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

Question

I am looking for a simple Json (de)serializer for Java that might work with GWT. I have googled a bit and found some solutions that either require annotate every member or define useless interfaces. Quite a boring. Why don't we have something really simple like

class MyBean {     ... }  new GoodSerializer().makeString(new MyBean()); new GoodSerializer().makeObject("{ ... }", MyBean.class) 

Answer 1

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()); 

Answer 2

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).