java.lang.AbstractMethodError: com.mysql.jdbc.Conn

问题:

I am trying to connect my Servlet to mysql database using data Source . But whenever I run my servlet I end up getting this exception :

java.lang.AbstractMethodError: com.mysql.jdbc.Connection.isValid(I)Z
    org.apache.tomcat.dbcp.dbcp2.DelegatingConnection.isValid(DelegatingConnection.java:913)
    org.apache.tomcat.dbcp.dbcp2.PoolableConnection.validate(PoolableConnection.java:282)
    org.apache.tomcat.dbcp.dbcp2.PoolableConnectionFactory.validateConnection(PoolableConnectionFactory.java:356)
    org.apache.tomcat.dbcp.dbcp2.BasicDataSource.validateConnectionFactory(BasicDataSource.java:2306)
    org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:2289)
    org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:2038)
    org.apache.tomcat.dbcp.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1532)
    Servlet.AbdulTayyebs.processRequest(AbdulTayyebs.java:36)
    Servlet.AbdulTayyebs.doGet(AbdulTayyebs.java:57)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

Here is my Content.xml

<Resource name="jdbc/abdultayyebs" auth="Container"
          type="javax.sql.DataSource" driverClassName="com.mysql.jdbc.Driver"
          url="jdbc:mysql://127.0.0.1:4000/abdultayyebs?zeroDateTimeBehavior=convertToNull"
          username="root" password="february1996" maxActive="5" maxIdle="2"
          maxWait="1000"/>

Here is my web.xml

  <resource-ref>
  <description>DB Connection</description>
  <res-ref-name>jdbc/abdultayyebs</res-ref-name>
  <res-type>javax.sql.DataSource</res-type>
  <res-auth>Container</res-auth></resource-ref>

And here is my servlet AbdulTayyebs

 import java.io.IOException;
 import java.io.PrintWriter; 
 import java.sql.Connection;
 import java.sql.SQLException;
 import javax.naming.Context;
 import javax.naming.InitialContext;
 import javax.servlet.ServletConfig;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.sql.DataSource;

 public class AbdulTayyebs extends HttpServlet {

  DataSource ds=null;  

 @Override
 public void init(ServletConfig config)throws ServletException{
    try {
     Context initContext = new InitialContext();
     Context envContext  = (Context)initContext.lookup("java:/comp/env");
     ds = (DataSource)envContext.lookup("jdbc/abdultayyebs");  
    } catch (Exception e) {
     throw new ServletException("Something went wrong while Initializing the Servlet",e);
    }
  }

    protected void processRequest(HttpServletRequest request,                   
       HttpServletResponse response)
       throws ServletException,IOException {
       PrintWriter write = response.getWriter();
       try {   
       Others.Action a = Others.ActionFactory.CreateAction(request);
     try(Connection c=ds.getConnection()){
     String page = a.Execute(c,request,request.getSession(false));
       request.getRequestDispatcher(page).forward(request, response); 
      }      
   }     
   catch (SQLException e) {
     write.println(e);
   }
   catch (ServletException e) {
     write.println(e);     
   }
   catch (Exception e) {       
    write.println(e);
   }   
 }

 @Override
 protected void doGet(HttpServletRequest request, HttpServletResponse  response)
        throws ServletException, IOException {
      processRequest(request, response);
   }

@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
     processRequest(request, response);
     } 
   }

I also added the mysql jdbc driver in the lib folder of tomcat but even this didnt helped ? It would be highly appreciable if anybody can help me out

回答1:

java.lang.AbstractMethodError: com.mysql.jdbc.Connection.isValid(I)Z

This means that the MySQL JDBC driver is outdated as such that it doesn't support Java 1.6's Connection#isValid() method.

Upgrade it. And make sure that you've only one MySQL JDBC driver JAR file in the runtime classpath.

See also:

• Connect Java to a MySQL database

回答2:

For me, the solution was not to upgrade my driver (JT400). Even the latest version (9.1) appears to not have implemented isValid() (it's commented out in the code?).

What worked for me was to provide a validationQuery to my database connection pool. E.g.:

validationQuery=SELECT current date FROM sysibm.sysdummy1

回答3:

net.sourceforge.jtds.jdbc.JtdsConnection doesn't implement isValid()

So you need to specify a connection-test-query to ensure that isValid() method isn't called Adding the following line to application.propertiesfile resolved the error for me.

spring.datasource.hikari.connection-test-query=SELECT 1

回答4:

in my case, I upgraded ojdbc from verion 14 to 6. I had artifact ojdbc14, then I changed it to ojdbc6. I lost quite sometime here, as I thought 14 is a later version as 14>6. but 14 is meant for java 1.4. 6 means java6