Question

我为代表创建Restful Web服务，以便从UI登录并通过JDBC连接到Mysql数据库。在Windows 10上使用动态Web服务-web模块版本2.5，Apache Tomcat服务器8.0.我在Java类中编写了Query并且连接到数据库。当运行tomcat服务器..它转到ui并且当单击提交按钮时，下一步操作是连接到DB但它的抛出：

UI和控制台中的Java.null.point.exception com.mysql.jdbc.CommunicationsException：通信链接失败由于潜在的例外：**开始嵌入异常** java.io.EOFException的

public class loginservlet6_1 extends HttpServlet {

    private static final long serialVersionUID = 1L;
    Connection con=null;
    Statement st=null;
    ResultSet rs=null;

    public void init(ServletConfig config)
    {
        try
        {
            System.out.println("Database connectionestablishment");
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://localhost:1002/root","root","root");
    //(jdbc:mysql://localhost:portnum/dbname , username,password)
            System.out.println("Database conn established");
        }
        catch(Exception e)
            {
                System.out.println(e);
            }
    }



    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        PrintWriter out = response.getWriter();
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        try
        {
            st = con.createStatement();
                    rs = st.executeQuery("select UserName,Password from reps where UserName='"+username+"' and Password='"+password+"'");
            while(rs.next())
            {
                System.out.println("Username : "+rs.getString(1)+"  Password : "+rs.getString(2));

                if(username.equals(rs.getString(1)) && password.equals(rs.getString(2))){  
                JOptionPane.showMessageDialog(null,"Login Successful");
                response.sendRedirect("/login.html");
                }
                else
                {
                    JOptionPane.showMessageDialog(null,"Login Not Successful");
                    /*RequestDispatcher rd = request.getRequestDispatcher("/RegisterServlet");
                    rd.forward(request, response);
                    */
                    response.sendRedirect("/TestDemo6/login.html");
                }

            }


        }
        catch(Exception e){
            out.println(e);
        }
    }
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);

    }
    public void destroy()
    {
        try {
            rs.close();
        } catch (SQLException se) {
            se.printStackTrace();
        }
        try {
            st.close();
        } catch (SQLException e) {
                    e.printStackTrace();
                }
        try {con.close();
        } catch (SQLException e) {
                e.printStackTrace();
        }
    }
}

web services.Error：com.mysql.jdbc.CommunicationsException：通信链接失败java.io.EOFException

0 个答案: