Question

我使用表单获取用户名和密码，并将其与数据库表值进行比较。如果匹配，则应打印用户名和密码。它完成了..

但是，我需要将它们重定向到另一个页面，如果它在web内容文件夹中有效（例如welcome.jsp）。我该怎么做。我是servlet的新手，jsp帮助我。

SaveServlet.java

package myPack;

    import java.io.IOException;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.Statement;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;

    /**
     * Servlet implementation class SaveServlet
     */
    public class SaveServlet extends HttpServlet {
        private static final long serialVersionUID = 1L;

        /**
         * Default constructor. 
         */
        public SaveServlet() {
            // TODO Auto-generated constructor stub
        }

        /**
         * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
         */
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            // TODO Auto-generated method stub
            String u = request.getParameter("username");
            String p=request.getParameter("password");
            System.out.println("USER-->"+u);
            ResultSet rs;
            String q="select * from userinfo where username='"+u+"' and password='"+p+"'";
            Connection con=null;



            String c="jdbc:mysql://localhost:3306/test";

            try{

                Class.forName("com.mysql.jdbc.Driver").newInstance();
                con = DriverManager.getConnection(c, "root", "MyNewPass");
                System.out.println("connection done");


                PreparedStatement ps=con.prepareStatement(q);
                System.out.println(q);
                rs=ps.executeQuery();
                System.out.println("done2");
                while (rs.next()) {
                   System.out.println(rs.getString(1));
                   System.out.println(rs.getString(2));

                }

            }
                catch (Exception e) {
                    // TODO: handle exception
                    System.out.println("Failed");
                }

        }

        /**
         * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
         */
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            // TODO Auto-generated method stub
            doGet(request, response);
        }

    }

Answer 1

查看方法

HttpServletResponse.sendRedirect(String Location)

即。用它作为：

HttpServletResponse.sendRedirect("/your/new/location.jsp")

或者，看看方法

HttpServletResponse.setHeader(String name, String value)

通过添加位置标题来设置重定向：

HttpServletResponse.setHeader("Location", "/your/new/location.jsp");

Answer 2

请使用以下代码告诉我

try{

            Class.forName("com.mysql.jdbc.Driver").newInstance();
            con = DriverManager.getConnection(c, "root", "MyNewPass");
            System.out.println("connection done");


            PreparedStatement ps=con.prepareStatement(q);
            System.out.println(q);
            rs=ps.executeQuery();
            System.out.println("done2");
            while (rs.next()) {
               System.out.println(rs.getString(1));
               System.out.println(rs.getString(2));

            }

         response.sendRedirect("myfolder/welcome.jsp"); // wherever you wanna redirect this page.

        }
            catch (Exception e) {
                // TODO: handle exception
                System.out.println("Failed");
            }

myfolder/welcome.jsp 是您jsp页面的相对路径。因此，请根据您的jsp页面路径进行更改。

Answer 3

    String u = request.getParameter("username");
    String p = request.getParameter("password");

    try {
        st = con.createStatement();
        String sql;
        sql = "SELECT * FROM TableName where USERNAME = '" + u + "' and PASSWORD = '"
                + p + "'";
        ResultSet rs = st.executeQuery(sql);
        if (rs.next()) {
            RequestDispatcher requestDispatcher = request
                    .getRequestDispatcher("/home.jsp");
            requestDispatcher.forward(request, response);
        } else {

            RequestDispatcher requestDispatcher = request
                    .getRequestDispatcher("/invalidLogin.jsp");
            requestDispatcher.forward(request, response);

        }

    } catch (Exception e) {
        e.printStackTrace();
    }
    finally{
        try {
            rs.close();
            ps.close();
            con.close();
            st.close();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

如何从servlet重定向到jsp页面

3 个答案: