Decoding JSON String in Java

Question

I am new to using the json-simple library in Java and I ve been through both the encoding and decoding samples  Duplicating the encoding examples was fine  but I have not been able to get the decoding ones to work with mixed type JSON   One of my problems is that there are too many classes in the library which are not properly documented  and for which I do not have the source  in order to be able to read through and understand their purpose   Consequently  I am struggling to understand how to use a lot of these classes   After reading this example   String jsonText       first    123    second     4  5  6     third    789    JSONParser parser   new JSONParser     ContainerFactory containerFactory   new ContainerFactory        public List creatArrayContainer             return new LinkedList               public Map createObjectContainer             return new LinkedHashMap                                   try       Map json    Map parser parse jsonText  containerFactory       Iterator iter   json entrySet   iterator        System out println    iterate result           while iter hasNext              Map Entry entry    Map Entry iter next            System out println entry getKey        gt     entry getValue                System out println    toJSONString            System out println JSONValue toJSONString json      catch ParseException pe        System out println pe       from the json-simple official decoding tutorial  I tried to decode this JSON      stat         sdr    MAC address of FLYPORT        rcv    ff ff ff ff ff ff        time    0000000000000        type   0       subt   0       argv               type    6   val    NetbiosName              type    6   val    MACaddrFlyport              type    6   val    FlyportModel              type    1   val   id              I am writing following code to decode       String jsonString       stat      sdr      aa bb cc dd ee ff     rcv      aa bb cc dd ee ff     time      UTC in millis     type    1   subt    1   argv      1 2   2 3           JSONObject jsonObject   new JSONObject jsonString       JSONObject newJSON   jsonObject getJSONObject  stat        System out println newJSON     But it doesn t work  Infact I was not able to get the unmodified example working either  and the original authors have not explained their code   What is the easiest way to decode this JSON as shown

User · Accepted Answer

This is the best and easiest code   public class test       public static void main String str                  String jsonString       stat        sdr      aa bb cc dd ee ff      rcv      aa bb cc dd ee ff      time      UTC in millis      type    1    subt    1    argv        type    1    val     stackoverflow                 JSONObject jsonObject   new JSONObject jsonString           JSONObject newJSON   jsonObject getJSONObject  stat            System out println newJSON toString             jsonObject   new JSONObject newJSON toString             System out println jsonObject getString  rcv            System out println jsonObject getJSONArray  argv               The library definition of the json files are given here  And it is not same libraries as posted here  i e  posted by you  What you had posted was simple json library I have used this library   You can download the zip  And then create a package in your project with org json as name  and paste all the downloaded codes there  and have fun   I feel this to be the best and the most easiest JSON Decoding

User · Answer

Instead of downloading separate java files as suggested by Veer  you could just add this JAR file to your package   To add the jar file to your project in Eclipse  do the following    Right click on your project  click Build Path   Configure Build Path Goto Libraries tab   Add External JARs Locate the JAR file and add

User · Answer

This is the JSON String we want to decode           stats              sdr    aa bb cc dd ee ff            rcv    aa bb cc dd ee ff            time    UTC in millis            type   1           subt   1           argv                 1   2                2   3                I store this string under the variable name  sJSON  Now  this is how to decode it        Creating a JSONObject from a String  JSONObject nodeRoot    new JSONObject sJSON        Creating a sub-JSONObject from another JSONObject JSONObject nodeStats   nodeRoot getJSONObject  stats        Getting the value of a attribute in a JSONObject String sSDR   nodeStats getString  sdr

User · Answer

Well your jsonString is wrong    String jsonString       stat      sdr      aa bb cc dd ee ff     rcv      aa bb cc dd ee ff     time      UTC in millis     type    1   subt    1   argv        1   2     2   3         use this jsonString and if you use the same JSONParser and ContainerFactory in the example you will see that it will be encoded decoded   Additionally if you want to print your string after stat here it goes        try          Map json    Map parser parse jsonString  containerFactory           Iterator iter   json entrySet   iterator            System out println    iterate result              Object entry   json get  stat            System out println entry             And about the json libraries  there are a lot of them  Better you check this

[java] Decoding JSON String in Java

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