How to use a JNDI Resource in a JAX-RS (Jersey) Application? - mysql

Question

I'm trying to set up a connection to my database through a Tomcat JNDI resource. I've been looking at many articles today and I can't seem to find an answer.
In my server.xml I have:
<GlobalNamingResources>
<Resource name="jdbc/MyDB" auth="Container" type="javax.sql.DataSource"
maxActive="100" maxIdle="30" maxWait="10000"
username="tomcat" password="...."
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3333/tomcat?autoReconnect=true"/>
.....
</GlobalNamingResources>
In my web service, I attempt to access the resource with:
InitialContext ctx = new InitialContext();
DataSource data = (DataSource)ctx.lookup("java:comp/env/jdbc/MyDB");
Connection conn = data.getConnection();
When I run the code, I get this exception:
Nov 2, 2011 1:06:20 PM com.sun.jersey.spi.container.ContainerResponse mapMappableContainerException
SEVERE: The exception contained within MappableContainerException could not be mapped to a response, re-throwing to the HTTP container
javax.naming.NameNotFoundException: Name jdbc is not bound in this Context
...
I have the newest mysql-connector-java-5.1.18-bin.jar in both my web-app's lib and my tomcat lib.
Can you please help me get this working?

Answer 1

I use this code, with only the name of the resource, and it works:
private Connection getConnection(){
final Context ctx = new InitialContext();
final DataSource ds = (DataSource) ctx.lookup("jdbc/MyDB");
if (ds != null)
{
return ds.getConnection();
}
else
{
}
}

Answer 2

We just need to mention the jndi name after java:
In your case:
InitialContext ctx = new InitialContext();
DataSource data = (DataSource)ctx.lookup("java:/jdbc/MyDB");
Connection conn = data.getConnection();
Because you configured in your server.xml as below:
<GlobalNamingResources>
<Resource name="jdbc/MyDB" auth="Container" type="javax.sql.DataSource"
maxActive="100" maxIdle="30" maxWait="10000"
username="tomcat" password="...."
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3333/tomcat?autoReconnect=true"/>
.....
</GlobalNamingResources>

Answer 3

My solution was to switch to a properties file for the database information and then utilize it with entity manager.
import java.io.FileReader;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.servlet.ServletException;
import org.eclipse.persistence.config.EntityManagerProperties;
import org.eclipse.persistence.config.PersistenceUnitProperties;
...
Properties properties = new Properties();
FileReader fr = new FileReader(Constants.Config.getPropertiesFile());
properties.load(fr);
// connect to the database
Map<String,String> emMap = new HashMap<String,String>();
emMap.put(PersistenceUnitProperties.APP_LOCATION, Constants.Config.getAppDir());
emMap.put(EntityManagerProperties.JDBC_USER, properties.getProperty("db.username"));
emMap.put(EntityManagerProperties.JDBC_PASSWORD, properties.getProperty("db.password"));
// iterate over these properties attempting to read them in and connect to the url
List<?> dbProps = Collections.list(properties.keys());
Collections.sort(dbProps, new Comparator<Object>() {
#Override
public int compare(Object o1, Object o2) {
return o1.toString().compareTo(((String)o2));
}
});
for(Object propKey : dbProps){
// support multiple database key/values in the eform db.url, db.url1, ... db.urlN
if(!propKey.toString().matches("db.url\\d*")){
continue;
}
String dbLocation = properties.getProperty(propKey.toString());
try {
if(dbLocation == null) continue;
emMap.put(EntityManagerProperties.JDBC_URL, dbLocation);
EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("db", emMap);
em = entityManagerFactory.createEntityManager();
// ensure we're connected by executing a no-op query
em.createNativeQuery("select current_database()").getSingleResult(); // will only work for postgresql
properties.put("db.connected", dbLocation);
break;
}
catch (javax.persistence.PersistenceException e) {
Utility.logger(DataHolder.class).error("Couldn't connect to " + dbLocation);
}
}