDeserialize
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
import com.fasterxml.jackson.module.caseclass.mapper.CaseClassObjectMapper
class MyDeserializer extends CaseClassDeserializer[TestCaseClass]
@JsonDeserialize(using = classOf[MyDeserializer])
case class TestCaseClass(
intValue:Int,
stringValue:String,
seqValue:Seq[_],
optionValue:Option[_] = None)
val mapper = new ObjectMapper with ScalaObjectMapper with CaseClassObjectMapper
val json =
"""
|{
| "intValue": 3,
| "stringValue": "some strings"
|}
""".stripMargin
mapper.readValue[TestCaseClass](json)
3. Use registerCaseClassDeserializer()
import com.fasterxml.jackson.module.caseclass.deser.CaseClassDeserializer
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
import com.fasterxml.jackson.module.caseclass.mapper.CaseClassObjectMapper
case class TestCaseClass(
intValue:Int,
stringValue:String,
seqValue:Seq[_],
optionValue:Option[_] = None)
val mapper = new ObjectMapper with ScalaObjectMapper with CaseClassObjectMapper
mapper.registerCaseClassDeserializer[TestCaseClass]()
val json =
"""
|{
| "intValue": 3,
| "stringValue": "some strings"
|}
""".stripMargin
mapper.readValue[TestCaseClass](json)
4. Enable all case class
import com.fasterxml.jackson.module.caseclass.deser.CaseClassDeserializer
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
import com.fasterxml.jackson.module.caseclass.mapper.CaseClassObjectMapper
case class TestCaseClass(
intValue:Int,
stringValue:String,
seqValue:Seq[_],
optionValue:Option[_] = None)
val mapper = new ObjectMapper with ScalaObjectMapper with CaseClassObjectMapper
mapper.setAllCaseClassEnabled(true)
val json =
"""
|{
| "intValue": 3,
| "stringValue": "some strings"
|}
""".stripMargin
mapper.readValue[TestCaseClass](json)