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POHow to use Morphia with Java / GWT
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copied!<p>I am trying to use MongoDB with Morphia as my back-end DB, I have implemented a utility class to simplify access to the database. I implemented basic add user function with However I am getting `lots of exceptions: </p> <p><code>java.lang.IndexOutOfBoundsException</code> exception when I put </p> <blockquote> <p>Query query = datastore.createQuery(User.class).filter("name = ", username);</p> </blockquote> <p>for checking user before comitting.</p> <p>When removed: I get these two exceptions:</p> <pre><code>java.lang.RuntimeException: java.lang.NumberFormatException: </code></pre> <p>How to fix this issue? </p> <p>Here are the code I have for the project:</p> <p>MorphiaUtil.java:</p> <pre><code>public class MorphiaUtil { protected final Log log = LogFactory.getLog(getClass()); private static Mongo mongo; private static Datastore datastore; static { try { // Create the database connection mongo = new Mongo("localhost"); datastore = new Morphia().createDatastore(mongo, "mygwtapp"); } catch (UnknownHostException e) { System.err.println("Caught Unknown host exception:"+e); e.printStackTrace(); } catch (MongoException e) { System.err.println("Initial Datastore creation failed:"+e); e.printStackTrace(); } } public static Datastore getDatastore() { return datastore; } } </code></pre> <p>UserServiceImpl.java</p> <pre><code>public class UserServiceImpl extends RemoteServiceServlet implements UserService { @Override public void addUser(String username, String password) throws IllegalArgumentException { try { Datastore datastore = MorphiaUtil.getDatastore(); Query query = datastore.createQuery(User.class).filter("name = ", username); User user = (User) query.asList().get(0); if (user == null) { user = new User(username, password); datastore.save(user); } } catch (Exception e) { System.err.print("Caught exception:"+e); } } } </code></pre>

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