超全面的JavaWeb笔记day14<用户注册登录>
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案例:用户注册登录
要求:3层框架,使用验证码
1 功能分析
l 注册
l 登录
1.1 JSP页面
l regist.jsp
Ø 注册表单:用户输入注册信息;
Ø 回显错误信息:当注册失败时,显示错误信息;
l login.jsp
Ø 登录表单:用户输入登录信息;
Ø 回显错误便利店:当登录失败时,显示错误信息;
l index.jsp
Ø 用户已登录:显示当前用户名,以及“退出”链接;
Ø 用户未登录:显示“您还没有登录”;
1.2 实体类
User:
l String username;
l String password;
1.3 Servlet
l VerifyCodeServlet
Ø 生成验证码;
Ø 在session中保存验证码文本;
Ø 把图片输出到页面
l RegistServlet
Ø 获取用户名、密码,封装到User对象中;
Ø 获取验证码、获取确认密码;
Ø 校验用户名、密码、验证码不能为空,校验失败,向request中保存错误信息,转发回regist.jsp显示错误信息;
Ø 比较两次输入的错误是否一致,如果不一致,向request中保存错误信息,转发回regist.jsp显示错误信息;
Ø 获取session中的验证码,与表单输入的验证码比较,如果不一致,向request中保存错误信息,转发回regist.jsp显示错误信息;
Ø 使用UserService的regist()方法完成注册,如果注册失败,向request中保存错误信息,转发回regist.jsp显示错误信息,如果注册成功,转发到login.jsp页面,表示注册成功;
l LoginServlet
Ø 获取用户名、密码、验证码;
Ø 校验用户名、密码、验证码是否为空,校验失败,向request中保存错误信息,转发回login.jsp显示错误信息;
Ø 获取session中的验证码,与表单中的验证码比较,如果不同,向request中保存错误信息,转发回login.jsp显示错误信息;
Ø 删除session中的验证码;
Ø 通过UserService的login()方法完成登录,如果抛出异常,获取异常信息,保存到request中,转发到login.jsp显示错误信息;
Ø 向session中保存当前用户对象;
Ø 转发到index.jsp页面,表示登录成功!
l QuitServlet
Ø 获取session,销毁之;
Ø 重定向到index.jsp;
1.4 Service
UserException:为UserService使用的异常类;
UserService:
l void regist(User user):
Ø 使用UserDao的findByUsername()方法查询名为user.getUsername()的用户,如果用户存在,说明用户名已经被注册,抛出异常;
Ø 使用UserDao的add(User)方法保存用户信息;
l User login(String username, String password):
Ø 使用UserDao的findByUsername()方法查询名为user.getUsername()的用户,如果用户不存在,说明用户名错误,抛出异常;
Ø 如果查询到了User,那么比较参数password与user.getPassword()是否相等,如果不等,说明密码错误,抛出异常;
Ø 如果一致,表示登录成功,返回User对象;
1.5 DAO
UserDao:
l void add(User):
Ø 创建SAXReader对象,获取Document对象,再获取根元素;
Ø 给root元素添加子元素;
Ø 给子元素设置username属性,值为user.getUsername();
Ø 给子元素设置password属性,值为user.getPassword();
Ø 创建OutputFormat对象,指定缩进为“\t”,指定添加换行;
Ø 设置OutputFormat清空原有空白;
Ø 使用FileWrtier和OutputFormat创建XMLWriter对象;
Ø 使用XMLWriter对象的write()保存Document;
Ø 关闭XMLWriter对象;
l User findByUsername(String username):
Ø 创建SAXReader对象,获取Document对象;
Ø 使用Xpath(//user[username=’xxx’])来查询元素;
Ø 如果元素没有查询到,返回null;
Ø 如果元素查询到了,那么创建User对象;
Ø 把元素的username属性赋给User的username属性;
Ø 把元素的password属性赋给User的password属性;
Ø 返回user对象;
2 2 流程图
2.1 注册
l 用户在浏览器地址栏中请求regist.jsp;
l 服务器发送html给浏览器;
l 浏览器收到html,开始解析,并显示;
l 解析到<img>时,请求VerifyCodeServlet;
l VerifyCodeServlet生成验证码图片,保存验证码文本,把图片响应给浏览器;
l 浏览器显示在页面中显示图片。
2.2 登录
此处省略10000字
3 3 代码
login.jsp
<body>
<h1>登录</h1>
<hr/>
<p style="font-weight: 900; color: red;">${msg }</p>
<form action="<c:url value='/LoginServlet'/>" method="post">
用户名:<input type="text" name="username" value="${user.username }" /><br/>
密 码:<input type="password" name="password"/><br/>
验证码:<input type="text" name="loginCode" size="2"/>
<img id="vCode" src="<c:url value='/VerifyCodeServlet?name=loginCode'/>" border="2"/>
<a href="javascript:_change()" style="font-size: 12;">看不清,换一张</a><br/>
<input type="submit" value="登录"/>
</form>
</body>
<script type="text/javascript">
function _change() {
var img = document.getElementById("vCode");
img.src = "<c:url value='/VerifyCodeServlet?name=loginCode&'/>" + new Date().getTime();
}
</script>
regist.jsp
<body>
<h1>注册</h1>
<hr/>
<p style="font-weight: 900; color: red;">${msg }</p>
<form action="<c:url value='/RegistServlet'/>" method="post">
用户名:<input type="text" name="username" value="${user.username }" /><br/>
密 码:<input type="password" name="password"/><br/>
确认密码:<input type="password" name="repassword"/><br/>
验证码:<input type="text" name="registCode" size="2"/>
<img id="vCode" src="<c:url value='/VerifyCodeServlet?name=registCode'/>" border="2"/>
<a href="javascript:_change()" style="font-size: 12;">看不清,换一张</a><br/>
<input type="submit" value="注册"/>
</form>
</body>
<script type="text/javascript">
function _change() {
var img = document.getElementById("vCode");
img.src = "<c:url value='/VerifyCodeServlet?name=registCode&'/>" + new Date().getTime();
}
</script>
index.jsp
<body>
<h1>主页</h1>
<hr/>
<c:choose>
<c:when test="${empty sessionScope.user }">
您还没有登录
</c:when>
<c:otherwise>
用户名:${sessionScope.user.username }
<a href="<c:url value='/QuitServlet'/>">退出</a>
</c:otherwise>
</c:choose>
</body>
VerifyCodeServlet
public class VerifyCodeServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
String name = request.getParameter("name");
VerifyCode vc = new VerifyCode();//创建验证码类
BufferedImage image = vc.getImage();//创建验证码图片
request.getSession().setAttribute(name, vc.getText());//获取验证码文本
System.out.println(vc.getText());
VerifyCode.output(image, response.getOutputStream());//输出图片到页面
}
}
RegistServlet
public class RegistServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
User user = new User();
try {
BeanUtils.populate(user, request.getParameterMap());
} catch (Exception e) {
}
String loginCode = request.getParameter("registCode");
String repassword = request.getParameter("repassword");
if(user.getUsername() == null || user.getUsername().trim().isEmpty()) {
request.setAttribute("msg", "用户名不能为空!");
request.setAttribute("user", user);
request.getRequestDispatcher("/regist.jsp").forward(request, response);
return;
}
if(user.getPassword() == null || user.getPassword().trim().isEmpty()) {
request.setAttribute("msg", "密码不能为空!");
request.setAttribute("user", user);
request.getRequestDispatcher("/regist.jsp").forward(request, response);
return;
}
if(!user.getPassword().equals(repassword)) {
request.setAttribute("msg", "两次输入不一致!");
request.setAttribute("user", user);
request.getRequestDispatcher("/regist.jsp").forward(request, response);
return;
}
if(loginCode == null || loginCode.trim().isEmpty()) {
request.setAttribute("msg", "验证码不能为空!");
request.setAttribute("user", user);
request.getRequestDispatcher("/regist.jsp").forward(request, response);
return;
}
String vCode = (String)request.getSession().getAttribute("registCode");
request.getSession().removeAttribute("registCode");
if(!vCode.equalsIgnoreCase(loginCode)) {
request.setAttribute("msg", "验证码错误!");
request.setAttribute("user", user);
request.getRequestDispatcher("/regist.jsp").forward(request, response);
return;
}
UserService userService = new UserService();
try {
userService.regist(user);
request.getRequestDispatcher("/login.jsp").forward(request, response);
} catch (UserException e) {
request.setAttribute("msg", e.getMessage());
request.setAttribute("user", user);
request.getRequestDispatcher("/regist.jsp").forward(request, response);
return;
}
}
}
LoginServlet
public class LoginServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
String username = request.getParameter("username");
String password = request.getParameter("password");
String loginCode = request.getParameter("loginCode");
if(username == null || username.trim().isEmpty()) {
request.setAttribute("msg", "用户名不能为空!");
request.setAttribute("username", username);
request.getRequestDispatcher("/login.jsp").forward(request, response);
return;
}
if(password == null || password.trim().isEmpty()) {
request.setAttribute("msg", "密码不能为空!");
request.setAttribute("username", username);
request.getRequestDispatcher("/login.jsp").forward(request, response);
return;
}
if(loginCode == null || loginCode.trim().isEmpty()) {
request.setAttribute("msg", "验证码不能为空!");
request.setAttribute("username", username);
request.getRequestDispatcher("/login.jsp").forward(request, response);
return;
}
String vCode = (String)request.getSession().getAttribute("loginCode");
request.getSession().removeAttribute("loginCode");
if(!vCode.equalsIgnoreCase(loginCode)) {
request.setAttribute("msg", "验证码错误!");
request.setAttribute("username", username);
request.getRequestDispatcher("/login.jsp").forward(request, response);
return;
}
UserService userService = new UserService();
User user;
try {
user = userService.login(username, password);
} catch (UserException e) {
request.setAttribute("msg", e.getMessage());
request.setAttribute("username", username);
request.getRequestDispatcher("/login.jsp").forward(request, response);
return;
}
request.getSession().setAttribute("user", user);
request.getRequestDispatcher("/index.jsp").forward(request, response);
}
}
QuitServlet
public class QuitServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
// 使session失效
request.getSession().invalidate();
response.sendRedirect(request.getContextPath() + "/index.jsp");
}
}
UserException
public class UserException extends Exception {
public UserException() {}
public UserException(String message, Throwable cause) {
super(message, cause);
}
public UserException(String message) {
super(message);
}
public UserException(Throwable cause) {
super(cause);
}
}
UserService
public class UserService {
private UserDao userDao = new UserDao();
public User login(String username, String password) throws UserException {
User user = userDao.findByUsername(username);
if(user == null) {
throw new UserException("用户名错误!");
}
if(!user.getPassword().equals(password)) {
throw new UserException("密码错误!");
}
return user;
}
public void regist(User user) throws UserException {
User _user = userDao.findByUsername(user.getUsername());
if(_user != null) {
throw new UserException("用户名已注册!");
}
userDao.add(user);
}
}
UserDao
public class UserDao {
private String path;
public UserDao() {
path = this.getClass().getResource("/users.xml").getPath();
}
public void add(User user) {
try {
SAXReader reader = new SAXReader();
Document doc = reader.read(path);
Element root = doc.getRootElement();
Element userEle = root.addElement("user");
userEle.addAttribute("username", user.getUsername());
userEle.addAttribute("password", user.getPassword());
// 创建格式化器,使用\t缩进,添加换行
OutputFormat format = new OutputFormat("\t", true);
// 清空数据中原有的换行
format.setTrimText(true);
// 创建XML输出流对象
XMLWriter writer = new XMLWriter(new FileWriter(path), format);
// 输出Document
writer.write(doc);
// 关闭流
writer.close();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public User findByUsername(String username) {
try {
SAXReader reader = new SAXReader();
Document doc = reader.read(path);
Element ele = (Element) doc.selectSingleNode("//user[@username='" + username + "']");
if(ele == null) {
return null;
}
User user = new User();
user.setUsername(ele.attributeValue("username"));
user.setPassword(ele.attributeValue("password"));
return user;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
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