netbeans 用户登陆.

最新推荐文章于 2021-06-21 14:12:51 发布

原创最新推荐文章于 2021-06-21 14:12:51 发布 · 1.9k 阅读

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#netbeans #string #servlet #import #sql #jdbc

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本文介绍了一个基于Java的登录验证系统实现，包括了数据库连接、查询操作及表单处理等核心功能。此外，还展示了如何通过JSP进行数据插入、更新与删除等基本CRUD操作。

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/*
* Login.java
*
* Created on 2006年3月26日, 下午9:12
*/

import java.io.*;
import java.net.*;
import java.sql.*;
import java.util.*;
import java.io.*;

import javax.servlet.*;
import javax.servlet.http.*;

/**
*
* @author Administrator
* @version
*/
public class Login extends HttpServlet {
    String DBDriver="org.gjt.mm.mysql.Driver";
    String ConnStr="jdbc:mysql://localhost/cendy";
    String MyUser="root";
    String MyPassword="";
    Connection conn = null;
    ResultSet rs = null;
     public void init() throws ServletException {

         try
        {
            Class.forName(DBDriver);
        }
        catch(java.lang.ClassNotFoundException e){
            System.err.println("DBconn (): " + e.getMessage());
        }
     }
     public ResultSet executeQuery(String sql){
        rs = null;
        try
        {
            conn = DriverManager.getConnection(ConnStr,MyUser,MyPassword);
            Statement stmt = conn.createStatement();
            rs = stmt.executeQuery(sql);
        }
        catch(SQLException ex){
            System.err.println("aq.executeQuery:"+ex.getMessage());
        }
        return rs;
    }
     public String getStr(String str)
{
try
{
  String temp_p=str;
  byte[] temp_t=temp_p.getBytes("ISO8859-1");
  String temp=new String(temp_t);
  return temp;
}
catch(Exception e)
{

}
return "null";
}

    /** Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
     * @param request servlet request
     * @param response servlet response
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        String logname,logpass;
        String errorMessage;
        HttpSession session=request.getSession(true);
        logname=getStr(request.getParameter("username"));
logpass=getStr(request.getParameter("passwd"));
        String sql="select*from username where username='"+logname+"' and passwd='"+logpass+"'";
        ResultSet RS=executeQuery(sql);
int rowscount=0;
try
{
  while(RS.next())
  {
   rowscount++;
  }
}
catch(Exception e)
{
            e.printStackTrace();
}
        if(rowscount!=0)
{
  errorMessage="成功登陆";
  session.setAttribute("username",logname);
                response.sendRedirect("main.jsp");
        }
        else
        {
errorMessage="登陆失败";
session.setAttribute("username","");
          response.sendRedirect("index.jsp?err="+getStr(errorMessage));
}
        out.println("<html>");
        out.println("<head>");
        out.println("<title>Servlet Login</title>");
        out.println("</head>");
        out.println("<body>");
        out.println("<h1>Servlet Login at " + logname + logpass+"</h1>");
        out.println("</body>");
        out.println("</html>");
        out.close();
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /** Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

    /** Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }

    /** Returns a short description of the servlet.
     */
    public String getServletInfo() {
        return "Short description";
    }
    // </editor-fold>
    public void destroy() {
}
}

-------------

String content,content2,content3,content4,content5,content6,content7,content8;
content=request.getParameter("info_title");
content2=request.getParameter("marttype");
content3=request.getParameter("Educ_level");
content4=request.getParameter("Salary");
content5=request.getParameter("info_content");
content6=request.getParameter("end_time");
content7=request.getParameter("work_loc_1st");
content8=request.getParameter("contact");
String sql="insert into com_info(info_title,marttype,Educ_level,Salary,info_content,end_time,work_loc_1st,contact)Values('"+content+"','"+content2+"','"+content3+"','"+content4+"','"+content5+"','"+content6+"','"+content7+"','"+content8+"')";
//out.println(sql);
int num=stmt.executeUpdate(sql);
response.sendRedirect("index.jsp");
out.print("数据库操作成功，恭喜你");
//rs.close();
stmt.close();
conn.close();

%>
----------------------

<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.sql.*"%>
<%
String sDBDriver = "sun.jdbc.odbc.JdbcOdbcDriver";
String url = "jdbc:odbc:cJOB";
String user="sa";
String password="aspnet";
Connection conn= DriverManager.getConnection(url,user,password);
Statement stmt=conn.createStatement();
String id,act,sql,sql2,content,content2;
id=request.getParameter("id");
act=request.getParameter("Submit");
content=request.getParameter("info");
content2=request.getParameter("info2");
sql2="delete com_info where id="+id;
int num=stmt.executeUpdate(sql2);
stmt.close();
conn.close();
response.sendRedirect("numdel.jsp");
%>

-----------

<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.sql.*"%>
<%
//String sDBDriver = "sun.jdbc.odbc.JdbcOdbcDriver";
String url = "jdbc:odbc:cJOB";
String user="sa";
String password="aspnet";
Connection conn= DriverManager.getConnection(url,user,password);
Statement stmt=conn.createStatement();
String id,act,sql,sql2,content,content2;
id=request.getParameter("id");
//act=request.getParameter("Submit");
content=request.getParameter("info");
content2=request.getParameter("info2");
sql="update com_info set info_title='"+content+"',marttype='"+content2+"' where id="+id;
int num=stmt.executeUpdate(sql);
response.sendRedirect("numup.jsp");
stmt.close();
conn.close();
%>

--------------

<%@ page contentType="text/html;charset=gb2312"%>
<%
//变量声明
java.sql.Connection sqlCon; //数据库连接对象
java.sql.Statement sqlStmt; //SQL语句对象
java.sql.ResultSet sqlRst; //结果集对象
java.lang.String strCon; //数据库连接字符串
java.lang.String strSQL; //SQL语句
int intPageSize; //一页显示的记录数
int intRowCount; //记录总数
int intPageCount; //总页数
int intPage; //待显示页码
java.lang.String strPage;

java.lang.String sDBDriver;
java.lang.String url;
java.lang.String user;
java.lang.String password;
int i;
//设置一页显示的记录数
intPageSize = 10;
//取得待显示页码
strPage = request.getParameter("page");
if(strPage==null){//表明在QueryString中没有page这一个参数，此时显示第一页数据
intPage = 1;
}
else{//将字符串转换成整型
intPage = java.lang.Integer.parseInt(strPage);
if(intPage<1) intPage = 1;
}

sDBDriver = "sun.jdbc.odbc.JdbcOdbcDriver";
url = "jdbc:odbc:ycnews";
user="sa";
password="aaaaa";

sqlCon = java.sql.DriverManager.getConnection(url,user,password);
//创建一个可以滚动的只读的SQL语句对象
sqlStmt = sqlCon.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY);
//准备SQL语句
strSQL = "select*from article";
//执行SQL语句并获取结果集
sqlRst = sqlStmt.executeQuery(strSQL);
//获取记录总数
sqlRst.last();
intRowCount = sqlRst.getRow();
//记算总页数
intPageCount = (intRowCount+intPageSize-1) / intPageSize;
//调整待显示的页码
if(intPage>intPageCount) intPage = intPageCount;
%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>JSP数据库操作例程 - 数据分页显示 - JDBC 2.0 - Oracle</title>
</head>
<body>
<table border="0" cellspacing="1" cellpadding="1" width="475" align="center">
<tr bgcolor="#FF9900">
    <th height="20"> 标题</th>
    <th>时间</th>
</tr>
<%
if(intPageCount>0){
//将记录指针定位到待显示页的第一条记录上
sqlRst.absolute((intPage-1) * intPageSize + 1);
//显示数据
i = 0;
while(i<intPageSize && !sqlRst.isAfterLast()){
%>
<tr bgcolor="#EFEFEF">
    <td height="25"><%=sqlRst.getString("title")%></td>
    <td><%=sqlRst.getString("addtime")%> </td>
</tr>
<%
sqlRst.next();
i++;
}
}
%>
</table>
<div align="center">第<%=intPage%>页  共<%=intPageCount%>页  
<%if(intPage<intPageCount){%>
<a href="pages.jsp?page=<%=intPage+1%>">下一页</a>
<%}%>
  
<%if(intPage>1){%>
<a href="pages.jsp?page=<%=intPage-1%>">上一页</a>
<%}%>
</div>
</body>
</html>
<%
//关闭结果集
sqlRst.close();
//关闭SQL语句对象
sqlStmt.close();
//关闭数据库
sqlCon.close();
%>