JsonSyntaxException Gson：应为BEGIN_OBJECT，但为STRING

Question

我一直在尝试解密json数据，然后使用GSON将其转换为Scala case类。

代码：

import com.google.gson.Gson

object DecryptQRData extends App {

  val key = "klix8TW3SMGtHLVO0ZbhwO8ggW0p+npHfB71epkvmE0="
  val data = "c3NbCs3KQ6uC9d1kplSOg78opMs5+jKB/n5O3D4ttLQaNfWeU/s3RxYqDMazA09gOhhUWkRHZo3xrsgv/x2zoQ=="
  val bytesArray: Array[Byte] = AES.decodeBase64(data)
  val finalData: Array[Byte] = AES.decrypt(bytesArray, key)

  val jsonString: String = new String(finalData)
  println(s"result: $jsonString")
  //result: "{\"username\": \"abc@gmail.com\",\"address\": \"!Earth\"}"

  val gson: Gson = new Gson()
  val extractedJson: User = gson.fromJson(jsonString, classOf[User])
  println(s"user is: ${extractedJson}")
}

case class User(username: String, address: String)

以上代码因以下异常而失败：

result: "{\"username\": \"abc@gmail.com\",\"address\": \"!Earth\"}"
Exception in thread "main" com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 2 path $
    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:226)
    at com.google.gson.Gson.fromJson(Gson.java:927)
    at com.google.gson.Gson.fromJson(Gson.java:892)
    at com.google.gson.Gson.fromJson(Gson.java:841)
    at com.google.gson.Gson.fromJson(Gson.java:813)
    at DecryptQRData$.delayedEndpoint$DecryptQRData$1(DecryptQRData.scala:15)
    at DecryptQRData$delayedInit$body.apply(DecryptQRData.scala:3)
    at scala.Function0.apply$mcV$sp(Function0.scala:39)
    at scala.Function0.apply$mcV$sp$(Function0.scala:39)
    at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:17)
    at scala.App.$anonfun$main$1$adapted(App.scala:80)
    at scala.collection.immutable.List.foreach(List.scala:392)
    at scala.App.main(App.scala:80)
    at scala.App.main$(App.scala:78)
    at DecryptQRData$.main(DecryptQRData.scala:3)
    at DecryptQRData.main(DecryptQRData.scala)
Caused by: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 2 path $
    at com.google.gson.stream.JsonReader.beginObject(JsonReader.java:385)
    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:215)
    ... 15 more

Process finished with exit code 1

但是当我更换

val jsonString: String = new String(finalData)
//jsonString contains "{\"username\": \"abc@gmail.com\",\"address\": \"!Earth\"}"

with
val jsonString: String = "{\"username\": \"abc@gmail.com\",\"address\": \"!Earth\"}"，我的程序正常工作，并显示User。

问题：当两个jsonString包含相同数据时，为什么用实际数据替换val jsonString: String = new String(finalData) println(s"jsonString: $jsonString") val removedQuotes = jsonString.replaceAll("^\"|\"$", "") println(s"removedQuotes: ${removedQuotes}") val gson: Gson = new Gson() val extractedJson: User = gson.fromJson(removedQuotes, classOf[User]) println(s"user is: ${extractedJson}") 有用。

编辑1：我尝试了以下代码（在开头和结尾都删除了引号）

jsonString: "{\"username\": \"abc@gmail.com\",\"address\": \"!Earth\"}"
removedQuotes: {\"username\": \"abc@gmail.com\",\"address\": \"!Earth\"}
Exception in thread "main" com.google.gson.JsonSyntaxException: com.google.gson.stream.MalformedJsonException: Expected name at line 1 column 2 path $.

但是，它也失败，并显示以下错误：

update (RENTAL_DATE +14) where RENTAL_DATE between '01-JAN-17' and '12-DEC-18'from MRE_COMP_DATA;

Answer 1

这是因为您的JSON负载看起来像：

"{"username": "abc@gmail.com","address": "!Earth"}

请注意"。当您首先删除"时，它将开始工作。请注意以下几行：

System.out.println("\"{}\"");
System.out.println("{}");

打印：

"{}"
{}

编辑

System.out.println("Start point: " + json);
json = json.substring(1, json.length() - 1);
System.out.println("Get without \": " + json);
json = json.replaceAll("\\\\\"", "\"");
System.out.println("Valid: " + json);

Gson gson = new Gson();
User user = gson.fromJson(json, User.class);

System.out.println(user);

上面的代码显示：

Start point: "{\"username\": \"abc@gmail.com\",\"address\": \"!Earth\"}"
Get without ": {\"username\": \"abc@gmail.com\",\"address\": \"!Earth\"}
Valid: {"username": "abc@gmail.com","address": "!Earth"}
User{username='abc@gmail.com', address='!Earth'}

另请参阅：

• “Expected BEGIN_OBJECT but was STRING at line 1 column 1”