Servlet教程第7讲笔记

(一）美化管理系统界面
（二）管理系统功能改善，增删改查

(一）美化管理系统界面
推荐得到颜色配置的软件playcolor和AAA logo

增删改查

//登录界面
package com.tingwei;
import javax.servlet.http.*;
import java.io.*;
public class Login extends HttpServlet{public void doGet(HttpServletRequest req,HttpServletResponse res){try {//中文乱码处理res.setContentType("text/html;charset=gbk");PrintWriter pw=res.getWriter();//返回登录界面pw.println("<html>");pw.println("<body bgcolor=#B4CDE6>");pw.println("<img src=imgs/image2.jpg width=200><hr><center>");pw.println("<h>登录界面</h>");pw.println("<form action=logincl method=post>");pw.println("用户名:<input type=text name=username><br>");pw.println("密码:<input type=password name=passwd><br>");pw.println("<input type=checkbox name=keep value=2>两周内不在重新登录<br>");pw.println("<input type=submit value=login><br>");pw.println("</form>");pw.println("</center><hr><img src=imgs/image2.jpg width=200>");pw.println("</body>");pw.println("</html>");} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}public void doPost(HttpServletRequest req,HttpServletResponse res){this.doGet(req, res);}
}

//用户验证Servlet
package com.tingwei;
import javax.servlet.http.*;import java.io.*;
import java.sql.*;
public class LoginCl extends HttpServlet{//重写init函数public void init(){//只会被调用一次try {//创建一个FileReaderFileReader fr=new FileReader("f:\\myCounter.txt");BufferedReader br=new BufferedReader(fr);String numVal=br.readLine();br.close();//将times值放入servletContext中this.getServletContext().setAttribute("visitTimes", numVal+"");System.out.println("init()被调用");} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}//重写destroy函数public void destroy(){try {FileWriter fw=new FileWriter("f:\\myCounter.txt");BufferedWriter bw=new BufferedWriter(fw);bw.write(this.getServletContext().getAttribute("visitTimes").toString());bw.close();System.out.println("destroy()被调用");} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}public void doGet(HttpServletRequest req,HttpServletResponse res){ //业务逻辑try {//接收用户名和密码String u=req.getParameter("username");String p=req.getParameter("passwd");//调用UserBeanCl,1.创建对象，2.使用方法UserBeanCl ubc=new UserBeanCl();//验证if(ubc.checkUser(u, p)){//合法用户String keep=req.getParameter("keep");//将用户名和密码保存在客户端cookieif(keep!=null){Cookie name=new Cookie("myname",u);Cookie pass=new Cookie("mypasswd",p);//设置时间name.setMaxAge(14*24*3600);pass.setMaxAge(14*24*3600);//回写到客户端res.addCookie(name);res.addCookie(pass);}//将验证成功的信息写入sessionHttpSession hs=req.getSession(true);//修改session的存在时间 单位shs.setMaxInactiveInterval(30);hs.setAttribute("uname", u);//将servletContext中的visitTimes所对应的值增加String times=this.getServletContext().getAttribute("visitTimes").toString();//对times++再重新放回servletContextthis.getServletContext().setAttribute("visitTimes", (Integer.parseInt(times)+1)+"");res.sendRedirect("main");}else{//不合法，跳转到Loginres.sendRedirect("login");}} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}public void doPost(HttpServletRequest req,HttpServletResponse res){this.doGet(req, res);}
}

//主界面
package com.tingwei;
import javax.servlet.http.*;
import java.io.*;
public class Main extends HttpServlet{public void doGet(HttpServletRequest req,HttpServletResponse res){try {//中文乱码处理res.setContentType("text/html;charset=gbk");PrintWriter pw=res.getWriter();//返回登录界面pw.println("<html>");pw.println("<body bgcolor=#B4CDE6>");pw.println("<img src=imgs/image2.jpg width=200><hr><center>");pw.println("<h1>主界面</h1>");pw.println("<a href=wel>管理用户</a><br>");pw.println("<a href=?>添加用户</a><br>");pw.println("<a href=?>查找用户</a><br>");pw.println("<a href=?>安全退出</a><br>");pw.println("</center><hr><img src=imgs/image2.jpg width=200>");pw.println("</body>");pw.println("</html>");} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}public void doPost(HttpServletRequest req,HttpServletResponse res){this.doGet(req, res);}
}

//管理界面
package com.tingwei;
import javax.servlet.http.*;import java.io.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
public class Wel extends HttpServlet{public void doGet(HttpServletRequest req,HttpServletResponse res){//得到sessionHttpSession hs=req.getSession();String myName=(String)hs.getAttribute("uname");String name="";String password="";PrintWriter pw=null;Connection ct=null;PreparedStatement ps=null;ResultSet rs=null;String url="jdbc:microsoft:sqlserver://127.0.0.1:1433;databaseName=spdb";String user="sa";String passwd="tingwei";String driver="com.microsoft.jdbc.sqlserver.SQLServerDriver";try {//判断if(myName==null){//如果session中没有用户信息，再看看cookie中有没有Cookie [] allCookies=req.getCookies();int i=0;//如果allCookies不为空if(allCookies!=null){//从中取出cookiefor(i=0;i<allCookies.length;i++){//依次取出Cookie tmp=allCookies[i];if(tmp.getName().equals("myname")){//得到cookie信息name=tmp.getValue();}else if(tmp.getName().equals("pass")){password=tmp.getValue();}}//forif(!name.equals("")&&!password.equals("")){res.sendRedirect("logincl?username="+name+"&passwd="+password);}}//if cookie//返回登录界面res.sendRedirect("login?info=error1");}} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}//===分页的功能===int pageSize=3;int pageNow=1;//希望显示第几条记录//动态的接收pageNowString sPageNow=req.getParameter("pageNowOk");if(sPageNow!=null){//用户首次进入wel页面pageNow=Integer.parseInt(sPageNow);}//调用UserBeanClUserBeanCl ubc=new UserBeanCl();ArrayList al=ubc.getResultByPage(pageNow, pageSize);//得到从logincl传递的用户名String u=req.getParameter("uname");//得到从logincl传递的密码String p=req.getParameter("upass");try {//中文乱码处理res.setContentType("text/html;charset=gbk");pw=res.getWriter();    pw.println("<body><center>");pw.println("<img src=imgs/image2.jpg width=200>&nbsp;&nbsp;&nbsp;&nbsp;欢迎您："+myName+"<img src=imgs/image1.jpg width=50><br>");pw.println("<h1>管理用户</h1>");pw.println("welcome,hello "+u+" pass="+p);pw.println("<br><a href=login>返回重新登录</a>");pw.println("<table border=1>");pw.println("<tr bgcolor=blue><th>id</th><th>name</th><th>passwd</th><th>email</th><th>grade</th><th>修改用户</th><th>删除用户</th></tr>");//定义一个颜色数组String [] mycol={"pink","silver"};for(int i=0;i<al.size();i++){UserBean ub=(UserBean)al.get(i);pw.println("<tr bgcolor="+mycol[i%2]+">");pw.println("<td>"+ub.getUserId()+"</td>");pw.println("<td>"+ub.getUserName()+"</td>");pw.println("<td>"+ub.getPasswd()+"</td>");pw.println("<td>"+ub.getMial()+"</td>");pw.println("<td>"+ub.getGrade()+"</td>");pw.println("<td><a href=update?uId="+ub.getUserId()+"&uName="+ub.getUserName()+"&uPass="+ub.getPasswd()+"&uMail="+ub.getMial()+"&uGrade="+ub.getGrade()+">修改用户</a></td>");pw.println("<td><a href=delUserCl?userid="+ub.getUserId()+" οnclick=\"return window.confirm('您确认要删除该用户吗?')\">删除用户</a></td>");pw.println("</tr>");}pw.println("</table>");if(pageNow!=1)//上一页pw.println("<a href=wel?pageNowOk="+(pageNow-1)+">上一页</a>");//显示超链接for(int i=pageNow;i<=pageNow+4;i++){pw.println("<a href=wel?pageNowOk="+i+">"+i+"</a>");}int pageCount=ubc.getPageCount();//下一页if(pageNow!=pageCount)pw.println("<a href=wel?pageNowOk="+(pageNow+1)+">下一页</a>");//指定跳转到某一页，实际上是一个表单,输入的页数过大，输入的不是数值又怎么办？pw.println("<form action=wel>");pw.println("<input type=text name=pageNowOk>");pw.println("<input type=submit value=go>");pw.println("</form>");pw.println("<br>该网页被访问了"+this.getServletContext().getAttribute("visitTimes").toString()+"次");pw.println("<br>您的ip："+req.getRemoteAddr()+"<br>");pw.println("您的机器名："+req.getRemoteHost()+"<br>");pw.println("您的ip："+req.getRemoteAddr()+"<br>");pw.println("您的端口号："+req.getRemotePort()+"<br>");pw.println("</center></body>");} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}public void doPost(HttpServletRequest req,HttpServletResponse res){this.doGet(req, res);}
}

//从数据库得到连接
package com.tingwei;
import java.sql.*;
public class ConnDB {private Connection  ct=null;public Connection getConn(){try {String url="jdbc:microsoft:sqlserver://127.0.0.1:1433;databaseName=spdb";String user="sa";String passwd="tingwei";String driver="com.microsoft.jdbc.sqlserver.SQLServerDriver";//得到rowCount//连接接数据库，三部曲Class.forName(driver);//得到连接ct=DriverManager.getConnection(url,user,passwd);} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}return ct;}
}

//这是一个UserBean，和User表映射
//它的一个对象映射user表的一条记录
//数据
package com.tingwei;public class UserBean {private int userId;private String userName;private String passwd;private String mial;private int grade;public int getUserId() {return userId;}public void setUserId(int userId) {this.userId = userId;}public String getUserName() {return userName;}public void setUserName(String userName) {this.userName = userName;}public String getPasswd() {return passwd;}public void setPasswd(String passwd) {this.passwd = passwd;}public String getMial() {return mial;}public void setMial(String mial) {this.mial = mial;}public int getGrade() {return grade;}public void setGrade(int grade) {this.grade = grade;}}

//这是一个处理类（处理Users表）<--->操作userBean
//业务逻辑在这
package com.tingwei;
import java.sql.*;
import java.util.ArrayList;
public class UserBeanCl {//业务逻辑private Connection ct=null;private PreparedStatement ps=null;private ResultSet rs=null;private int pageCount=0;//共有几页（计算得到）//验证用户public boolean checkUser(String u,String p){boolean b=false;try {//得到连接ConnDB cd=new ConnDB();ct=cd.getConn();ps=ct.prepareStatement("select top 1 passwd from users where username=?");ps.setString(1, u);rs=ps.executeQuery();if(rs.next()){String dbPasswd=rs.getString(1);if(dbPasswd.equals(p)){b=true;}}} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}finally{//用完数据库后记得关闭，可以写一个函数来关this.close();}return b;}//关闭数据库public void close(){try {if(rs!=null)rs.close();if(ps!=null)ps.close();if(ct!=null)ct.close();} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}//分页显示public ArrayList getResultByPage(int pageNow,int pageSize){ArrayList al=new ArrayList();try {int rowCount=0;//共有几条记录（查表）int pageCount=0;//共有几页（计算出来）//得到rowCountConnDB cd=new ConnDB();ct=cd.getConn();//创建一个prepareStatementps=ct.prepareStatement("select count(*) from users");rs=ps.executeQuery(); //执行得到结果if(rs.next()){rowCount=rs.getInt(1);}//计算pageCountif(rowCount%pageSize==0){pageCount=rowCount/pageSize;}else{pageCount=rowCount/pageSize+1;}ps=ct.prepareStatement("select top "+pageSize+" * from users where userId not in(select top "+pageSize*(pageNow-1)+" userId from users)");//给？赋值rs=ps.executeQuery();while(rs.next()){//将rs中的每一条记录分装到UserBean ub中UserBean ub=new UserBean();ub.setUserId(rs.getInt(1));ub.setUserName(rs.getString(2));ub.setPasswd(rs.getString(3));ub.setMial(rs.getString(4));ub.setGrade(rs.getInt(5));//将ub放入到ArrayList中al.add(ub);}} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}finally{this.close();}return al;}//返回计算所得页数public int getPageCount(){return this.pageCount;}//删除用户public boolean delUser(String id){boolean b=false;try {ConnDB cd=new ConnDB();ct=cd.getConn();String sql="delete from users where userId='"+id+"'";ps=ct.prepareStatement(sql);int num=ps.executeUpdate();if(num==1){b=true;}} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}finally{this.close();return b;}}//修改用户public boolean updateUser(String id,String email,String passwd,String grade){boolean b=false;try {ConnDB cd=new ConnDB();ct=cd.getConn();String sql="update users set passwd='"+passwd+"',email='"+email+"',grade='"+grade+"' where userId='"+id+"'";ps=ct.prepareStatement(sql);int num=ps.executeUpdate();if(num==1){b=true; //修改成功}} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}finally{this.close();return b;}}
}

//处理删除用户
package com.tingwei;
import javax.servlet.http.*;
import java.io.*;
public class DelUserCl extends HttpServlet{public void doGet(HttpServletRequest req,HttpServletResponse res){try {//中文乱码处理res.setContentType("text/html;charset=gbk");//调用UserBeanCl中的删除用户的方法，完成删除UserBeanCl ubc=new UserBeanCl();//接收从wel传递的id号String id=req.getParameter("userid");if(ubc.delUser(id)){//删除成功res.sendRedirect("ok");}else{res.sendRedirect("err");}} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}public void doPost(HttpServletRequest req,HttpServletResponse res){this.doGet(req, res);}
}

//操作成功界面
package com.tingwei;
import javax.servlet.http.*;
import java.io.*;
public class Ok extends HttpServlet{public void doGet(HttpServletRequest req,HttpServletResponse res){try {//中文乱码处理res.setContentType("text/html;charset=gbk");PrintWriter pw=res.getWriter();pw.println("操作成功！<br>");pw.println("<a href=main>返回主界面</a>&nbsp;&nbsp;<a href=wel>继续删除</a>");} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}public void doPost(HttpServletRequest req,HttpServletResponse res){this.doGet(req, res);}
}

//操作失败界面
package com.tingwei;
import javax.servlet.http.*;
import java.io.*;
public class Err extends HttpServlet{public void doGet(HttpServletRequest req,HttpServletResponse res){try {//中文乱码处理res.setContentType("text/html;charset=gbk");PrintWriter pw=res.getWriter();pw.println("操作失败！");} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}public void doPost(HttpServletRequest req,HttpServletResponse res){this.doGet(req, res);}
}

//修改用户界面
package com.tingwei;
import javax.servlet.http.*;
import java.io.*;
public class Update extends HttpServlet{public void doGet(HttpServletRequest req,HttpServletResponse res){try {//中文乱码处理res.setContentType("text/html;charset=gbk");PrintWriter pw=res.getWriter();//返回登录界面pw.println("<html>");pw.println("<body bgcolor=#B4CDE6>");pw.println("<img src=imgs/image2.jpg width=200><hr><center>");pw.println("<h1>修改用户界面</h1>");pw.println("<form action=updateCl>");pw.println("<table border=1>");pw.println("<tr><td>id</td><td><input readonly name=uId type=text value="+req.getParameter("uId")+"></td></tr>");pw.println("<tr><td>username</td><td><input readonly type=text value="+req.getParameter("uName")+"></td></tr>");pw.println("<tr><td>passwd</td><td><input name=newPasswd type=text value="+req.getParameter("uPass")+"></td></tr>");pw.println("<tr><td>eamil</td><td><input name=newEmail type=text value="+req.getParameter("uMail")+"></td></tr>");pw.println("<tr><td>grade</td><td><input name=newGrade type=text value="+req.getParameter("uGrade")+"></td></tr>");pw.println("<tr><td colspan=2><input type=submit value=修改用户></td></tr>");pw.println("</table></form>");pw.println("</center><hr><img src=imgs/image2.jpg width=200>");pw.println("</body>");pw.println("</html>");} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}public void doPost(HttpServletRequest req,HttpServletResponse res){this.doGet(req, res);}
}

//处理修改用户
package com.tingwei;
import javax.servlet.http.*;
import java.io.*;
public class UpdateCl extends HttpServlet{public void doGet(HttpServletRequest req,HttpServletResponse res){try {//中文乱码处理res.setContentType("text/html;charset=gbk");//调用UserBeanCl中的删除用户的方法，完成删除UserBeanCl ubc=new UserBeanCl();//接收从update传递需要修改的信息String id=req.getParameter("uId");String email=req.getParameter("newEmail");String passwd=req.getParameter("newPasswd");String grade=req.getParameter("newGrade");if(ubc.updateUser(id, email, passwd, grade)){//删除成功res.sendRedirect("ok");}else{res.sendRedirect("err");}} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}public void doPost(HttpServletRequest req,HttpServletResponse res){this.doGet(req, res);}
}

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