net.ucanaccess.jdbc.UcanaccessSQLException 游标状态无效

Posted 2023-04-19

【中文标题】net.ucanaccess.jdbc.UcanaccessSQLException 游标状态无效

【英文标题】：net.ucanaccess.jdbc.UcanaccessSQLException invalid cursor state

【发布时间】：2015-04-30 16:47:40

【问题描述】：

我收到以下错误。任何人都可以在下面提供帮助吗？ 我在数据库中有 2 行。 问题是我猜结果集光标没有移动

控制台日志：

connection established...
rs execute...
rs is not null
rs is not next...
inside while....
inside do post catch 
**net.ucanaccess.jdbc.UcanaccessSQLException: invalid cursor state: identifier cursor not positioned on row in UPDATE, DELETE, SET, or GET statement: ; ResultSet is empty**
    at net.ucanaccess.jdbc.UcanaccessResultSet.getInt(UcanaccessResultSet.java:452)
    at com.test.myservlettest.doPost(myservlettest.java:93)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1074)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    **at java.lang.Thread.run(Unknown Source)
Caused by: java.sql.SQLException: invalid cursor state: identifier cursor not positioned on row in UPDATE, DELETE, SET, or GET statement: ; ResultSet is empty**
    at org.hsqldb.jdbc.JDBCUtil.sqlException(Unknown Source)
    at org.hsqldb.jdbc.JDBCUtil.sqlException(Unknown Source)
    at org.hsqldb.jdbc.JDBCUtil.sqlException(Unknown Source)
    at org.hsqldb.jdbc.JDBCResultSet.getCurrent(Unknown Source)
    at org.hsqldb.jdbc.JDBCResultSet$JDBCResultSetBasic.getColumnInType(Unknown Source)
    at org.hsqldb.jdbc.JDBCResultSet.getInt(Unknown Source)
    at net.ucanaccess.jdbc.UcanaccessResultSet.getInt(UcanaccessResultSet.java:450)
    ... 23 more
Caused by: org.hsqldb.HsqlException: invalid cursor state: identifier cursor not positioned on row in UPDATE, DELETE, SET, or GET statement: ; ResultSet is empty
    at org.hsqldb.error.Error.error(Unknown Source)
    at org.hsqldb.error.Error.error(Unknown Source)
    at org.hsqldb.error.Error.error(Unknown Source)
    ... 28 more
we are in service method of servlet

Myservlettest（servlet 类）：

public void doPost(HttpServletRequest req, HttpServletResponse res) throws IOException
        System.out.println("Inside Servlet");

        Chintandatabase cd = new Chintandatabase();
        Connection con = null;
        String userid =null;
        String password = null;

        String un =req.getParameter("username") ;
        String pw =req.getParameter("userpass") ;
        String msg =null;

        System.out.println("username from UI: "+un);
        System.out.println("password from UI: "+pw);
        try 
            con = cd.getConnection();
            Statement s = con.createStatement();
            s.executeQuery("select SOE_ID,PASSWORD from User");
            ResultSet rs = s.getResultSet();
            System.out.println("rs execute...");
            if(rs==null)System.out.println("rs is null");
            else System.out.println("rs is not null");

            if(rs.next())System.out.println("rs is next");
            else System.out.println("rs is not next...");

          while (rs.next() || rs!=null) 
                System.out.println("inside while....");
                System.out.println(rs.getInt(1));
                userid  = rs.getString("SOE_ID");
                password =  rs.getString("PASSWORD");
            
            //s.close();
            //con.close();
         catch (SQLException e) 
            System.out.println("inside do post catch ");
            // TODO Auto-generated catch block
            e.printStackTrace();
        
        System.out.println("we are in service method of servlet");


        if ((un.equalsIgnoreCase(userid) && pw.equals(password)))

            msg="Hello " + un + "! your login is successfull...";
        
        else
            msg="Invalid Credentials...";

        


        res.setContentType("text/html");
        PrintWriter out = res.getWriter();
        out.println("<font size='6' color=red>" + msg + "</font>");
    

Chintandatabase 类：（连接类）

package com.database;

import java.sql.*;
import java.util.logging.Level;
import java.util.logging.Logger;

import com.test.beans.*;


public class Chintandatabase 

    public Connection getConnection() throws SQLException 
        Connection con = null;
        try 
            Class.forName("net.ucanaccess.jdbc.UcanaccessDriver");
            con = DriverManager.getConnection("jdbc:ucanaccess://C:/ChintanDB/ChintanDB.accdb;memory=false");
            System.out.println("connection established...");

         catch (Exception e) 
            System.out.println("inside get connection catch ");
            System.out.println("Exception : " + e);
            e.printStackTrace();
        
        return con;

    

【参考方案1】：

问题是你已经在行中移动了光标：

 if(rs.next())System.out.println("rs is next");
 else System.out.println("rs is not next...");

只需将它们注释掉，您的问题就会得到解决

注意：在下面的这段时间里，你只需要这个：

while (rs.next()) 
  ....

更新 哦，还有我刚刚注意到的其他事情。在 ResultSet 中获取数据的方法如下：

Statement s = con.createStatement();
ResultSet rs = s.executeQuery("select SOE_ID,PASSWORD from User");

查看完整示例here