Question

我是servlet和jsp的新手所以我正在尝试实现视图，添加，更新和删除等操作，但我没有想法实现此操作，如如何转发页面并维护会话并将值传递给jsp如此善良，有些人可能会以正确的方式提供帮助。我已经去了很多教程，但不知道，这里尝试了

Controller.java

    package servlet;

    import java.io.IOException;
    import java.io.PrintWriter;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;

    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;

    import db.Dbconnect;


    public class Controller extends HttpServlet 
    {
        private static final long serialVersionUID = 1L;


        public Controller() 
        {
            super();
        }


        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
        {
        }


        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
        {
            response.setContentType("text/html");
            PrintWriter out=response.getWriter();

             String nam = request.getParameter("name"); 
             String pass = request.getParameter("pass"); 
             String email = request.getParameter("emailid"); 
             String phono = request.getParameter("phone");


        }


        public  void view() throws ClassNotFoundException
        {

            try
            {
                String sql="select * from Reg";
                Class.forName("com.mysql.jdbc.Driver");
                Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/mine", "root", "android");
                Statement stmt=con.createStatement();
                ResultSet rs=stmt.executeQuery(sql);

                while(rs.next())
                {
                    rs.getString("name");
                    rs.getString("pass");
                    rs.getString("emailid");
                    rs.getString("phoneno");
                   System.out.println(rs.getString("name"));

                }

            } 
            catch (SQLException e)
            {
                e.printStackTrace();
            }
            return;

        }

        public  String insertuser() throws SQLException
        {

            String sql = "insert into Reg(name,pass,emailid,phoneno) values(?,?,?,?)";
            Connection con = null;
            PreparedStatement prep = null;

            try
            {
                Class.forName("com.mysql.jdbc.Driver");
                con = DriverManager.getConnection("jdbc:mysql://localhost:3306/mine", "root", "android");
                prep = con.prepareStatement(sql);
                prep.setString(1, "nam");
                prep.setString(2, "pass");
                prep.setString(3, "email");
                prep.setString(4, "phono");
                prep.executeUpdate();
                prep.close();

            } 
            catch (ClassNotFoundException e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();

            }
            return "successfully added";
        }
        public  String update() throws SQLException
        {

            String sql = "update Reg set pass=?,emailid=?,phoneno=? where name=?";
            Connection con = null;
            PreparedStatement prep = null;

            try
            {
                Class.forName("com.mysql.jdbc.Driver");
                con = DriverManager.getConnection("jdbc:mysql://localhost:3306/mine", "root", "android");
                prep = con.prepareStatement(sql);
                prep.setString(1, "nam");
                prep.setString(2, "pass");
                prep.setString(3, "email");
                prep.setString(4, "phono");
                prep.executeUpdate();
                prep.close();

            } 
            catch (ClassNotFoundException e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();

            }
            return "successfully update";
        }

public  String delete() throws SQLException
    {

        String sql = "delete form Reg where name=?";
        Connection con = null;
        PreparedStatement prep = null;

        try
        {
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/mine", "root", "android");
            prep = con.prepareStatement(sql);

        } 
        catch (ClassNotFoundException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();

        }
        return "successfully delete";
    }


    }

Add.jsp ::

<form action="/Controller" method="post">
User name:<input type="text" name="name" >
Password:<input type="password" name="pass">
Email-id<input type="text" name="emailid">
phone number:<input type="text" name="phone">
<input type="submit" value="submit">
</form>

Update.jsp：

<form action="/Controller" method="post">
User name:<input type="text" name="name" >
Password:<input type="password" name="pass">
Email-id<input type="text" name="emailid">
phone number:<input type="text" name="phone">

<input type="submit" value="Update"/>
</form>

的web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>Vweb2</display-name>
  <welcome-file-list>

    <welcome-file>index.jsp</welcome-file>

  </welcome-file-list>
  <servlet>
    <description></description>
    <display-name>Controller</display-name>
    <servlet-name>Controller</servlet-name>
    <servlet-class>servlet.Controller</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Controller</servlet-name>
    <url-pattern>/Controller</url-pattern>
  </servlet-mapping>
</web-app>

这个两页的

View.jsp和delete.jsp我不知道如何将信息servlet检索到jsp

Answer 1

我认为你会得到更好的帮助，例如。 http://danielniko.wordpress.com/2012/04/17/simple-crud-using-jsp-servlet-and-mysql/

Answer 2

对于View.jsp，将表单的方法属性声明为GET。

在下面，

 <form action="/Controller" method="get">

并使用

   protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
    {

       // Your rendering logic
    }

类似地，对delete.jsp使用delete / doDelete（）方法。

您还需要在web.xml中提及映射

在servlet和jsp中插入更新和删除

2 个答案: