JSON string could not convert to array/ArrayList

Question

[
    {
        countryCode: "CN",
        countryCallingCode: "+86",
        codeRule: "^1\d{10}$"
    },
    {
        countryCode: "US",
        countryCallingCode: "+1",
        codeRule: "^\d{10}$"
    }
]

So I define the model like this in Kotlin

data class CountryCallingCode(
        val countryCode: String,
        val countryCallingCode: String,
        val codeRule: String? = null
)

This is what the backend document defines the response. codeRule is regex expression to verify a phone number.

I stuck in convert the String to List.

I pasted them to Android Studio, and it shows like:

String response = "[\n" +
        "    {\n" +
        "        countryCode: \"CN\",\n" +
        "        countryCallingCode: \"+86\",\n" +
        //"        codeRule: \"^1\\d{10}$\"\n" +
        "    },\n" +
        "    {\n" +
        "        countryCode: \"US\",\n" +
        "        countryCallingCode: \"+1\",\n" +
        //"        codeRule: \"^\\d{10}$\"\n" +
        "    }\n" +
        "]";

The following codes do not work.

Converting code 1:

Gson gson = new Gson()
CountryCallingCode[] countryCallingCodeList = gson.fromJson(response, CountryCallingCode[].class);

And I think the following codes are the same, correct me if I am wrong.

Converting code 2:

ArrayList<CountryCallingCode> countryCallingCodeList = (ArrayList<CountryCallingCode>)gson.fromJson(response, ArrayList.class);

Converting Code 3

Gson gson = new Gson();
        Type type = new TypeToken<List<CountryCallingCode>>() {
        }.getType();
        List<CountryCallingCode> countryCallingCodeList = gson.fromJson(response, type);

Then I use https://jsoneditoronline.org/ to reformat my json.

I tried to remove the codeRule, and pasted to the Android Studio, it also tells me I am wrong, it shows CountryCode causes SyntaxException.

    String reponse = "[\n" +
            "    {\n" +
            "        countryCode: \"CN\",\n" +
            "        countryCallingCode: \"+86\"\n" +
            "    },\n" +
            "    {\n" +
            "        countryCode: \"US\",\n" +
            "        countryCallingCode: \"+1\"\n" +
            "    }\n" +
            "]";

Only I compress the jsonstring to oneline, I could convert the jsonstring to the array/ArrayList.

String response = "[{\"countryCode\":\"CN\",\"countryCallingCode\":\"+86\"},{\"countryCode\":\"US\",\"countryCallingCode\":\"+1\"}]";

Does anyone know

Q1:

How to deal with codeRule?

Q2:

Why couldn't I pasted the origin JsonString to the Android Studio?

Why I must compress the JsonString into one line string?

Updated:

Origin one line json string:

[{"countryCode":"CN","countryCallingCode":"+86", codeRule: "^1\d{10}$"},{"countryCode":"US","countryCallingCode":"+1", codeRule: "^\d{10}$"}]

Pasted result json string:

String response = "[{\"countryCode\":\"CN\",\"countryCallingCode\":\"+86\", codeRule: \"^1\\d{10}$\"},{\"countryCode\":\"US\",\"countryCallingCode\":\"+1\", codeRule: \"^\\d{10}$\"}]";

Code:

Gson gson = new Gson();

/* Convertion 1 */
CountryCallingCode[] countryCallingCodeList = gson.fromJson(response, CountryCallingCode[].class);

Error:

result = {JsonSyntaxException@7237} Method threw 'com.google.gson.JsonSyntaxException' exception.
 cause = {MalformedJsonException@7241} "com.google.gson.stream.MalformedJsonException: Invalid escape sequence at line 1 column 65 path $[0].codeRule"
 detailMessage = "com.google.gson.stream.MalformedJsonException: Invalid escape sequence at line 1 column 65 path $[0].codeRule"
 stackState = null
 stackTrace = {StackTraceElement[28]@7243} 
 suppressedExceptions = {Collections$EmptyList@7244}  size = 0
 shadow$_klass_ = {Class@1694} "class com.google.gson.JsonSyntaxException"
 shadow$_monitor_ = -2082115852

A1: I believe its an issue with parsing regexes related A2: When pasting it directly, android studio added characters which should not be included in a json. It does that to keep the source formatting, which you actually don't want. The JSON format has no spaces and no \n, unless they are included in a string value — XtremeBaumer
– XtremeBaumer, Commented Jul 4, 2019 at 14:59
A completely valid JSON, wraps the field names in quotes as well: [ { "countryCode":"CN", "countryCallingCode":"+86", "codeRule":"^1\\d{10}$" } ] — XtremeBaumer
– XtremeBaumer, Commented Jul 4, 2019 at 15:05
I am not sure why you get codeRule without the quotes, but that is your issue left — XtremeBaumer
– XtremeBaumer, Commented Jul 4, 2019 at 15:11
@XtremeBaumer Thanks, I could run and get the list when the response is val response = "[{\"countryCode\":\"CN\",\"countryCallingCode\":\"+86\",\"codeRule\":\"^1\\\\d{10}$\"},{\"countryCode\":\"US\",\"countryCallingCode\":\"+1\",\"codeRule\":\"^\\\\d{10}$\"}]" — Francis Bacon
– Francis Bacon, Commented Jul 6, 2019 at 9:13

James Allen · Accepted Answer · 2019-07-04 17:06:12Z

0

This is more of a comment than an answer, but I need more space to explain - if your version of Java supports it, can you try creating your response with a raw string like this:

String response = `[
    {
        countryCode: "CN",
        countryCallingCode: "+86",
        codeRule: "^1\d{10}$"
    },
    {
        countryCode: "US",
        countryCallingCode: "+1",
        codeRule: "^\d{10}$"
    }
]`

Or if possible use Kotlin, which uses """ to delimit raw strings. It will be much more readable and might help you spot mistakes

answered Jul 4, 2019 at 17:06

James Allen

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2 Comments

Francis Bacon Over a year ago

How to create my response with a raw string like this?Do I need to type it manually?

Francis Bacon Over a year ago

' ' is not allowed for both Java and Kotlin, could you gave me a buildable codes?

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