Javaweb新手,配置jndi后连接数据后总出现异常
报错出现在 myConn = ds.getConnection();

修改my.ini后还是会出现这种问题

配置jndi的context.xml文件

web.xml文件

    
        jdbc/studentinfo
        javax.sql.DataSource
        Container
    
    
    
        StudentServlet
        init.StudentServlet
    
    
        StudentServlet
        /StudentServlet
    

java文件

public class StudentServlet extends HttpServlet{
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        response.setContentType("text/html;charset=GB2312");
        PrintWriter out = response.getWriter();

        out.println("");
        out.println("");
        if((request.getParameter("sno") == null || request.getParameter("sno").equals("input number"))){
            out.println("
");
            out.println("");
            out.println("学号查询：");
            out.println("
");
            out.println("
");
        }else if (!(request.getParameter("sno").equals("input number"))){
            Vector vc = new Vector();

            out.println("
");
            out.println("");
            out.println("学生学号：");
            out.println("
");
            out.println("
");
            out.println("");
            out.println("");

            try {
                if((vc = accessDB(Integer.parseInt((String)request.getParameter("sno")))) != null){
                    out.println("");
                    out.println("");
                    out.println("");
                    out.println("");
                    out.println("");
                    out.println("");
                }
            }catch (Exception e){
                out.println("");
                out.println("");
                out.println("");
                out.println("数据库里没有你要查询得记录");
                e.printStackTrace();
            }
            out.println("
学号
姓名
语文
数学
" + vc.elementAt(0) + "
" + vc.elementAt(1) + "
" + vc.elementAt(2) + "
" + vc.elementAt(3) + "
没有记录：
");
        }
        out.println("");
        out.println("");
        out.flush();
        out.close();
    }

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

    @Override
    public void init() throws ServletException {

    }

    public Vector accessDB(int id){
        Vector vc = new Vector();
        DataSource ds = null;
        Context ctx;
        Connection myConn = null;

        try {
            ctx = new InitialContext();
            ds = (DataSource) ctx.lookup("java:comp/env/jdbc/studentinfo");
        }catch (Exception e){
            e.printStackTrace();
        }

        if (ds == null){
            System.out.println("Error");
        }else {
            System.out.println("Connection is OK!");
        }

        PreparedStatement statement = null;
        ResultSet mySet = null;
        try {
           myConn = ds.getConnection();
            statement = myConn.prepareStatement("SELECT * FROM info WHERE sno=?");
            statement.setInt(1,id);
            mySet = statement.executeQuery();

            while (mySet.next()){
                vc.add(Integer.toString(mySet.getInt("sno")));
                vc.add(mySet.getString("sname"));
                vc.add(Integer.toString(mySet.getInt("chinese")));
                vc.add(Integer.toString(mySet.getInt("math")));
            }

            statement.close();
            mySet.close();
            myConn.close();
            return vc;
        }catch (Exception e){
            e.printStackTrace();
        }
        return vc;
    }

    public static void main(String[] args) {
        StudentServlet aa = new StudentServlet();
        System.out.println(aa.accessDB(100).elementAt(1));
    }
}

修改context.xml的urlurl="jdbc:mysql://localhost:3306/studentinfo?useSSL=true"

还是会出现异常如下：
java.sql.SQLException: Cannot create PoolableConnectionFactory (Unknown system variable 'lower_case_table_names')

at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:2303)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:2043)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1543)
at init.StudentServlet.accessDB(StudentServlet.java:102)
at init.StudentServlet.doGet(StudentServlet.java:47)