avoid reparsing numbers when serializing

Update StringBasedNumericNode.scala

rework

Update JacksonJson.scala

add containsEOrDot

play-json/jvm/src/main/scala/play/api/libs/json/jackson/JacksonJson.scala

@@ -6,6 +6,7 @@ package play.api.libs.json.jackson
 
 import java.io.InputStream
 import java.io.StringWriter
+import java.math.BigInteger
 
 import scala.annotation.switch
 import scala.annotation.tailrec
@@ -26,6 +27,7 @@ import com.fasterxml.jackson.databind._
 import com.fasterxml.jackson.databind.`type`.TypeFactory
 import com.fasterxml.jackson.databind.deser.Deserializers
 import com.fasterxml.jackson.databind.module.SimpleModule
+import com.fasterxml.jackson.databind.node.BigIntegerNode
 import com.fasterxml.jackson.databind.ser.Serializers
 
 import play.api.libs.json._
@@ -67,12 +69,8 @@ sealed class PlayJsonMapperModule(jsonConfig: JsonConfig) extends SimpleModule("
 // -- Serializers.
 
 private[jackson] class JsValueSerializer(jsonConfig: JsonConfig) extends JsonSerializer[JsValue] {
-  import java.math.BigInteger
   import java.math.{ BigDecimal => JBigDec }
 
-  import com.fasterxml.jackson.databind.node.BigIntegerNode
-  import com.fasterxml.jackson.databind.node.DecimalNode
-
   private def stripTrailingZeros(bigDec: JBigDec): JBigDec = {
     val stripped = bigDec.stripTrailingZeros
     if (jsonConfig.bigDecimalSerializerConfig.preserveZeroDecimal && bigDec.scale > 0 && stripped.scale <= 0) {
@@ -96,10 +94,10 @@ private[jackson] class JsValueSerializer(jsonConfig: JsonConfig) extends JsonSer
         val stripped = stripTrailingZeros(v.bigDecimal)
         val raw      = if (shouldWritePlain) stripped.toPlainString else stripped.toString
 
-        if (raw.indexOf('E') < 0 && raw.indexOf('.') < 0)
-          json.writeTree(new BigIntegerNode(new BigInteger(raw)))
+        if (containsEOrDot(raw))
+          json.writeTree(StringBasedNumericNode(raw))
         else
-          json.writeTree(new DecimalNode(new JBigDec(raw)))
+          json.writeTree(new BigIntegerNode(new BigInteger(raw)))
       }
 
       case JsString(v)  => json.writeString(v)
@@ -125,6 +123,16 @@ private[jackson] class JsValueSerializer(jsonConfig: JsonConfig) extends JsonSer
       case JsNull => json.writeNull()
     }
   }
+
+  private def containsEOrDot(s: String): Boolean = {
+    var i = 0
+    while (i < s.length) {
+      val c = s.charAt(i)
+      if (c == 'E' || c == '.') return true
+      i += 1
+    }
+    false
+  }
 }
 
 private[jackson] sealed trait DeserializerContext {

play-json/jvm/src/main/scala/play/api/libs/json/jackson/StringBasedNumericNode.scala

@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) from 2022 The Play Framework Contributors <https://github.com/playframework>, 2011-2021 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+package play.api.libs.json.jackson
+
+import com.fasterxml.jackson.core.{ JsonGenerator, JsonParser, JsonToken }
+import com.fasterxml.jackson.databind.SerializerProvider
+import com.fasterxml.jackson.databind.node.NumericNode
+
+import java.math.{ BigDecimal, BigInteger }
+
+/**
+ * A numeric node that is represented as a string.
+ *
+ * For internal use only. Some methods are not implemented and will throw an exception.
+ */
+private[jackson] case class StringBasedNumericNode(text: String) extends NumericNode {
+
+  override def numberType: JsonParser.NumberType = JsonParser.NumberType.BIG_DECIMAL
+
+  override def asText(): String = text
+
+  override def asToken(): JsonToken = JsonToken.VALUE_NUMBER_FLOAT
+
+  override def isIntegralNumber: Boolean = false
+
+  override def serialize(jgen: JsonGenerator, ctxt: SerializerProvider): Unit =
+    jgen.writeNumber(text)
+
+  override def numberValue: Number = throw new NotImplementedError
+
+  override def intValue: Int = throw new NotImplementedError
+
+  override def longValue: Long = throw new NotImplementedError
+
+  override def doubleValue: Double = throw new NotImplementedError
+
+  override def decimalValue: BigDecimal = throw new NotImplementedError
+
+  override def bigIntegerValue: BigInteger = throw new NotImplementedError
+
+  override def canConvertToInt: Boolean = false
+
+  override def canConvertToLong: Boolean = false
+}