数据库用的是MySQL。
最近在学servlet，顺便把代码共享下。
这个servlet程序主要功能是，通过数据库查找验证用户，以及进行简单的管理，如添加、删除。
Login.java
1 package com.bai; 2 3 import javax.servlet.http.*; 4 import java.util.Date; 5 import java.text.DateFormat; 6 import java.text.SimpleDateFormat; 7 import java.net.*; 8 import java.io.*; 9 10 public class Login extends HttpServlet{11 12 public void doGet(HttpServletRequest req,HttpServletResponse res){13 14 //-------------------------------------------------------------------------------- 15 try{ 16 String ip=req.getRemoteAddr(); 17 this.getServletContext().setAttribute("ip",ip);18 19 FileWriter fw=new FileWriter("d://ip.txt",true);20 BufferedWriter bw=new BufferedWriter(fw);21 //获取当前时间22 Date dt=new Date();//如果不需要格式,可直接用dt,dt就是当前系统时间23 DateFormat df = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");//设置显示格式24 String nowTime="";25 nowTime= df.format(dt);//用DateFormat的format()方法在dt中获取并以yyyy/MM/dd HH:mm:ss格式显示26 27 //在文件中写入数据28 bw.write(""+this.getServletContext().getAttribute("ip")+" "+nowTime+"/r/n");29 //关闭文件流30 bw.close();31 }catch(Exception e){32 e.PRintStackTrace();33 }34 //----------------------------------------------------------- 35 try{req.setCharacterEncoding("gb2312");36 res.setContentType("text/html;charset=gb2312");37 PrintWriter pw=res.getWriter();38 pw.println("<html>");39 pw.println("<body bgcolor=#CACCF6>");40 pw.println("<center><img src='./imgs/imgs.jpg'/><hr>");41 pw.println("<h1>登陆界面</h1>");42 pw.println("<form action=logincl method=post>"); //跳转到logincl43 pw.println("用户名:<input type=text name=username><br>");44 pw.println("密码:<input type=passWord name=passwd><br>");45 pw.println("<input type=checkbox name=keep value=2>两周内不再重新登陆<br>");46 pw.println("<input type=submit value=login><br>");47 pw.println("</form>");48 pw.println("</center><img src='./imgs/logo.jpg'/><hr>");49 pw.println("</body>");50 pw.println("</html>");51 }52 catch(Exception e){53 e.printStackTrace();54 }55 }56 57 public void doPost(HttpServletRequest req,HttpServletResponse res){58 this.doGet(req,res);59 }60 }View CodeLoginCl.java
1 package com.bai; 2 3 import javax.servlet.http.*; 4 5 import java.io.*; 6 import java.sql.*; 7 8 public class LoginCl extends HttpServlet{ 9 10 //重写init()函数11 public void init(){12 try{13 //创建一个FileReader14 FileReader fr=new FileReader("d://myCounter.txt");15 BufferedReader br=new BufferedReader(fr);16 17 //读取一行18 String numVal=br.readLine();19 br.close();20 21 //将times值放入到servletContext中22 this.getServletContext().setAttribute("visitTimes",numVal);23 }catch(Exception e){24 e.printStackTrace();25 }26 }27 28 //重写destroy函数29 public void destroy(){30 try{31 //创建一个FileWriter,内存->磁盘,写入，输出32 FileWriter fw=new FileWriter("d://myCounter.txt");33 BufferedWriter bw=new BufferedWriter(fw);34 35 //在文件中写入数据36 bw.write(""+this.getServletContext().getAttribute("visitTimes"));37 //关闭文件流38 bw.close();39 }catch(Exception e){40 e.printStackTrace();41 }42 }43 public void doGet(HttpServletRequest req,HttpServletResponse res){44 45 Connection conn=null;46 Statement stmt=null;47 ResultSet rs=null;48 UserBeanCl ubc=null;49 // String sql = "select username,passwd from users where username = ? and passwd = ?";50 String sql = "select passwd from users where username = ? limit 1";51 try{//req.setCharacterEncoding("gb2312");52 String user=req.getParameter("username");53 String password=req.getParameter("passwd");54 55 //调用UserBeanCl56 ubc=new UserBeanCl();57 if(ubc.checkUser(user,password))58 { 59 Httpsession hs=req.getSession(true);60 hs.setMaxInactiveInterval(60);61 hs.setAttribute("name",user);62 hs.setAttribute("pass",password);63 64 String keep=req.getParameter("keep");65 if(keep!=null){66 67 Cookie name=new Cookie("myname",user);68 Cookie pass=new Cookie("mypass",password);69 name.setMaxAge(14*24*3600);70 pass.setMaxAge(14*24*3600);71 72 res.addCookie(name);73 res.addCookie(pass);74 }75 76 //将servletContext中的visitTimes所对应的值+177 String times=this.getServletContext().getAttribute("visitTimes").toString();78 //对times的值++然后写回到servletContext79 this.getServletContext().setAttribute("visitTimes",(Integer.parseInt(times)+1)+"");80 81 res.sendRedirect("main");82 //res.sendRedirect("welcome?&uname="+user+"&upass="+password); 83 }84 else{85 res.sendRedirect("login"); //url86 }87 88 }89 catch(Exception e){90 e.printStackTrace();91 }finally{92 ubc.close();93 }94 }95 96 public void doPost(HttpServletRequest req,HttpServletResponse res){97 this.doGet(req,res);98 }99 }View CodeMainFrame.java
1 package com.bai; 2 3 import javax.servlet.http.*; 4 5 import java.io.*; 6 7 public class MainFrame extends HttpServlet{ 8 public void doGet(HttpServletRequest req,HttpServletResponse res){ 9 try{req.setCharacterEncoding("gb2312");10 res.setContentType("text/html;charset=gb2312");11 PrintWriter pw=res.getWriter();12 pw.println("<html>");13 pw.println("<body bgcolor=#CACCF6>");14 pw.println("<center><img src='./imgs/imgs.jpg'/><hr>");15 pw.println("<h1>主界面</h1>");16 pw.println("<a href=welcome>管理用户</a>");17 pw.println("<a href=adduser>添加用户</a>");18 pw.println("<a href=check>查询用户</a>");19 pw.println("<a href=login>安全退出</a>");20 pw.println("</center><img src='./imgs/logo.jpg'/><hr>");21 pw.println("</body>");22 pw.println("</html>");23 }24 catch(Exception e){25 e.printStackTrace();26 }27 }28 29 public void doPost(HttpServletRequest req,HttpServletResponse res){30 this.doGet(req,res);31 }32 }View CodeWelcome.java
1 package com.bai; 2 3 import javax.servlet.http.*; 4 5 import java.io.*; 6 import java.sql.*; 7 import java.util.ArrayList; 8 9 public class Welcome extends HttpServlet{ 10 public void doGet(HttpServletRequest req,HttpServletResponse res){ 11 Connection conn=null; 12 Statement stmt=null; 13 ResultSet rs=null; 14 String u=null; 15 String p=null; 16 17 res.setContentType("text/html;charset=gb2312"); 18 HttpSession hs=req.getSession(); 19 String val=(String)hs.getAttribute("pass"); 20 21 Cookie []allCookies=req.getCookies(); 22 if(val==null){ 23 try{ 24 for(int i=0;i<allCookies.length;i++){ 25 26 if(allCookies[i].getName().equals("myname")) 27 u=allCookies[i].getValue(); 28 29 else if(allCookies[i].getName().equals("mypass")) 30 p=allCookies[i].getValue(); 31 } 32 if(u!=null&&p!=null){ 33 // hs.setAttribute("pass",p); 34 // res.sendRedirect("welcome?&uname="+u+"&upass="+p); 35 res.sendRedirect("logincl?username="+u+"&passwd="+p); 36 return ; 37 } 38 39 res.sendRedirect("login"); 40 return ; 41 }catch(Exception e){ 42 e.printStackTrace(); 43 } 44 45 } 46 47 u=req.getParameter("uname"); 48 p=req.getParameter("upass"); 49 50 try{//req.setCharacterEncoding("gb2312"); 51 52 int pageSize=5;//每一页显示记录数 53 int pageNow=1; //当前页 54 55 //动态接收pageNow 56 String sPageNow=req.getParameter("pageNow"); 57 if(sPageNow!=null){ 58 pageNow=Integer.parseInt(sPageNow); 59 } 60 61 //调用UserBeanCl 62 UserBeanCl ubc=new UserBeanCl(); 63 ArrayList al=ubc.getResultByPage(pageNow,pageSize); 64 65 PrintWriter pw=res.getWriter(); 66 67 pw.println("<body><center>"); 68 pw.println("<body bgcolor=#CACCF6>"); 69 pw.println("<img src='./imgs/imgs.jpg'/>"); 70 pw.println("<h1>管理用户</h1>"); 71 pw.println("<table border=1>");//带边框的表格 72 pw.println("<tr><th>id</th><th>name</th><th>password</th><th>email</th><th>grade</th><th>修改用户</th><th>删除用户</th></tr>");//表头 73 for(int i=0;i<al.size();i++){ 74 UserBean ub=(UserBean)al.get(i); 75 pw.println("<tr>"); 76 pw.println("<td>"+ub.getUserId()+"</td>"); 77 pw.println("<td>"+ub.getUserName()+"</td>"); 78 pw.println("<td>"+ub.getPasswd()+"</td>"); 79 pw.println("<td>"+ub.getEmail()+"</td>"); 80 pw.println("<td>"+ub.getGrade()+"</td>"); 81 pw.println("<td><a href=update?uId="+ub.getUserId()+"&uName="+ub.getUserName()+"&uPass="+ub.getPasswd()+"&uMail="+ub.getEmail()+"&uGrade="+ub.getGrade()+">修改用户</a></td>"); 82 pw.println("<td><a href=delete?userid="+ub.getUserId()+" onclick=/"return window.confirm('你确认要删除该用户吗？')/">删除用户</a></td>"); 83 pw.println("</tr>"); 84 } 85 pw.println("</table>"); 86 // res.setContentType("text/html;charset=gb2312"); 87 int pageCount=ubc.getPageCount(); 88 if(pageNow!=1) 89 pw.println("<a href=welcome?pageNow="+(pageNow-1)+"&uname="+u+"&upass="+p+">"+"last"+"</a>"); 90 91 for(int i=pageNow;i<=pageNow+4;i++){ 92 pw.println("<a href=welcome?pageNow="+i+"&uname="+u+"&upass="+p+">"+i+"</a>"); 93 } 94 if(pageNow!=pageCount) 95 pw.println("<a href=welcome?pageNow="+(pageNow+1)+"&uname="+u+"&upass="+p+">"+"next"+"</a>"); 96 97 //跳转功能 98 pw.println("<form action=welcome method=post>"); 99 pw.println("Go to<input type=text name=pageNow>page<br>");100 pw.println("<input type=submit value=Go><br>");101 102 // pw.println("<img src='./imgs/imgs.jpg'/>");103 // pw.println("welcome! "+u+"&pass="+p);104 pw.println("该网页被访问了"+this.getServletContext().getAttribute("visitTimes").toString()+"次");105 pw.println("你的IP："+req.getRemoteAddr()+"<br>");106 pw.println("你的机器名="+req.getRemoteHost()+"<br>");107 pw.println("</center><img src='./imgs/logo.jpg'/><hr>");108 pw.println("</body>");109 }110 catch(Exception e){111 e.printStackTrace();112 }finally{113 114 }115 }116 public void doPost(HttpServletRequest req,HttpServletResponse res){117 this.doGet(req,res);118 }119 }View CodeUserBeanCl.java
1 //处理users表的类,操作userbean 2 //业务逻辑 3 package com.bai; 4 import java.sql.*; 5 import java.util.ArrayList; 6 public class UserBeanCl{ 7 //业务逻辑 8 private Connection conn=null; 9 private PreparedStatement ps=null; 10 private ResultSet rs=null; 11 private int rowCount=0;//共有几条记录 12 private int pageCount=0;//共有几页 13 14 //查询用户 15 public ArrayList Check(String querytype,String username){ 16 ArrayList al=new ArrayList(); 17 try{ 18 //得到连接 19 ConnDB cd=new ConnDB(); 20 conn=cd.getConn(); 21 Statement stmt = conn.createStatement(); 22 if(querytype.equals("fuzzy")){ //模糊查询 23 //模糊查询算法 24 char arr[]=username.toCharArray(); 25 String sql="select * from users where "; 26 for(int i=0;i<username.length();i++){ 27 if(i==0) 28 sql=sql.concat("upper(username) like '%"+arr[i]+"%' "); 29 else sql=sql.concat("and upper(username) like '%"+arr[i]+"%' "); 30 } 31 System.out.println(sql); 32 rs=stmt.executeQuery(sql); 33 34 } 35 if(querytype.equals("precise")){ //精确查询 36 ps=conn.prepareStatement("select * from users where username=?"); 37 ps.setString(1,username); 38 rs=ps.executeQuery(); 39 System.out.println(ps); 40 //String sql1=("select * from users where username="); 41 //sql1=sql1.concat(username); 42 //System.out.println(sql1); 43 //rs=stmt.executeQuery(sql1); 44 } 45 while(rs.next()){ 46 //将rs中每条记录封装到userbean中 47 UserBean ub=new UserBean(); 48 ub.setUserId(rs.getInt(1)); 49 ub.setUserName(rs.getString(2)); 50 ub.setPasswd(rs.getString(3)); 51 ub.setEmail(rs.getString(4)); 52 ub.setGrade(rs.getInt(5)); 53 54 //将ub放入到ArrayList中 55 al.add(ub); 56 } 57 }catch(Exception e){ 58 e.printStackTrace(); 59 }finally{ 60 this.close(); 61 } 62 return al; 63 } 64 65 //添加用户 66 public boolean AddUser(String id,String username,String email,String passwd,String grade){ 67 try{ 68 //得到连接 69 ConnDB cd=new ConnDB(); 70 conn=cd.getConn(); 71 72 ps=conn.prepareStatement("insert into users(userId,username,passwd,email,grade) values(?,?,?,?,?)"); 73 ps.setString(1,id); 74 ps.setString(2,username); 75 ps.setString(3,email); 76 ps.setString(4,passwd); 77 ps.setString(5,grade); 78 79 int num=ps.executeUpdate(); 80 if(num==1){ 81 return true; 82 } 83 84 }catch(Exception e){ 85 e.printStackTrace(); 86 }finally{ 87 this.close(); 88 } 89 return false; 90 } 91 92 //修改用户 93 public boolean UpdateUser(String id,String email,String passwd,String grade){ 94 try{ 95 //得到连接 96 ConnDB cd=new ConnDB(); 97 conn=cd.getConn(); 98 99 ps=conn.prepareStatement("update users set email=?,passwd=?,grade=? where userId=?");100 ps.setString(1,email);101 ps.setString(2,passwd);102 ps.setString(3,grade);103 ps.setString(4,id);104 int num=ps.executeUpdate();105 if(num==1){106 return true;107 }108 109 }catch(Exception e){110 e.printStackTrace();111 }finally{112 this.close();113 }114 return false;115 }116 117 //删除用户118 public boolean deleteUser(String id){119 try{120 //得到连接121 ConnDB cd=new ConnDB();122 conn=cd.getConn();123 124 ps=conn.prepareStatement("delete from users where userId=?");125 ps.setString(1,id);126 int num=ps.executeUpdate();127 if(num==1){128 return true;129 }130 131 }catch(Exception e){132 e.printStackTrace();133 }finally{134 this.close();135 }136 return false;137 }138 139 //返回pageCount140 public int getPageCount(){141 return this.pageCount;142 }143 //分页显示144 public ArrayList getResultByPage(int pageNow,int pageSize){145 146 ArrayList al=new ArrayList();147 try{148 149 ConnDB cd=new ConnDB();150 conn=cd.getConn();151 ps=conn.prepareStatement("select count(*) from users");152 rs=ps.executeQuery();153 //得到行数154 if(rs.next()){155 rowCount = rs.getInt(1);156 }157 //计算页数158 if(rowCount%pageSize==0){159 pageCount=rowCount/pageSize;160 }else{161 pageCount=rowCount/pageSize+1;162 }163 String sql="select * from users where userId not in(select * from(select userId from users limit ?)a) limit ?";164 PreparedStatement pstmt = conn.prepareStatement(sql);165 pstmt.setInt(2,pageSize);166 pstmt.setInt(1,pageSize*(pageNow-1));167 rs=pstmt.executeQuery();168 169 while(rs.next()){170 //将rs中每条记录封装到userbean中171 UserBean ub=new UserBean();172 ub.setUserId(rs.getInt(1));173 ub.setUserName(rs.getString(2));174 ub.setPasswd(rs.getString(3));175 ub.setEmail(rs.getString(4));176 ub.setGrade(rs.getInt(5));177 178 //奖ub放入到ArrayList中179 al.add(ub);180 }181 }catch(Exception e){182 e.printStackTrace();183 }finally{184 this.close();185 }186 return al;187 }188 189 //验证用户190 public boolean checkUser(String u,String p){191 boolean b=false;192 try{193 //得到连接194 ConnDB cd=new ConnDB();195 conn=cd.getConn();196 197 ps=conn.prepareStatement("select passwd from users where username = ? limit 1");198 ps.setString(1,u);199 rs=ps.executeQuery();200 201 if(rs.next()){ 202 String dbPasswd=rs.getString(1);203 if(dbPasswd.equals(p)) {204 b=true;205 }206 } 207 }catch(Exception e){208 e.printStackTrace();209 }finally{210 this.close();211 }212 return b;213 }214 215 //关闭数据库连接216 public void close(){217 try{218 if(rs!=null){219 rs.close();220 rs=null;221 }222 if(ps!=null){223 ps.close();224 ps=null;225 }226 if(conn!=null){227 conn.close();228 conn=null;229 }230 }catch(Exception e){231 e.printStackTrace();232 }233 }234 }View CodeConnDB.java //获取数据库连接
1 //g从数据库得到连接 2 3 package com.bai; 4 import java.sql.*; 5 6 public class ConnDB{ 7 private Connection conn=null; 8 public Connection getConn(){ 9 try{10 //加载驱动11 Class.forName("com.mysql.jdbc.Driver");12 //得到连接13 conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/sqdb","root","root");14 }catch(Exception e){15 e.printStackTrace();16 }17 return conn;18 }19 }View CodeUserBean.java
1 package com.bai; 2 3 public class UserBean{ 4 private int userId; 5 private String userName; 6 private String passwd; 7 private String email; 8 private int grade; 9 10 public void setUserId(int userId){11 this.userId=userId;12 }13 public int getUserId(){14 return (this.userId);15 }16 17 18 public void setEmail(String email) {19 this.email = email; 20 }21 22 public String getEmail() {23 return (this.email); 24 }25 26 27 public void setUserName(String userName) {28 this.userName = userName; 29 }30 31 public void setPasswd(String passwd) {32 this.passwd = passwd; 33 }34 35 public void setGrade(int grade) {36 this.grade = grade; 37 }38 39 public String getUserName() {40 return (this.userName); 41 }42 43 public String getPasswd() {44 return (this.passwd); 45 }46 47 public int getGrade() {48 return (this.grade); 49 }50 }View CodeUpdate.java
1 package com.bai; 2 3 import javax.servlet.http.*; 4 5 import java.io.*; 6 7 public class Update extends HttpServlet{ 8 9 public void doGet(HttpServletRequest req,HttpServletResponse res){10 11 12 try{req.setCharacterEncoding("gb2312");13 res.setContentType("text/html;charset=gb2312");14 PrintWriter pw=res.getWriter();15 pw.println("<html>");16 pw.println("<body bgcolor=#CACCF6>");17 pw.println("<center><img src='./imgs/imgs.jpg'/><hr>");18 19 pw.println("<h1>修改用户界面</h1>");20 pw.println("<form action=updatecl>");21 pw.println("<table border=1>");22 23 pw.println("<tr><td>id</td><td><input readonly name=userid type=text value="+req.getParameter("uId")+"></td></tr>");24 pw.println("<tr><td>name</td><td><input readonly type=text value="+req.getParameter("uName")+"></td></tr>");25 pw.println("<tr><td>passwd</td><td><input type=text name=newPass value="+req.getParameter("uPass")+"></td></tr>");26 pw.println("<tr><td>email</td><td><input type=text name=newEmail value="+req.getParameter("uMail")+"></td></tr>");27 pw.println("<tr><td>grade</td><td><input type=text name=newGrade value="+req.getParameter("uGrade")+"></td></tr>");28 pw.println("<tr><td colspan=2><input type=submit value=修改用户></td></tr>");29 pw.println("</table></form>");30 31 pw.println("</center><img src='./imgs/logo.jpg'/><hr>");32 pw.println("</body>");33 pw.println("</html>");34 }35 catch(Exception e){36 e.printStackTrace();37 }38 }39 40 public void doPost(HttpServletRequest req,HttpServletResponse res){41 this.doGet(req,res);42 }43 }View CodeUpdateCl.java
1 package com.bai; 2 3 import javax.servlet.http.*; 4 5 import java.io.*; 6 7 public class UpdateCl extends HttpServlet{ 8 public void doGet(HttpServletRequest req,HttpServletResponse res){ 9 try{10 res.setContentType("text/html;charset=gbk");11 12 UserBeanCl ubc=new UserBeanCl();13 14 if(ubc.UpdateUser(req.getParameter("userid"),req.getParameter("newEmail"),req.getParameter("newPass"),req.getParameter("newGrade"))){15 //删除成功16 res.sendRedirect("ok");17 }else{18 //删除失败19 res.sendRedirect("err");20 }21 }22 catch(Exception e){23 e.printStackTrace();24 }25 }26 27 public void doPost(HttpServletRequest req,HttpServletResponse res){28 this.doGet(req,res);29 }30 }View CodeAddUser.java
1 package com.bai; 2 3 import javax.servlet.http.*; 4 5 import java.io.*; 6 7 public class AddUser extends HttpServlet{ 8 9 public void doGet(HttpServletRequest req,HttpServletResponse res){10 11 12 try{req.setCharacterEncoding("gb2312");13 res.setContentType("text/html;charset=gb2312");14 PrintWriter pw=res.getWriter();15 pw.println("<html>");16 pw.println("<body bgcolor=#CACCF6>");17 pw.println("<center><img src='./imgs/imgs.jpg'/><hr>");18 19 pw.println("<h1>添加用户界面</h1>");20 pw.println("<form action=addusercl method=post>");21 22 pw.println("用户id:<input type=text name=userid><br>");23 pw.println("用户名:<input type=text name=username><br>");24 pw.println("密 码:<input type=password name=passwd><br>");25 pw.println("邮 箱:<input type=text name=email><br>");26 pw.println("等 级:<input type=text name=grade><br>");27 28 pw.println("<input type=submit value=添加><br>");29 pw.println("</form>");30 31 pw.println("</center><img src='./imgs/logo.jpg'/><hr>");32 pw.println("</body>");33 pw.println("</html>");34 }35 catch(Exception e){36 e.printStackTrace();37 }38 }39 40 public void doPost(HttpServletRequest req,HttpServletResponse res){41 this.doGet(req,res);42 }43 }View CodeAddUserCl.java
1 package com.bai; 2 3 import javax.servlet.http.*; 4 5 import java.io.*; 6 7 public class AddUserCl extends HttpServlet{ 8 public void doGet(HttpServletRequest req,HttpServletResponse res){ 9 try{10 res.setContentType("text/html;charset=gbk");11 12 UserBeanCl ubc=new UserBeanCl();13 14 if(ubc.AddUser(req.getParameter("userid"),req.getParameter("username"),req.getParameter("email"),req.getParameter("passwd"),req.getParameter("grade"))){15 //删除成功16 res.sendRedirect("ok");17 }else{18 //删除失败19 res.sendRedirect("err");20 }21 }22 catch(Exception e){23 e.printStackTrace();24 }25 }26 27 public void doPost(HttpServletRequest req,HttpServletResponse res){28 this.doGet(req,res);29 }30 }View CodeDeleteUser.java
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