Convert a JSON string to object in Java ME

Question

Is there a way in Java J2ME to convert a string  such as    name  MyNode   width 200  height 100    to an internal Object representation of the same  in one line of code    Because the current method is too tedious   Object n   create  new    setString p   name    MyNode    setInteger p   width   200   setInteger p   height   100     Maybe a JSON library

User · Answer

This is an old question and json-simple (https://code.google.com/p/json-simple/) could be a good solution at that time, but please consider that project seems not to be active for a while !

I suggest the Gson which is now hosted at: https://github.com/google/gson

If performance is your issue you can have a look at some benchmarks http://blog.takipi.com/the-ultimate-json-library-json-simple-vs-gson-vs-jackson-vs-json/ which compare.

User · Answer

You can do this easily with Google GSON   Let s say you have a class called User with the fields user  width  and height and you want to convert the following json string to the User object     name   MyNode    width  200   height  100   You can easily do so  without having to cast  keeping nimcap s comment in mind       with the following code   Gson gson   new Gson     final User user   gson fromJson jsonString  User class     Where jsonString is the above JSON String   For more information  please look into https   code google com p google-gson

User · Answer

Use google GSON library for this  public static  lt T gt  T getObject final String jsonString  final Class lt T gt  objectClass          Gson gson   new Gson          return gson fromJson jsonString  objectClass         http   iandjava blogspot in 2014 01 java-object-to-json-and-json-to-java html

User · Answer

Apart from www json org you can also implement your own parser using javacc and matching your personnal grammar schema  See this note on my blog   http   plindenbaum blogspot com 2008 07 parsing-json-with-javacc-my-notebook html

User · Answer

JSON IO is by far the easiest way to convert a JSON string or JSON input stream to a Java Object  String to Java Object Object obj   JsonReader jsonToJava     Hello  World        https   code google com p json-io

User · Answer

Like many stated already  A pretty simple way to do this using JSON simple as below  import org json JSONObject   String someJsonString     name  MyNode   width 200  height 100    JSONObject jsonObj   new JSONObject someJsonString     And then use jsonObj to deal with JSON Object  e g jsonObj get  name     As per the below link  JSON simple is showing constant efficiency for both small and large JSON files  http   blog takipi com the-ultimate-json-library-json-simple-vs-gson-vs-jackson-vs-json

User · Answer

The simplest option is Jackson   MyObject ob   new ObjectMapper   readValue jsonString  MyObject class     There are other similarly simple to use libraries  Gson was already mentioned   but some choices are more laborious  like original org json library  which requires you to create intermediate  JSONObject  even if you have no need for those

User · Answer

I ve written a library that uses json org to parse JSON  but it will actually create a proxy of an interface for you  The code JAR is on code google com   http   fixjures googlecode com   I don t know if it works on J2ME  Since it uses Java Reflection to create proxies  I m thinking it won t work  Also  it s currently got a hard dependency on Google Collections which I want to remove and it s probably too heavyweight for your needs  but it allows you to interact with your JSON data in the way you re looking for   interface Foo       String getName        int getWidth        int getHeight       Foo myFoo   Fixjure of Foo class  from JSONSource newJsonString    name     foo name        create    String name   myFoo getName       name now  equals  foo name

User · Answer

Jackson for big files  GSON for small files  and JSON simple for handling both

User · Answer

JSON official site is where you should look at  It provides various libraries which can be used with Java  I ve personally used this one  JSON-lib which is an implementation of the work in the site  so it has exactly the same class - methods etc in this page    If you click the html links there you can find anything you want    In short    to create a json object and a json array  the code is    JSONObject obj   new JSONObject    obj put  variable1   o1   obj put  variable2   o2   JSONArray array   new JSONArray    array put obj     o1  o2  can be primitive types  long  int  boolean   Strings or Arrays    The reverse process is fairly simple  I mean converting a string to json object array    String myString   JSONObject obj   new JSONObject myString    JSONArray array   new JSONArray myString     In order to be correctly parsed you just have to know if you are parsing an array or an object

User · Answer

You have many JSON parsers for Java    JSONObject java A JSONObject is an unordered collection of name value pairs  Its external form is a string wrapped in curly braces with colons between the names and values  and commas between the values and names  The internal form is an object having get    and opt   methods for accessing the values by name  and put   methods for adding or replacing values by name  The values can be any of these types  Boolean  JSONArray  JSONObject  Number  and String  or the JSONObject NULL object  JSONArray java A JSONArray is an ordered sequence of values  Its external form is a string wrapped in square brackets with commas between the values  The internal form is an object having get   and opt   methods for accessing the values by index  and put   methods for adding or replacing values  The values can be any of these types  Boolean  JSONArray  JSONObject  Number  and String  or the JSONObject NULL object  JSONStringer java A JSONStringer is a tool for rapidly producing JSON text  JSONWriter java A JSONWriter is a tool for rapidly writing JSON text to streams  JSONTokener java A JSONTokener takes a source string and extracts characters and tokens from it  It is used by the JSONObject and JSONArray constructors to parse JSON source strings  JSONException java A JSONException is thrown when a syntax or procedural error is detected  JSONString java The JSONString is an interface that allows classes to implement their JSON serialization

User · Answer

GSON is a good option to convert java object to json object and vise versa  It is a tool provided by google   for converting json to java object use  fromJson jsonObject javaclassname class  for converting java object to json object use  toJson javaObject  and rest will be done automatically  For more information and for download

User · Answer

Just make a Json object in java with the following Json String In your case    name  MyNode   width 200  height 100    if the above is your Json string   just create a Json Object with it   JsonString    name  MyNode   width 200  height 100    JSONObject yourJsonObject   new JSONObject JsonString   System out println  name     yourJsonObject getString  name     System out println  width     yourJsonObject getString  width

User · Answer

I used a few of them and my favorite is   http   code google com p json-simple   The library is very small so it s perfect for J2ME    You can parse JSON into Java object in one line like this   JSONObject json    JSONObject new JSONParser   parse     name     MyNode      width   200    height   100     System out println  name     json get  name     System out println  width     json get  width

[java] Convert a JSON string to object in Java ME?

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