JSP+MYsql 登入代码，查询，修改，删除代码

package com.zeng.servlet; import java.io.IOException; import java.io.PrintWriter; import java.sql.*; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.zeng.databean.*; public class Jregiter extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setCharacterEncoding("gb2312"); response.setContentType("text/html;charset=gb2312"); PrintWriter out = response.getWriter(); String name=request.getParameter("name"); //获取form中输入的数据 name=new String(name.getBytes("ISO-8859-1"),"gb2312"); String pwd=request.getParameter("pwd"); String sex=request.getParameter("sex"); sex=new String(sex.getBytes("ISO-8859-1"),"gb2312"); String age=request.getParameter("age"); String city=request.getParameter("city"); city=new String(city.getBytes("ISO-8859-1"),"gb2312"); if(name==""||pwd==""||sex==""||age==""||city=="") { response.sendRedirect("Rall.jsp"); } else { try { String Tsql="insert into tbl_user(name,pwd,sex,age,city) values ('"+name+"','"+pwd+"','"+sex+"',"+age+",'"+city+"')"; String sql="select * from tbl_user where name="+name+""; mysqlconn cn= new mysqlconn(); //定义数据库连接 Connection conn=cn.getConn(); ResultSet rs=cn.executeSQL(sql); rs.last(); int rowcount=rs.getRow(); if(rowcount>0){ response.sendRedirect("Ragain.jsp"); } else{ cn.executeUpdate(Tsql); //插入数据 response.sendRedirect("Rsuc.jsp"); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } public void init() throws ServletException { // Put your code here } }