如何從servlet重定向到jsp頁面

Question

我使用表單獲取用戶名和密碼並將其與數據庫表值進行比較。如果它們匹配，則應打印用戶名和密碼。它完成..

但是，我需要將它們重定向到另一個頁面，如果它的有效（比如welcome.jsp）在web內容文件夾。我該怎麼做。我是servlet和jsp幫助我。

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

看該方法

HttpServletResponse.sendRedirect(String Location) 

即使用它作爲：

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

或者，看看方法

HttpServletResponse.setHeader(String name, String value) 

重定向是通過將位置標頭設置：

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

Answer 2

請使用下面的代碼，讓我知道

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是你jsp頁的相對路徑。因此，根據您的jsp頁面路徑進行更改。

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(); 
     }