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POHow to deserialize JSON with GSON into corresponding generic Java types?
 

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    <p>I want to deserialize a JSON object (using GSON, because I already use it for searializing objects) to a general Map of type <code>Map&lt;String, Object&gt;</code>. It should create Objects of types that do correspond to the according JSON types, i.e. this JSON Object</p> <pre><code>{ "docID" : "a12345", "relation" : ["1", "2", "3"], "title" : { "de" : "German Title", "en" : "English Title"} } </code></pre> <p>should be deserialized in a <code>Map&lt;String, Object&gt;</code> with entries of the following types:<br> (<code>String</code>, <code>String</code>), (<code>String</code>, <code>List&lt;String&gt;</code>), (<code>String</code>, <code>Map&lt;String, String&gt;</code>).</p> <p>I tried to use the following code:</p> <pre><code>class Dictionary_ extends HashMap&lt;String, Object&gt; { // nothing to do }; private static final GsonBuilder GSON_BUILDER = new GsonBuilder(); public Map&lt;String, Object&gt; deserializeJsonString(String jsonString) { Dictionary_ d = new Dictionary(); return GSON_BUILDER.create().fromJson(jsonString, d.getClass()); } </code></pre> <p>But then the resulting types of created Objects are as follows:<br> (<code>String</code>, <code>Object</code>), (<code>String</code>, <code>Object</code>), (<code>String</code>, <code>Object</code>) and I am not able to cast these objects into the corresponding "real" types, because I get class cast exceptions.</p> <p>I am not able to use POJOs, since the data I am receiving does not have predefined structure in terms of class members.</p> <p>So, how am I able to deserialize such generic data in according generic Java types?</p> <p><strong>Update:</strong><br> I just tried to implement it using JSON Simple, and it works out of the box very easily by the following code:</p> <pre><code> Object ret = JSONValue.parse(jsonString); return (List&lt;Map&lt;String, Object&gt;&gt;) ret; </code></pre> <p>Why does it not work that easy with GSON???</p>
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