Generally speaking when you serialize/deserialize an object, you are doing so to end up with an exact copy of the state of the object; As such, you generally want to circumvent the encapsulation normally desired in an OO design.  If you do not circumvent the encapsulation, it may not be possible to end up with an object that has the exact same state after deserialization as it had prior to serialization.  Additionally, consider the case where you do not want to provide a setter for a particular property.  How should serialization/deserialization act if you are working through the getters and setters?

&gt; Is there a way to tell GSON to use only getters and setters?

Not yet.

From [the design doc][1]:

&gt;[T]here are good arguments to support properties as well. We intend to enhance Gson in a latter version to support properties as an alternate mapping for indicating Json fields. For now, Gson is fields-based. 


  [1]: https://github.com/google/gson/blob/master/GsonDesignDocument.md

It is possible to to patch Gson to [use getters][1].


  [1]: https://github.com/google/gson/issues/232

The vague outline of how this works in our app is that we have a lot of `TypeAdapter` implementations - some for specific value-like objects and some for bean-style objects where we know that JavaBeans logic will work. We then jam all of these onto a `GsonBuilder` before creating the `Gson` object.

Unfortunately, GSON is really crap at handling types like `Object[]`. We mostly saw this when we were trying to make a JSON object to represent method parameters. The workaround for that was to make custom `TypeAdapter` instances which reflect the methods. (This does mean that you end up using one `Gson` instance per method you intend to call...)

I have IDs that look like: __185-51-671__ but they can also have letters at the end, __175-1-7b__ 

All I want to do is remove the hyphens, as a pre-processing step.  Show me some cool ways to do this in javascript?  I figure there are probably quite a few questions like this one, but I&#39;m interested to see what optimizations people will come up with for &quot;just hyphens&quot;

Thanks!


edit: I am using jQuery, so I guess .replace(a,b) does the trick (replacing a with b)


    numberNoHyphens = number.replace(&quot;-&quot;,&quot;&quot;);

any other alternatives?


edit #2:

So, just in case anyone is wondering, the correct answer was 

    numberNoHyphens = number.replace(/-/g,&quot;&quot;);

and you need the &quot;g&quot; which is the pattern switch or &quot;global flag&quot; because

    numberNoHyphens = number.replace(/-/,&quot;&quot;);
will only match and replace the first hyphen

Fastest way to remove hyphens from a string

I am trying to create a generic method for object updates using scala / java but I can&#39;t get the class for a type parameter.

Here is my code:

    object WorkUnitController extends Controller {     
     def updateObject[T](toUpdate: T, body: JsonObject){
      val source = gson.fromJson(body, classOf[T]);
      ...
     }
    }

The error i get is 

&gt; class type required but T found

I know in java you can&#39;t do it but is this possible in scala at all?

Thanks!


Scala classOf for type parameter

Why does GSON use **ONLY** fields(private,public,protected)?
Is there a way to tell GSON to use only getters and setters?



Why does GSON use fields and not getters/setters?

<p>Why does GSON use <strong>ONLY</strong> fields(private,public,protected)?
Is there a way to tell GSON to use only getters and setters?</p>


I&#39;m running a webapp in Spring Web MVC 3.0 and I have a number of controller methods whose signatures are roughly as follows:

    @RequestMapping(value = &quot;/{level1}/{level2}/foo&quot;, method = RequestMethod.POST)
    public ModelAndView createFoo(@PathVariable long level1,
            @PathVariable long level2,
            @RequestParam(&quot;foo_name&quot;) String fooname,
            @RequestParam(value = &quot;description&quot;, required = false) String description);


I&#39;d like to add some validation - for example, `description` should be limited to a certain length or `fooname` should only contain certain characters. If this validation fails, I want to return a message to the user rather than just throw some unchecked exception (which would happen anyway if I let the data percolate down to the DAO layer). I&#39;m aware of JSR303 but have not worked with it and don&#39;t quite understand how to apply it in a Spring context.

From what I understand, another option would be to bind the `@RequestBody` to an entire domain object and add validation constraints there, but currently my code is set up to accept individual parameters as shown above.

What is the most straightforward way to apply validation to input parameters using this approach?

Spring Web MVC - validate individual request params

This is what I can do in JUnit:

    import org.junit.*;
    @Ignore
    public class FooTest {
      //
    }

and the entire class will be ignored. How can I do the same in TestNG?

How to disable entire unit test in TestNG?

When we must use a `_` to separate digits in a number I don&#39;t understand the following case in which I can&#39;t use it:

&gt;In positions where a string of digits is expected

(as documented in the JDK7 guide [here][1])

Some examples?

[1]: https://docs.oracle.com/javase/7/docs/technotes/guides/language/underscores-literals.html


Java 7 underscore in numeric literals

I&#39;m loading properties attributes from a `.properties` file using Spring as follows:

    file: elements.properties
    base.module.elementToSearch=1
    base.module.elementToSearch=2
    base.module.elementToSearch=3
    base.module.elementToSearch=4
    base.module.elementToSearch=5
    base.module.elementToSearch=6

The spring xml file

    file: myapplication.xml
    &lt;bean id=&quot;some&quot;
          class=&quot;com.some.Class&quot;&gt;
          &lt;property name=&quot;property&quot; value=&quot;#{base.module.elementToSearch}&quot; /&gt;
    &lt;/bean&gt;

And my Class.java

    file: Class.java
    public void setProperty(final List&lt;Integer&gt; elements){
        this.elements = elements;
    }

But when debugging, the parameter elements only get the last element into the list, so, there is a list of one element with value &quot;6&quot;, instead of a list with 6 elements.

I tried other approaches, like adding in value only `#{base.module}` but then it finds no parameter in the properties file.

A workaround is to have in elements.properties file a list separated by commas, like:

    base.module.elementToSearch=1,2,3,4,5,6

and use it as a String and parse it, but is there a better solution?

Spring .properties file: get element as an Array

Method to copy entire directory contents to another directory in java or groovy?

Copy entire directory contents to another directory?

I&#39;m trying to have a custom date format in Gson output, but `.setDateFormat(DateFormat.FULL)` doesn&#39;t seem to work and it the same with `.registerTypeAdapter(Date.class, new DateSerializer())`.

It&#39;s like Gson doesn&#39;t care about the object &quot;Date&quot; and print it in its way.

How can I change that?

Thanks

EDIT: 

    @Entity
    public class AdviceSheet {
      public Date lastModif;
    [...]
    }

    public void method {
       Gson gson = new GsonBuilder().setDateFormat(DateFormat.LONG).create();
       System.out.println(gson.toJson(adviceSheet);
    }

I always use `java.util.Date`; `setDateFormat()` doesn&#39;t work :(




GSON - Date format

I&#39;ve got the following classes

    public class MyClass {
        private List&lt;MyOtherClass&gt; others;
    }
    
    public class MyOtherClass {
        private String name;
    }

And I have JSON that may look like this

    {
      others: {
        name: &quot;val&quot;
      }
    }

or this

    {
      others: [
        {
          name: &quot;val&quot;
        },
        {
          name: &quot;val&quot;
        }
      ]
    }

I&#39;d like to be able to use the same `MyClass` for both of these JSON formats. Is there a way to do this with Gson?




Gson handle object or array

I&#39;m getting a date/time in json as `2011-10-26T20:29:59-07:00`. What&#39;s the proper way to use `gsonBuilder.setDateFormat` to properly format this time? 

GsonBuilder setDateFormat for &quot;2011-10-26T20:29:59-07:00&quot;

This is related to a previous question that I asked here earlier

https://stackoverflow.com/questions/8207274/json-parsing-using-gson/8207343#8207343

I am trying to parse the same JSON, but now I have changed my classes a little bit.

    {
        &quot;lower&quot;: 20,
        &quot;upper&quot;: 40,
        &quot;delimiter&quot;: &quot; &quot;,
        &quot;scope&quot;: [&quot;${title}&quot;]
    }

My class now looks like:

    public class TruncateElement {

       private int lower;
       private int upper;
       private String delimiter;
       private List&lt;AttributeScope&gt; scope;

       // getters and setters
    }


    public enum AttributeScope {

	    TITLE(&quot;${title}&quot;),
	    DESCRIPTION(&quot;${description}&quot;),

	    private String scope;

	    AttributeScope(String scope) {
			this.scope = scope;
		}

		public String getScope() {
			return this.scope;
		}
    }


This code throws an exception, 

    com.google.gson.JsonParseException: The JsonDeserializer EnumTypeAdapter failed to deserialized json object &quot;${title}&quot; given the type class com.amazon.seo.attribute.template.parse.data.AttributeScope
	at 

The exception is understandable, because as per the solution to my previous question, GSON is expecting the Enum objects to be actually be created as  

    ${title}(&quot;${title}&quot;),
    ${description}(&quot;${description}&quot;);

But since this is syntactically impossible, what are the recommended solutions, workarounds?





Using Enums while parsing JSON with GSON

[This][1] link from the Gson project seems to indicate that I would have to do something like the following for serializing a typed Map to JSON:


        public static class NumberTypeAdapter 
          implements JsonSerializer&lt;Number&gt;, JsonDeserializer&lt;Number&gt;,
    InstanceCreator&lt;Number&gt; {
    
        public JsonElement serialize(Number src, Type typeOfSrc, JsonSerializationContext
    context) {
          return new JsonPrimitive(src);
        }
    
        public Number deserialize(JsonElement json, Type typeOfT,
    JsonDeserializationContext context)
            throws JsonParseException {
          JsonPrimitive jsonPrimitive = json.getAsJsonPrimitive();
          if (jsonPrimitive.isNumber()) {
            return jsonPrimitive.getAsNumber();
          } else {
            throw new IllegalStateException(&quot;Expected a number field, but was &quot; + json);
          }
        }
    
        public Number createInstance(Type type) {
          return 1L;
        }
      }
    
      public static void main(String[] args) {
        Map&lt;String, Number&gt; map = new HashMap&lt;String, Number&gt;();    
        map.put(&quot;int&quot;, 123);
        map.put(&quot;long&quot;, 1234567890123456789L);
        map.put(&quot;double&quot;, 1234.5678D);
        map.put(&quot;float&quot;, 1.2345F);
        Type mapType = new TypeToken&lt;Map&lt;String, Number&gt;&gt;() {}.getType();
    
        Gson gson = new GsonBuilder().registerTypeAdapter(Number.class, new
    NumberTypeAdapter()).create();
        String json = gson.toJson(map, mapType);
        System.out.println(json);
        
        Map&lt;String, Number&gt; deserializedMap = gson.fromJson(json, mapType);
        System.out.println(deserializedMap);
      }

Cool and that works, but it seems like so much overhead (***a whole Type Adapter class?***). I have used other JSON libraries like JSONLib and they let you build a map in the following way:



    JSONObject json = new JSONObject();
    for(Entry&lt;String,Integer&gt; entry : map.entrySet()){
         json.put(entry.getKey(), entry.getValue());
    }

Or if I have a custom class something like the following:

    JSONObject json = new JSONObject();
    for(Entry&lt;String,MyClass&gt; entry : map.entrySet()){
	 JSONObject myClassJson =  JSONObject.fromObject(entry.getValue());
         json.put(entry.getKey(), myClassJson);
    }


The process is more manual, but requires way less code and doesn&#39;t have the overhead of haivng to create a custom Type Adapter for Number or in most cases ***for my own custom class***.


Is this the only way to serialize a map with Gson, or has anyone found a way that beats out what Gson recommends in the link above.


  [1]: http://code.google.com/p/google-gson/issues/detail?id=45


Content Type	Original Author	Original Content on Stackoverflow
Question	Zemzela	View Question on Stackoverflow
Solution 1 - Java	Chris Shaffer	View Answer on Stackoverflow
Solution 2 - Java	Programmer Bruce	View Answer on Stackoverflow
Solution 3 - Java	Jimmy	View Answer on Stackoverflow
Solution 4 - Java	Hakanai	View Answer on Stackoverflow

Why does GSON use fields and not getters/setters?

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Scala classOf for type parameter

Fastest way to remove hyphens from a string

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