注册与登陆
注册：
首先 需要新建web项目，对数据库操作的服务(与需求有关)，模型(与数据库表有关)，工具包(DBOperator)．
ｓｅｒｖｌｅｔ 的类用来从前台活取数据，选择要做的事情，然后判断重定向到何处．
主要是doPost方法，和doGet方法
设置编码
request.setCharacterEncoding("UTF-8");
request.setCharacterEncoding("UTF-8");
从前台活取数据
String name = request.getParameter("name");
String pwd = request.getParameter("password");
也即从传过来的参数获取数据
将数据写入数据库
user usr = new user();
usr.setName(name);
usr.setPassword(pwd); //建立数据库模型对象即学生对象
StuManager stuM = new StuManagerimplement();//管理数据库
boolean flag=false; //标志，是否成功写入
flag = stuM.add(usr); //注意异常的处理,此处可能抛出异常．
跳转页面（重定向）
response.sendRedirect("index.jsp");
登陆：流程基本类似：
从前台活取数据，
传入数据库管理方法，并且在管理方法内返回是否登陆成功的标志．
根据返回的标志，通过ｓｅｒｖｌｅｔ 判断重定向到制定页面．
代码如下：
DBOperator.java 略
stuManagerImplement.java
1 package cn.hpu.service;
2
3 import java.sql.Connection;
4 import java.sql.PreparedStatement;
5 import java.sql.ResultSet;
6 import java.sql.SQLException;
7 import java.sql.Statement;
8
9 import cn.hpu.model.user;
10 import cn.hpu.util.DBOperator;
11
12 public class StuManagerimplement implements StuManager {
13
14 @Override
15 public boolean add(user usr) {
16 // TODO Auto-generated method stub
17 boolean flag=false;
18 Connection con =null;
19 PreparedStatement pst=null;
20 String sql=null;
21
22
23 try {
24 con=DBOperator.getConnection();
25 // System.out.println("YES");
26 // if(con!=null) System.out.println("OKOKO");
27 sql = "insert into user (name,password) values(?,?)";
28 pst = con.prepareStatement(sql);
29 pst.setString(1, usr.getName());
30 pst.setString(2, usr.getPassword());
31
32 int rows = pst.executeUpdate();
33 if(rows>0) flag =true;
34
35 } catch (SQLException e) {
36 // TODO Auto-generated catch block
37 System.out.println("insert exception !");
38 e.printStackTrace();
39 }finally{
40 DBOperator.close(pst, con);
41 }
42 return flag;
43 }
44
45 @Override
46 public boolean check(String name, String psw) {
47 // TODO Auto-generated method stub
48 //sql语句指针变量的声明
49 boolean flag =false ;
50 Statement st=null;
51 ResultSet rt = null;
52 user usr=new user();
53 String sql=null;
54 Connection con = null;
55
56 try {
57 con = DBOperator.getConnection(); //查询
58 sql ="select * from user where name="+name;
59 st= con.createStatement();
60 rt = st.executeQuery(sql);
61 // System.out.println(rt.getString("name"));
62 if(rt.next())
63 {
64 usr.setName(rt.getString("name"));
65 usr.setPassword(rt.getString("password"));
66
67 }
68 System.out.println(usr.getName()+usr.getPassword());
69 String str = usr.getPassword();
70 if(psw.equals(str)) flag =true; //验证
71
72 } catch (Exception e) {
73 // TODO: handle exception
74 System.out.println("check exception !");
75 }finally {
76 DBOperator.close(rt, st, con); //关闭
77 }
78 return flag;
79 }
80
81 }
ｓｅｒｖｌｅｔ 程序
register.java
1 package cn.hpu.servlet;
2
3 import java.io.IOException;
4 import javax.servlet.ServletException;
5 import javax.servlet.annotation.WebServlet;
6 import javax.servlet.http.HttpServlet;
7 import javax.servlet.http.HttpServletRequest;
8 import javax.servlet.http.HttpServletResponse;
9
10 import org.apache.catalina.connector.Response;
11
12 import cn.hpu.model.user;
13 import cn.hpu.service.StuManager;
14 import cn.hpu.service.StuManagerimplement;
15
16 /**
17 * Servlet implementation class register
18 */
19 @WebServlet("/register")
20 public class register extends HttpServlet {
21 private static final long serialVersionUID = 1L;
22
23 /**
24 * @see HttpServlet#HttpServlet()
25 */
26 public register() {
27 super();
28 // TODO Auto-generated constructor stub
29 }
30
31 /**
32 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
33 */
34 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
35 // TODO Auto-generated method stub
36 response.getWriter().append("Served at: ").append(request.getContextPath());
37 doPost(request, response);
38 }
39
40 /**
41 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
42 */
43 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
44 // TODO Auto-generated method stub
45 // doGet(request, response);
46 //设置中文
47 request.setCharacterEncoding("UTF-8");
48 response.setCharacterEncoding("UTF-8");
49
50 //获取数据
51 String name = request.getParameter("name");
52 String pwd = request.getParameter("password");
53 // String code = request.getParameter("code");
54
55 user usr = new user();
56 usr.setName(name);
57 // usr.setCode(code);
58 usr.setPassword(pwd);
59
60 StuManager stuM = new StuManagerimplement();
61 boolean flag= false ;
62 try {
63 flag = stuM.add(usr);
64 if(flag) response.sendRedirect("index.jsp");
65
66 } catch (Exception e) {
67 // TODO: handle exception
68 }
69 }
70
71 }
login.java
1 package cn.hpu.servlet;
2
3 import java.io.IOException;
4 import java.io.PrintWriter;
5
6 import javax.servlet.ServletException;
7 import javax.servlet.annotation.WebServlet;
8 import javax.servlet.http.HttpServlet;
9 import javax.servlet.http.HttpServletRequest;
10 import javax.servlet.http.HttpServletResponse;
11
12 import cn.hpu.service.StuManager;
13 import cn.hpu.service.StuManagerimplement;
14
15 /**
16 * Servlet implementation class login
17 */
18 @WebServlet("/login")
19 public class login extends HttpServlet {
20 private static final long serialVersionUID = 1L;
21
22 /**
23 * @see HttpServlet#HttpServlet()
24 */
25 public login() {
26 super();
27 // TODO Auto-generated constructor stub
28 }
29
30 /**
31 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
32 */
33 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
34 // TODO Auto-generated method stub
35 response.getWriter().append("Served at: ").append(request.getContextPath());
36 doPost(request, response);
37 }
38
39 /**
40 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
41 */
42 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
43 // TODO Auto-generated method stub
44 // doGet(request, response);
45 request.setCharacterEncoding("UTF-8");
46 request.setCharacterEncoding("UTF-8");
47
48 String name = request.getParameter("name");
49 String pwd = request.getParameter("password");
50
51 StuManager stuM = new StuManagerimplement();
52 boolean flag= false ;
53
54 try {
55 flag = stuM.check(name,pwd);
56 if(flag) response.sendRedirect("loginsuccess.jsp");
57 } catch (Exception e) {
58 // TODO: handle exception
59 response.setContentType("text/html");
60 PrintWriter out = response.getWriter();
61 out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
62 out.println("<HTML>");
63 out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
64 out.println(" <BODY>");
65 out.println("<h1>");
66 out.println("用户名或密码错误登录失败！！");
67 out.println("<h1>");
68 out.println(" </BODY>");
69 out.println("</HTML>");
70 out.flush();
71 out.close();
72 }
73 }
74
75 }
index.jsp
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 4 <html> 5 <head> 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 7 <title>Insert title here</title> 8 </head> 9 <body> 10 <form action="login" method="post" align="center"> 11 <cneter><h1>用户信息管理系统</h1></cneter> 12 <b>用户名：</b><input type="text" name="name"><br> 13 <p></p> 14 <b>密 码：</b><input type="password" name="password"><br> 15 16 <font size="+1" > 17 <p> 18 <input name="submit" type="submit" class="button" style="width:200px; height:35px " value="登录" /> 19 </p> 20 <p><font size="-1" color="#000099"> 忘记密码？</font> <font size="-1" color="#000099"><a href="register.jsp">新用户</a> </font> </p> 21 </font> 22 23 </form> 24 25 </body> 26 </html>
register.jsp
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 4 <html> 5 <head> 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 7 <title>Insert title here</title> 8 </head> 9 <body> 10 <h1 align="center">注册新用户</h1> 11 <hr/> 12 <form action="register" method="post" align="center" > 13 用户名:<input name="name" type="text"/><br/> 14 <p></p> 15 密 码:<input name="password" type="password"/><br/> 16 <p></p> 17 验证码:<input name="code" type="text"><br/> 18 <p></p> 19 <input type="submit" style="width:80px; height:35px "value="注册" /> 20 </form> 21 <a href="index.jsp">返回 </a> 22 </body> 23 </html>
loginsuccess.jsp
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 4 <html> 5 <head> 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 7 <title>Insert title here</title> 8 </head> 9 <body> 10 <h1>恭喜登录成功！！</h1> 11 </body> 12 </html>
时间： 2024-08-09 19:51:46