基于java的登录验证系统（JSP）使用Sql数据库

package Servlet; import java.io.*; import java.sql.*; import javax.servlet.RequestDispatcher; import javax.servlet.ServletException; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class login_1 extends HttpServlet { private static final String CONTENT_TYPE = "text/html;charset = GB2312"; public login_1() { super(); } public void destroy() { super.destroy(); // Just puts "destroy" string in log // Put your code here } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException,IOException{ response.setContentType(CONTENT_TYPE); PrintWriter out = response.getWriter(); if(request.getParameter("username")!=null &&request.getParameter("password")!=null){ String username = request.getParameter("username"); String password = request.getParameter("password"); String displayWord = null; try{ Connection conn; Statement stmt; String url = "jdbc:sqlserver://127.0.0.1:1433;databaseName=Libdate"; String classforname = "com.microsoft.sqlserver.jdbc.SQLServerDriver"; String uid = "sa"; String pwd = "123456"; Class.forName(classforname); conn = DriverManager.getConnection( url, uid, pwd); stmt=conn.createStatement(); ResultSet rs1=null; rs1 = stmt.executeQuery("select * from Userdate where Username = '"+username+"'"); if(rs1!=null){ rs1.next(); String Dateus=rs1.getString("Upassword").toString().trim(); if(Dateus.equals(password)){//密码对了 displayWord="../index.jsp"; RequestDispatcher rs = request.getRequestDispatcher(displayWord); rs.forward(request, response); } else{//密码不对 displayWord="../jsp_cs1.jsp?a=y"; response.sendRedirect(displayWord); } } }catch(SQLException e) {//查找不到 displayWord="../jsp_cs1.jsp?a=n"; response.sendRedirect(displayWord); } catch(ClassNotFoundException e){//连接错误 //displayWord=" <font color=red>22ssss</font>!!!"; } //out.println(displayWord); } else{ out.println("back"); } } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } public void init() throws ServletException { // Put your code here } }