javaweb+mysql编写得登录页面

package com.servlet; import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.ArrayList; import java.util.List; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.bean.Admin; import com.util.DBUtil; public class AdminServlet extends HttpServlet { /** * Constructor of the object. */ public AdminServlet() { super(); } /** * Destruction of the servlet. <br> */ public void destroy() { super.destroy(); // Just puts "destroy" string in log // Put your code here } /** * The doGet method of the servlet. <br> * * This method is called when a form has its tag value method equals to get. * * @param request * the request send by the client to the server * @param response * the response send by the server to the client * @throws ServletException * if an error occurred * @throws IOException * if an error occurred */ public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } /** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to * post. * * @param request * the request send by the client to the server * @param response * the response send by the server to the client * @throws ServletException * if an error occurred * @throws IOException * if an error occurred */ public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); String mode = request.getParameter("mode"); String pageNoStr = request.getParameter("pageNoStr") == null ? "1" : request.getParameter("pageNoStr"); int m = 0; int n = 2;// 每页大小 int totle = 0; int pageNo = Integer.parseInt(pageNoStr); if (pageNo == 1) {// 首页 } else { m = (pageNo - 1) * n; } DBUtil util = new DBUtil(); Connection conn = util.openConnection(); try { if (mode != null && mode.equals("list")) { String sql = " select * from admins limit "+m+","+n; String sql2 = "select count(*) from admins "; PreparedStatement pstmt1 = conn.prepareStatement(sql); PreparedStatement pstmt2 = conn.prepareStatement(sql2); ResultSet rs = pstmt1.executeQuery(); ResultSet rs2 = pstmt2.executeQuery(); rs2.next(); totle = rs2.getInt(1); int totlePage = totle / n; int totlePageY = totle % n; if (totlePageY != 0) { totlePage = totlePage + 1; } List<Admin> list = new ArrayList<Admin>(); while (rs.next()) { Admin bean = new Admin(); bean.setId(rs.getInt("id")); bean.setUsername(rs.getString("username")); bean.setPassword(rs.getString("password")); list.add(bean); } request.setAttribute("list", list); System.out.println("!!!!!!!!!!!!!!!!!!!!!!!"); request.getRequestDispatcher("adminlist.jsp").forward(request, response); } if (mode != null && mode.equals("add")) { String username = request.getParameter("username"); String password = request.getParameter("password"); String sqlAdd = "insert into admins(username,password) values('" + username + "','" + password + "')"; Statement stmt = conn.createStatement(); stmt.executeUpdate(sqlAdd); request.setAttribute("ok", "ok"); request.getRequestDispatcher("add.jsp").forward(request, response); } if (mode != null && mode.equals("modifybefore")) { String id = request.getParameter("id"); String sql = "select * from admins where id=" + id; PreparedStatement pstmt = conn.prepareStatement(sql); ResultSet rs = pstmt.executeQuery(); Admin bean = new Admin(); while (rs.next()) { bean.setId(rs.getInt("id")); bean.setUsername(rs.getString("username")); bean.setPassword(rs.getString("password")); break; } request.setAttribute("bean", bean); request.getRequestDispatcher("adminmodify.jsp").forward( request, response); } if (mode != null && mode.equals("modify")) { String id = request.getParameter("id"); String password = request.getParameter("password"); String sqlUpdate = "update admins set password='" + password + "' where id=" + id; Statement stmt = conn.createStatement(); stmt.executeUpdate(sqlUpdate); String sql = " select * from admins limit "+m+","+n; String sql2 = "select count(*) from admins "; PreparedStatement pstmt1 = conn.prepareStatement(sql); PreparedStatement pstmt2 = conn.prepareStatement(sql2); ResultSet rs = pstmt1.executeQuery(); ResultSet rs2 = pstmt2.executeQuery(); rs2.next(); totle = rs2.getInt(1); int totlePage = totle / n; int totlePageY = totle % n; if (totlePageY != 0) { totlePage = totlePage + 1; } List<Admin> list = new ArrayList<Admin>(); while (rs.next()) { Admin bean = new Admin(); bean.setId(rs.getInt("id")); bean.setUsername(rs.getString("username")); bean.setPassword(rs.getString("password")); list.add(bean); } request.setAttribute("list", list); request.getRequestDispatcher("adminlist.jsp").forward(request, response); } if (mode != null && mode.equals("deletes")) { String[] selectFlag = request.getParameterValues("selectFlag"); for (int i = 0; i < selectFlag.length; i++) { String sql = "delete from admins where id=" + selectFlag[i]; Statement stmt = conn.createStatement(); stmt.executeUpdate(sql); } String sql = " select * from admins limit "+m+","+n; String sql2 = "select count(*) from admins "; PreparedStatement pstmt1 = conn.prepareStatement(sql); PreparedStatement pstmt2 = conn.prepareStatement(sql2); ResultSet rs = pstmt1.executeQuery(); ResultSet rs2 = pstmt2.executeQuery(); rs2.next(); totle = rs2.getInt(1); int totlePage = totle / n; int totlePageY = totle % n; if (totlePageY != 0) { totlePage = totlePage + 1; } List<Admin> list = new ArrayList<Admin>(); while (rs.next()) { Admin bean = new Admin(); bean.setId(rs.getInt("id")); bean.setUsername(rs.getString("username")); bean.setPassword(rs.getString("password")); list.add(bean); } request.setAttribute("list", list); request.getRequestDispatcher("adminlist.jsp").forward(request, response); } } catch (SQLException e) { e.printStackTrace(); } finally { util.closeConn(conn); } } /** * Initialization of the servlet. <br> * * @throws ServletException * if an error occurs */ public void init() throws ServletException { // Put your code here } }