org.json.JSONException: A JSONArray text must start with '['

Question

I have the following json file:

[   { "1" : "b1.png"},
    { "2" : "bb1.png"},
    { "3" : "bbg1.png"}
]

and in the following line:

JSONArray array = new JSONArray(jsonFilePath);

I get the following exception:

org.json.JSONException: A JSONArray text must start with '[' at 1 [character 2 line 1]
    at org.json.JSONTokener.syntaxError(JSONTokener.java:433)
    at org.json.JSONArray.<init>(JSONArray.java:105)
    at org.json.JSONArray.<init>(JSONArray.java:144)
    at il.ac.technion.cs234311.dolphins.parse.ParseCardsTest.initialize(ParseCardsTest.java:23)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

But it is start with '[' !!!

Any ideas? Thanks a lot!

Is jsonFilePath the path to the file? It should be the JSON string. — Jared Rummler, Dec 17 '14 at 03:04
Yes, it is the path to the file.. I need to get the JsonObject first, and only than convert it to a jsonArray? — user2320431, Dec 17 '14 at 03:06
jsonFilePath(It must be String of JSON) can be null. Print it out before calling JSONArray to see it. — Semih Eker, Dec 17 '14 at 03:06

August · Answer 1 · 2014-12-17T03:23:01.810

3

Create a JSONTokener:

Reader in = new InputStreamReader(new FileInputStream(jsonFilePath), StandardCharsets.UTF_8);
JSONArray array = new JSONArray(new JSONTokener(in));
in.close();

You'll need to handle FileNotFoundException as well.

edited Dec 17 '14 at 03:23

answered Dec 17 '14 at 03:11

August

12,410
3
35
51

1

Does JSONTokener close the input stream? If not you'll need to take care of that yourself. Also, watch out for charset issues with FileReader. It always uses the platform default encoding, which might not be compatible with UTF-8. See http://stackoverflow.com/a/696641/611819 – dnault Dec 17 '14 at 03:14

score 3 · Accepted Answer · answered Dec 17 '14 at 03:12

As @JaredRummler suggested, you need to read the contents of the file into a String first, and then pass that String to the JSONArray constructor. Here's some sample code that uses Apache Commons IO to read the file:

import org.apache.commons.io.IOUtils;

...

public static String readJsonFile(String filename) throws IOException {
    try (InputStream is = new FileInputStream(filename)) {
        return IOUtils.toString(is, StandardCharsets.UTF_8);
    }    
}

....

JSONArray array = new JSONArray(readJsonFile(jsonFilePath));

August's answer using JSONTokener is probably more efficient since it doesn't require reading the whole file into memory at once. — dnault, Dec 17 '14 at 03:17

org.json.JSONException: A JSONArray text must start with '['

2 Answers2

Linked