在 TomEE 中使用来自 context.xml 的 JDBC 数据源

Question

TomEE is a great project, combining the lightweight experience of Tomcat with Java EE features. I have many JDBC datasources declared in context.xml, but when I want to use that Datasource via JNDI I get an Exception. So how can I get working a JDBC datasource declared in context.xml in TomEE

My datasource declared in context.xml

 <Resource auth="Container" 
        name="local_jdbc_db"  
        type="javax.sql.DataSource" 
        driverClassName="com.mysql.jdbc.Driver"  
        url="jdbc:mysql://localhost:3306/mydb" 
        username="user" 
        password="pass"      /> 

The code to get the Datasource from JNDI

Context contextoInicial = new InitialContext();
Context contexto = (Context) contextoInicial.lookup("java:comp/env");
DataSource ds= (DataSource) contexto.lookup("local_jdbc_db");

Answer 1

UPDATE Just to anyone having this rare problems with TomEE: I tried creating datasources in context.xml and deploying in TomEE JAX-RS version 1.5.0 with no luck, it always throws me null pointer exceptions and datasource name not found. Recently I tried the same with TomEE JAX-RS version 1.6.0: I created my datasource in context.xml and create a simple servlet with this code

     Context initContext = new InitialContext();
     Context envContext = (Context) initContext.lookup("java:/comp/env");
     DataSource dataSource = (DataSource) envContext.lookup("jdbc_northwind");
     try (Connection conn = dataSource.getConnection(); 
           Statement s = conn.createStatement();
           ResultSet rs = s.executeQuery("select * from customers")) {
           while (rs.next()) {
                out.print(rs.getString("CompanyName"));
                out.print("<br>");
           }         
       } 

... started the server and Hooray !!!! It shows me results!, but I was a bit was disappointed because when I redeployed the application it shows me the old exceptions (DataSource not found, null pointer exception) So I tried the last thing: register the datasource in web.xml

  <resource-ref>
        <res-ref-name>jdbc_northwind</res-ref-name>
        <res-type>javax.sql.DataSource</res-type>
        <res-auth>Container</res-auth>
        <res-sharing-scope>Shareable</res-sharing-scope>
    </resource-ref> 

And restart the server and... It works, redeploy the application and works very fine!, But this behaviour is quite strange: in Tomcat I never declared my datasource in web.xml and I have no problem with datasources. Maybe a bug?

UPDATE: Confirmed is a bug, seems like it will be solved for TomEE 1.6.1 UPDATE 2: Solved in TomEE 1.7.0

Answer 2

Have you looked at the documentation? http://tomcat.apache.org/tomcat-6.0-doc/jndi-datasource-examples-howto.html Additionally, can you provide the exception that you are receiving?

Answer 3

Because I spent so many hours with this problem which I finally found the answer within 15min of reading the manual (RTFM) for this subject at: http://tomee.apache.org/configuring-datasources.html

The proper JNDI namespace for database resources in tomee.xml is: "java:openejb/Resource/..."

Just leaving this here just in case someone else comes looking for this issue.

I cannot emphasize enough how much time I wasted on this when I could have just read the manual. Oh well :-)