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Last active Jul 26, 2016
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Using org.json in MATLAB
% download JSON.net from https://github.com/JamesNK/Newtonsoft.Json/releases
% extract into MATLAB folder
%% add assembly (assuming not registered in GAC)
asm = NET.addAssembly('%HOME%\Documents\MATLAB\Json70r1\bin\Net35\Newtonsoft.Json.dll')
%% DESERIALIZING JSON OBJECT
% using the following example:
% {"inputs":
% {"module":
% {"name": "spr-e20-435",
% "nameplate": 435
% }
% },
% {"request":
% {"startdate": [2015,1,1,1,0,0],
% "enddate": [2015,12,31,23,0,0]
% }
% }
% }
%% get source using io
str_data = fileread('path/to/file.json')
%% use Json.Convrters.DeserializeObject(str_data)
json_data = Newtonsoft.Json.JsonConvert.DeserializeObject(str_data)
inputs = json_data.GetValue('inputs')
module = inputs.GetValue('module')
name = module.GetValue('name').Value()
nameplate = module.GetValue('nameplate').Value()
startdate(1) = inputs.GetValue('request').Item(0)
startdate(2) = inputs.GetValue('request').Item(1)
startdate(3) = inputs.GetValue('request').Item(2)
startdate(4) = inputs.GetValue('request').Item(3)
startdate(5) = inputs.GetValue('request').Item(4)
startdate(6) = inputs.GetValue('request').Item(5)
%% prettyprint output
json_data.ToString()
%% SERIALIZE LINQ JSON OBJECT
% create a LINQ JObject
json_obj = Newtonsoft.Json.Linq.JObject() % create object
methodsview(json_obj) % view all methods for JObject
json_obj.Add('this', Newtonsoft.Json.Linq.JValue('that'))
json_obj.Add('foo', Newtonsoft.Json.Linq.JArray([10,20,30]))
json_obj.Add('bar', Newtonsoft.Json.Linq.JArray({'x','y','z'}))
%% prettyprint
json_obj.ToString() % pretty print
%% serialize json object
json_str = json_obj.Add('foo', Newtonsoft.Json.Linq.JArray([10,20,30]))
fid = fopen('outputfile.json')
fwrite(fid,json_str)
fclose(fid)
%% this is MATLAB, not Objective-C
%% orgJSONdemo.m
% a demo of org.json classes used in MATLAB
% NOTE: JSON.org must be on the Java classpath
%% clear workspace
clc
clear java % clear all and any java classes loaded from the dynamic path
clear import % clear all java imports
%% what version of Java JRE/JDK
version -java % display Java version (1.6 is Java Standard Edition 6)
%% simplify Java class names
import org.json.* % import all org.json classes
import java.util.HashMap % import a single class
import java.util.ArrayList % Maps and Collections are Java objects useful for JSONObjects and JSONArrays
% http://docs.oracle.com/javase/6/docs/api/java/util/Collection.html
% http://docs.oracle.com/javase/6/docs/api/java/util/Map.html
import % display imports
%% display JSONObject methods
methods JSONObject % list methods in command window
methodsview JSONObject % window with table of methods with return type, arguments and other info
methodsview('JSONArray') % to use as function call pass a string, NOT the object constructor!
% http://www.mathworks.com/help/techdoc/matlab_prog/f10-60037.html#f10-60072
methodsview HashMap
methodsview ArrayList
%% JSONObject - constructor methods
% public JSONObject()
% Construct an empty JSONObject.
% http://www.json.org/javadoc/org/json/JSONObject.html#JSONObject()
jo = JSONObject;jo.toString % () not required for no-arg function calls
% public JSONObject(java.lang.String source)
% Construct a JSONObject from a source JSON text string.
% http://www.json.org/javadoc/org/json/JSONObject.html#JSONObject(java.lang.String)
source = ['{module:SunPower SPR-315-WHT-AR D,', ... use braces, {}, but quotes, "", are not necessary, spaces OK
'Voc:0.6732,', ... numbers, strings & objects are interpreted automatically, use quotes to force numbers to string, e.g. "1"
'nothing:[],', ... an empty key value is NOT OK, but empty JSONArray is OK
'blah:null,', ... a json null key value is OK, so is an empty string, which is not the same as json null
'cells:[null,TRUE,False,', ... json null, true, false are OK, case insensitive
',"",', ... an emtpy Array element is a json null, "" is an empty string, which is not the same as json null
'"c:\\Program Files","\"in quotes\"",', ... use quotes, "\\", with an characters that need to be escaped, e.g. " or \
'"http://json.org"]}']; % use quotes for forward slash, /
jo = JSONObject(source);jo.toString(4) % display with 4-space indent
% public JSONObject(JSONObject jo, java.lang.String[] names)
% Construct a JSONObject from a subset of another JSONObject.
% http://www.json.org/javadoc/org/json/JSONObject.html#JSONObject(org.json.JSONObject, java.lang.String[])
jo = JSONObject(jo,{'module','Voc'});jo.toString(2) % cellstring is interpreted as array of strings
% public JSONObject(java.util.Map map)
% Construct a JSONObject from a Map.
% http://www.json.org/javadoc/org/json/JSONObject.html#JSONObject(java.util.Map)
clear jo
s = struct('module',{'SunPower SPR-315-WHT-AR D','SunPower SPR-240-WHT-AR D'}, ...
'Voc',{0.6732,0.7324}, ...
'cells',{1:3,[5,6;7,8]'});
map(size(s)) = HashMap; % create a Java array of objects of empty Hash-Maps
jo(size(s)) = JSONObject; % Java arrays must have consistent signature, emtpy constructor is OK
skeys = fieldnames(s); % keys are fieldnames
sVals = struct2cell(s); % values of fields in a cell array
for n = 1:size(s,2) % loop over rows
for m = 1:size(s,1) % loop over columns
for p = 1:length(skeys) % loop over keys (structure fields)
map(n,m).put(skeys{p},sVals{p,m,n}); % map each key to its value
end
jo(n,m) = JSONObject(map(n,m));jo(n,m).toString(3) % create json object from java hash map
end
end
%% JSONObject - PUT method
% public JSONObject put(java.lang.String key, java.lang.Object value)
% Put a key/value pair in the JSONObject.
% value - An object which is the value. It should be of one of these types:
% Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONObject.NULL object.
% http://www.json.org/javadoc/org/json/JSONObject.html#put(java.lang.String, java.lang.Object)
clear jo
s = struct('module',{'SunPower SPR-315-WHT-AR D','SunPower SPR-240-WHT-AR D'}, ...
'Voc',{0.6732,0.7324}, ...
'cells',{1:3,[5,6;7,8]'});
jo(size(s)) = JSONObject; % Java arrays must have consistent signature, emtpy constructor is OK
skeys = fieldnames(s); % keys are fieldnames
sVals = struct2cell(s); % values of fields in a cell array
for n = 1:size(s,2) % loop over rows
for m = 1:size(s,1) % loop over columns
for p = 1:length(skeys) % loop over keys (structure fields)
jo(n,m).put(skeys{p},sVals{p,m,n}); % map each key to its value
end
jo(n,m).toString(5)
end
end
jo(1,1).put('module',{}) % remove that key form the json object
jo(1,1).put('module',[]) % put an emtpy json array
jo(1,1).put('module',[{}]) %#ok<NBRAK> % remove that key form the json object
jo(1,1).put('module','') % put an emtpy json array
jo(1,1).put('module',{[]}) % put a java object array with a single empty MATLAB array
jo(1,1).put('module',{''}) % put a java string array with a single empty java string
%% JSONObject - QUOTE method
% public static java.lang.String quote(java.lang.String string)
% Produce a string in double quotes with backslash sequences in all the right places. A backslash will be inserted within
% http://www.json.org/javadoc/org/json/JSONObject.html#quote(java.lang.String)
srcVal(1) = JSONObject.quote('C:\Program Files'); % use quote to check if a string needs to be altered to be json source text
srcVal(2) = JSONObject.quote('http://org.json');disp(srcVal) % quote returns a Java string
jo = JSONObject(['{file:',char(srcVal(1)),',url:',char(srcVal(2)),'}']);jo.toString(1) % use char to convert Java string to
%% JSONObject - GET, GET<TYPE> method
% public java.lang.Object get(java.lang.String key)
% Get the value object associated with a key.
% http://www.json.org/javadoc/org/json/JSONObject.html#get(java.lang.String)
jo = JSONObject('{module:[SunPower SPR-240-WHT-AR D,SunPower SPR-315-WHT-AR D],gen:[B50,C60]}');jo.toString(4)
modJA = jo.get('module');modJA.get(0),modJA.get(1) % matlab arrays index from 1, java arrays index from 0
genJA = jo.getJSONArray('gen'); % using getJSONArray will throw an error if value of key is not a JSONArray
%% et cetera - I think you get the idea.
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