SQLException：耗尽结果集

Question

我的JDBC代码有问题。这是相关代码：

/** method for checking password into the Oracle database */
public String CheckUserDB(String userToCheck) throws SQLException {
  String storedPassword;
  if (ds == null) throw new SQLException("No data source");      
  Connection conn = ds.getConnection();
  if (conn == null) throw new SQLException("No connection");

  try {
    conn.setAutoCommit(false);
    boolean committed = false;
    try {
      PreparedStatement passwordQuery = conn.prepareStatement(
        "SELECT passwd from USERS WHERE userz = ?");
      passwordQuery.setString(1, userToCheck);

      ResultSet result = passwordQuery.executeQuery();

      result.next();

      storedPassword = result.getString("passwd");

      conn.commit();
      committed = true;
    } finally {
      if (!committed) conn.rollback();
    }
  }
  finally {               
    conn.close();
  }       
  return storedPassword;
}

这是例外：

java.sql.SQLException: Exhausted Resultset
    oracle.jdbc.driver.OracleResultSetImpl.getString(OracleResultSetImpl.java:1270)
    oracle.jdbc.driver.OracleResultSet.getString(OracleResultSet.java:494)
    org.jboss.jca.adapters.jdbc.WrappedResultSet.getString(WrappedResultSet.java:1359)
    com.dx.sr_57.user_check.CheckUserDB(user_check.java:100)
    com.dx.sr_57.user_check.user_compare(user_check.java:123)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    java.lang.reflect.Method.invoke(Method.java:601)
    org.apache.el.parser.AstValue.invoke(AstValue.java:196)
    org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:276)
    com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
    javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:88)
    com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
    javax.faces.component.UICommand.broadcast(UICommand.java:315)
    javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
    javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
    com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
    com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
    javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)

这是怎么引起的，我该如何解决？

Answer 1

result.next();

storedPassword = result.getString("passwd");

您没有检查next的返回值。如果没有行，就会遇到麻烦…

if(result.next()){
   storedPassword = result.getString("passwd");
}