如何从IBM WSJdbc41Connection解开PostgreSQL连接

问题描述

我一直在尝试从IBM JNDI(WebSphere liberty)解开PostgreSQL连接，但是没有运气，请提供任何帮助:

I have been trying to unwrap PostgreSQL connection from the IBM JNDI (WebSphere liberty ) and have had no luck please any help with that :

         Context ctx = new InitialContext();
        DataSource dataSource = (DataSource) ctx.lookup("jdbc/indi");
        Connection cnx = dataSource.getConnection();

我收到此异常:

 java.lang.ClassCastException:
     com.ibm.ws.rsadapter.jdbc.v41.WSJdbc41Connection cannot be cast to
     org.postgresql.PGConnection

我尝试过:

if(cnx.isWrapperFor(PGConnectionPoolDataSource.class)) {
        //unwrap
    }
    if (cnx.isWrapperFor(org.postgresql.ds.jdbc4.AbstractJdbc4SimpleDataSource.class)) {
            //unwrap
    }

    if (cnx.isWrapperFor(org.postgresql.core.v3.ConnectionFactoryImpl.class)) {
            //unwrap
    }
    if (cnx.isWrapperFor(org.postgresql.jdbc2.AbstractJdbc2Connection.class)) {
            //unwrap
    }
    if (cnx.isWrapperFor(org.postgresql.jdbc3.AbstractJdbc3Connection.class)) {
            //unwrap
    }

谢谢

推荐答案

如果要将JDBC对象(数据源，连接等)解包到特定于供应商的接口，请在已配置的中将JDBC驱动程序<; datSource> 必须对应用程序类加载器可用.配置将如下所示:

If you would like to unwrap a JDBC object (DataSource, Connection, etc) to a vendor-specific interface, the JDBC driver in the configured <datSource> must be available to the application classloader. The configuration will look something like this:

<application location="oraclejdbcfat.war" >
    <!-- expose the 'DBLib' containing the JDBC driver jar to the app classloader -->
    <classloader commonLibraryRef="DBLib"/>
</application>

<library id="DBLib">
    <fileset dir="${server.config.dir}/postgresql/" includes="*.jar"/>
</library>

<dataSource jndiName="jdbc/myDS">
    <jdbcDriver libraryRef="DBLib"/>
    <properties .../>
</dataSource>

从那里，您可以像以前一样解开对象，即:

From there, you can unwrap the object in the same way you were doing before, namely:

DataSource ds = InitialContext.doLookup("jdbc/myDS");
Connection conn = ds.getConnection();
PGConnection pgConn = conn.unwrap(org.postgresql.PGConnection.class);

---

此外，在< dataSource> 配置上还有一个 enableConnectionCasting 布尔属性，该属性会在 getConnection()时自动为您调用unwrap.

---

Also, there is an enableConnectionCasting boolean attribute on <dataSource> configuration which will automatically call unwrap for you upon getConnection().

<dataSource jndiName="jdbc/myDS" enableConnectionCasting="true">

然后，Java代码会更简单:

Then the java code is a bit simpler:

DataSource ds = InitialContext.lookup("jdbc/indi");
PGConnection pgConn = (PGConnection) ds.getConnection();

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