servlet 校验密码

一、实现效果图

登陆成功：

用户不存在：

密码错误：

二、数据库连接代码：

首先要先将jdbc的jar包导入项目中，具体怎么做，网上也有，就不写出来了。

package com.serverlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

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

/**
 * Servlet implementation class login_servlet
 */
@WebServlet("/login_servlet")
public class login_servlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public login_servlet() {
        super();
        // 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
         
            Connection conn=null;
            Statement stmt = null;
            response.setContentType("text/html;charset=utf-8");
            try {
                Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");//驱动
                PrintWriter out =response.getWriter();
                conn=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;databasename=Company","www","www");//连接数据库
                stmt =conn.createStatement();
                 
                String un=request.getParameter("uname");
                String upwd = request.getParameter("upass");
                //out.println(upwd+"/n");
                String sql = "Select sex from t_ly where name ='"+un+"'";
                ResultSet rs = stmt.executeQuery(sql);//执行sql语句
                boolean isTrue = false;
            //  boolean isLoginIn = false;
                while(rs.next()){//遍历整个数据库
                    String pswd = rs.getString("sex");//取出数据库数据
                    //out.println(pswd.replace(" ", ""));
                    if(pswd.replace(" ", "").equals(upwd))
                    {
                        isTrue=true;
                        out.println("欢迎您："+un);
                        break;
                    }
                    else
                    {
                        isTrue= true;
                        out.println("密码错误，登陆失败");
                    }
                 
                }
                if(isTrue==false)
                {
                    out.println("用户名不存在");
                }
             
                rs.close();
                stmt.close();
                conn.close();
                 
         
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }
        finally
            {
                try {
                    if(stmt!=null)
                    {
                        stmt.close();
                         
                    }
                } catch (Exception e) {
                    // TODO: handle exception
                }
                try {
                    if(conn!=null)
                    {
                        conn.close();
                    }
                } catch (Exception e) {
                    // TODO: handle exception
                }
                 
                     
            }
         
        }
     
        /**
         * @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);
        }
        public void  destroy()
        {
             
        }
     
    }

三、连接

链接：https://pan.baidu.com/s/16cDICRmW-LCpeiaeYF64vg
提取码：oytd
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