Json <-> Java serialization that works with GWT [closed]

Take a look at GWT's Overlay Types. I think this is by far the easiest way to work with JSON in GWT. Here's a modified code example from the linked article:

public class Customer extends JavaScriptObject {    public final native String getFirstName() /*-{         return this.first_name;    }-*/;    public final native void setFirstName(String value) /*-{        this.first_name = value;    }-*/;    public final native String getLastName() /*-{        return this.last_name;    }-*/;    public final native void setLastName(String value) /*-{        this.last_name = value;    }-*/;}

Once you have the overlay type defined, it's easy to create a JavaScript object from JSON and access its properties in Java:

public static final native Customer buildCustomer(String json) /*-{    return eval('(' + json + ')');}-*/;

If you want the JSON representation of the object again, you can wrap the overlay type in a JSONObject:

Customer customer = buildCustomer("{'Bart', 'Simpson'}");customer.setFirstName("Lisa");// Displays {"first_name":"Lisa","last_name":"Simpson"}Window.alert(new JSONObject(customer).toString());

Another thing to try is the new AutoBean framework introduced with GWT 2.1.

You define interfaces for your beans and a factory that vends them, and GWT generates implementations for you.

interface MyBean {  String getFoo();  void setFoo(String foo);}interface MyBiggerBean {  List<MyBean> getBeans();  void setBeans(List<MyBean> beans>;}interface Beanery extends AutoBeanFactory{  AutoBean<MyBean> makeBean();  AutoBean<MyBiggerBean> makeBigBean();}Beanery beanFactory = GWT.create(Beanery.class);void go() {  MyBean bean = beanFactory.makeBean().as();  bean.setFoo("Hello, beans");}

The AutoBeanCodex can be used to serialize them to and from json.

AutoBean<MyBean> autoBean = AutoBeanUtils.getAutoBean(bean);String asJson = AutoBeanCodex.encode(autoBean).getPayload();AutoBean<MyBean> autoBeanCloneAB =   AutoBeanCodex.decode(beanFactory, MyBean.class, asJson );MyBean autoBeanClone = autoBeanCloneAB.as(); assertTrue(AutoBeanUtils.deepEquals(autoBean, autoBeanClone));

They work on the server side too — use AutoBeanFactoryMagic.create(Beanery.class) instead of GWT.create(Beanery.class).

The simplest way would be to use GWT's built-in JSON API. Here's the documentation. And here is a great tutorial on how to use it.

It's as simple as this:

String json = //json stringJSONValue value = JSONParser.parse(json);

The JSONValue API is pretty cool. It lets you chain validations as you extract values from the JSON object so that exceptions will be thrown if anything's amiss with the format.