How to convert a JSON JString value to an ordinary String in Lift?

Question

Having a jString : JString value holding an "abc" string inside I get "JString(abc)" : String if I call jString.toString. How do I get "abc" : String instead?

I've found the solution to use `jString.values : String` but I feel uncertain if it's correct - why is it called `values` (not a `value`) if there's just a `String`? — Ivan, Oct 16 '11 at 03:19

score 19 · Answer 1 · edited May 23 '17 at 12:34

19

To extract a value from JValue you can use any method described here: What is the most straightforward way to parse JSON in Scala?

For instance:

json.extract[String]

You can use 'render' function to convert any JValue to printable format. Then either 'pretty' or 'compact' will convert that to a String.

compact(render(json))

or

pretty(render(json))

edited May 23 '17 at 12:34

Community

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answered Oct 16 '11 at 09:06

Joni

2,779
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I don't want to render JSON. I want the opposite - to extract a string value of a property of an object serialized in JSON and I've already isolated that only field into a separate JString, containing nothing but the value I need. – Ivan Oct 16 '11 at 09:18

score 7 · Answer 2 · answered Jun 12 '12 at 00:34

7

I believe the best way is to use match:

val x = ... (whatever, maybe it's a JString)

x match {
  case JString(s) => do something with s
  case _          => oops, something went wrong
}

answered Jun 12 '12 at 00:34

Vlad Patryshev

1,379
1
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score 7 · Answer 3 · answered Mar 27 '12 at 00:08

7

val jstring=JString("abc")
implicit val formats = net.liftweb.json.DefaultFormats 
System.out.println(jstring.extract[String])

answered Mar 27 '12 at 00:08

Win Myo Htet

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score 1 · Answer 4 · answered Mar 10 '15 at 22:29

This was asked a while ago, but I wanted a simple one-line helper that would get my string for me in the context of an expression, so I wrote this little thing inside of an object called Get:

  object Get {
    def string(value: JValue): String = {                                                                                                               
      val JString(result) = value                                                                                            
      result                                                                                                                              
    }
  ...
  }

This way I can just do, e.g., val myString = Get.string(jsonStringValue)

How to convert a JSON JString value to an ordinary String in Lift?

4 Answers4