正在寻找一个使用jackson和scala进行多态序列化反序列化的好例子
正在寻找一个使用jackson和scala进行多态序列化反序列化的好例子 有一个例外: 线程“main”中出现异常 块引用 org.codehaus.jackson.map.exc.UnrecognizedPropertyException: 未识别的野外“动物”(动物园级),未标记为可忽略 尝试以下代码后:正在寻找一个使用jackson和scala进行多态序列化反序列化的好例子,scala,jackson,Scala,Jackson,正在寻找一个使用jackson和scala进行多态序列化反序列化的好例子 有一个例外: 线程“main”中出现异常 块引用 org.codehaus.jackson.map.exc.UnrecognizedPropertyException: 未识别的野外“动物”(动物园级),未标记为可忽略 尝试以下代码后: import org.codehaus.jackson.annotate.{ JsonTypeInfo, JsonSubTypes } import org.codehau
import org.codehaus.jackson.annotate.{ JsonTypeInfo, JsonSubTypes }
import org.codehaus.jackson.annotate.JsonSubTypes.Type
@JsonTypeInfo(
use = JsonTypeInfo.Id.NAME,
include= JsonTypeInfo.As.PROPERTY,
property = "type"
)
@JsonSubTypes(Array(
new Type(value= classOf[Cat] , name = "cat"),
new Type(value= classOf[Dog] , name = "dog")
)
)
abstract class Animal {
val name:String = "NoName"
}
class Cat extends Animal{
val favoriteToy = "edi"
}
class Dog extends Animal{
val breed = "German Shepherd"
val color = "brown"
}
class Zoo {
val animals = new scala.collection.mutable.ListBuffer[Animal]
}
import org.codehaus.jackson.map.ObjectMapper
object Foo {
def main (args:Array[String]) {
val mapper = new ObjectMapper()
mapper.setPropertyNamingStrategy(CamelCaseNamingStrategy )
val source = scala.io.Source.fromFile("input.json" )
val input = source.mkString
source.close
val zoo = mapper.readValue(input,classOf[Zoo])
println(mapper.writeValueAsString(zoo))
}
import org.codehaus.jackson.map.introspect.{AnnotatedField, AnnotatedMethod}
import org.codehaus.jackson.map.{MapperConfig, PropertyNamingStrategy}
object CamelCaseNamingStrategy extends PropertyNamingStrategy{
override def nameForGetterMethod (config: MapperConfig[_], method: AnnotatedMethod, defaultName: String) =
{
translate(defaultName)
}
override def nameForSetterMethod (config: MapperConfig[_], method: AnnotatedMethod, defaultName: String) = {
translate(defaultName)
}
override def nameForField (config: MapperConfig[_], field: AnnotatedField, defaultName: String) = {
translate(defaultName)
}
def translate(defaultName:String) = {
val nameChars = defaultName.toCharArray
val nameTranslated = new StringBuilder(nameChars.length*2)
for ( c <- nameChars){
if (Character.isUpperCase(c)){
nameTranslated.append("_")
}
nameTranslated.append( Character.toLowerCase(c))
}
nameTranslated.toString
}
}
好的,这里是一个scala的工作示例,基于: 文件:input.json{“动物”:[ {“类型”:“狗”,“名称”:“穗”,“品种”:“杂种”,“颜色”:“红色”}, {“类型”:“猫”,“名字”:“毛茸茸的”,“宠儿玩具”:“蜘蛛环”} ]}
如果您在Scala中进行多态反序列化,我强烈建议您使用case类和Jackson的Scala模块
object Test {
import com.fasterxml.jackson.annotation.JsonSubTypes.Type
import com.fasterxml.jackson.annotation.{JsonSubTypes, JsonTypeInfo}
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
@JsonTypeInfo(
use = JsonTypeInfo.Id.NAME,
include = JsonTypeInfo.As.PROPERTY,
property = "type"
)
@JsonSubTypes(Array(
new Type(value = classOf[Cat], name = "cat"),
new Type(value = classOf[Dog], name = "dog")
))
trait Animal
case class Dog(name: String, breed: String, leash_color: String) extends Animal
case class Cat(name: String, favorite_toy: String) extends Animal
case class Zoo(animals: Iterable[Animal])
def main(args: Array[String]): Unit = {
val objectMapper = new ObjectMapper with ScalaObjectMapper
objectMapper.registerModule(DefaultScalaModule)
val dogStr = """{"type": "dog", "name": "Spike", "breed": "mutt", "leash_color": "red"}"""
val catStr = """{"type": "cat", "name": "Fluffy", "favorite_toy": "spider ring"}"""
val zooStr = s"""{"animals":[$dogStr, $catStr]}"""
val zoo = objectMapper.readValue[Zoo](zooStr)
println(zoo)
// Prints: Zoo(List(Dog(Spike,mutt,red), Cat(Fluffy,spider ring)))
}
}
Nate,你在什么版本的Jackson和Scala上运行这个?我得到com.fasterxml.jackson.databind.JsonMappingException:无法构造TestJackson$Animal的实例,问题:抽象类型需要映射到具体类型,具有自定义反序列化器,或者使用最新的Jackson 2.4.3在Scala 2.10.4上的其他类型信息进行实例化。我已经更新了我的帖子,以包含特定的导入(该错误听起来像是不正确的导入)。这应该适用于Scala 2.9+和Jackson 2.2+的所有版本(如果不是更早的话)。我特别使用了Scala 2.11.2和Jackson 2.4.3。只要有一个jackson模块,scala jar就可以为这个组合构建,它应该可以工作。你可以在这里找到它们:
import org.codehaus.jackson.annotate.JsonSubTypes.Type
import org.codehaus.jackson.annotate.{JsonSubTypes, JsonTypeInfo}
@JsonTypeInfo(
use = JsonTypeInfo.Id.NAME,
include= JsonTypeInfo.As.PROPERTY,
property = "type"
)
@JsonSubTypes(Array(
new Type(value= classOf[Cat] , name = "cat"),
new Type(value= classOf[Dog] , name = "dog")
)
)
abstract class Animal {
var name:String =""
}
class Dog extends Animal{
var breed= "German Shepherd"
var color = "brown"
}
class Cat extends Animal{
var favoriteToy:String = "nothing"
}
class Zoo {
var animals = new Array[Animal](5)
}
import org.codehaus.jackson.annotate.JsonAutoDetect.Visibility
import org.codehaus.jackson.annotate.JsonMethod
import org.codehaus.jackson.map.{DeserializationConfig, ObjectMapper}
object Foo {
def main (args:Array[String]) {
val mapper = new ObjectMapper().setVisibility(JsonMethod.FIELD,Visibility.ANY)
mapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES,false)
val source = scala.io.Source.fromFile("/input.json" )
val input = source.mkString
println("input " + input)
source.close
val zoo = mapper.readValue(input,classOf[Zoo])
println(mapper.writeValueAsString(zoo))
}
}
object Test {
import com.fasterxml.jackson.annotation.JsonSubTypes.Type
import com.fasterxml.jackson.annotation.{JsonSubTypes, JsonTypeInfo}
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.module.scala.DefaultScalaModule
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
@JsonTypeInfo(
use = JsonTypeInfo.Id.NAME,
include = JsonTypeInfo.As.PROPERTY,
property = "type"
)
@JsonSubTypes(Array(
new Type(value = classOf[Cat], name = "cat"),
new Type(value = classOf[Dog], name = "dog")
))
trait Animal
case class Dog(name: String, breed: String, leash_color: String) extends Animal
case class Cat(name: String, favorite_toy: String) extends Animal
case class Zoo(animals: Iterable[Animal])
def main(args: Array[String]): Unit = {
val objectMapper = new ObjectMapper with ScalaObjectMapper
objectMapper.registerModule(DefaultScalaModule)
val dogStr = """{"type": "dog", "name": "Spike", "breed": "mutt", "leash_color": "red"}"""
val catStr = """{"type": "cat", "name": "Fluffy", "favorite_toy": "spider ring"}"""
val zooStr = s"""{"animals":[$dogStr, $catStr]}"""
val zoo = objectMapper.readValue[Zoo](zooStr)
println(zoo)
// Prints: Zoo(List(Dog(Spike,mutt,red), Cat(Fluffy,spider ring)))
}
}