时间：2023-05-31 03:57:01 | 来源：网站运营
时间：2023-05-31 03:57:01 来源：网站运营
Web开发模式【Mode I 和Mode II的介绍、应用案例】：
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public class Calculator { private double firstNum; private double secondNum; private char Operator = '+'; private double result; //JavaBean提供了计算的功能 public void calculate() { switch (this.Operator) { case '+': this.result = this.firstNum + this.secondNum; break; case '-': this.result = this.firstNum - this.secondNum; break; case '*': this.result = this.firstNum * this.secondNum; break; case '/': if (this.secondNum == 0) { throw new RuntimeException("除数不能为0"); } this.result = this.firstNum / this.secondNum; break; default: throw new RuntimeException("传入的字符非法！"); } } public double getFirstNum() { return firstNum; } public void setFirstNum(double firstNum) { this.firstNum = firstNum; } public double getSecondNum() { return secondNum; } public void setSecondNum(double secondNum) { this.secondNum = secondNum; } public char getOperator() { return Operator; } public void setOperator(char operator) { Operator = operator; } public double getResult() { return result; } public void setResult(double result) { this.result = result; } } <%--开发用户界面--%> <form action="/zhongfucheng/1.jsp" method="post"> <table border="1"> <tr> <td colspan="2">简单计数器</td> <td></td> </tr> <tr> <td>第一个参数：</td> <td><input type="text" name="firstNum"></td> </tr> <tr> <td>运算符</td> <td> <select name="operator"> <option value="+">+</option> <option value="-">-</option> <option value="*">*</option> <option value="/">/</option> </select> </td> </tr> <tr> <td>第二个参数：</td> <td><input type="text " name="secondNum"></td> </tr> <tr> <td colspan="2"><input type="submit" value="提交"></td> <td></td> </tr> </table> </form> <%--获取得到Bean对象--%> <jsp:useBean id="calculator" class="domain.Calculator" scope="page"/> <%--设置Bean对象的数据--%> <jsp:setProperty name="calculator" property="*"/> <%--调用Caculator的方法计算出值--%> <jsp:scriptlet> calculator.calculate(); </jsp:scriptlet> <%--得出的结果：--%> <c:out value="计算得出的结果是："/> <jsp:getProperty name="calculator" property="firstNum"/> <jsp:getProperty name="calculator" property="operator"/> <jsp:getProperty name="calculator" property="secondNum"/> <c:out value="="/> <jsp:getProperty name="calculator" property="result"/> private int id; private String username; private String password; private String email; private Date birthday; //....各种setter、getter//外界传递用户名和密码进来，我要在XML文档中查找是否有该条记录 public User find(String username, String password) { //得到XML文档的流对象 InputStream inputStream = UserImplXML.class.getClassLoader().getResourceAsStream("user.xml"); //得到dom4j的解析器对象 SAXReader saxReader = new SAXReader(); try { //解析XML文档 Document document = saxReader.read(path); //使用XPATH技术，查找XML文档中是否有传递进来的username和password Element element = (Element) document.selectSingleNode("//user[@username='" + username + "' and@password='" + password + "']"); if (element == null) { return null; } //如果有，就把XML查出来的节点信息封装到User对象，返回出去 User user = new User(); user.setId(Integer.parseInt(element.attributeValue("id"))); user.setUsername(element.attributeValue("username")); user.setPassword(element.attributeValue("password")); user.setEmail(element.attributeValue("email")); //生日就需要转换一下了，XML文档保存的是字符串，User对象需要的是Date类型 SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yy-MM-dd"); Date birthday = simpleDateFormat.parse(element.attributeValue("birthday")); user.setBirthday(birthday); //返回User对象出去 return user; } catch (DocumentException e) { e.printStackTrace(); throw new RuntimeException("初始化时候出错啦！"); } catch (ParseException e) { e.printStackTrace(); throw new RuntimeException("查询的时候出错啦！"); } } private String username = "zhongfucheng"; private String password = "123"; @Test public void testLogin() { UserImplXML userImplXML = new UserImplXML(); User user = userImplXML.find(username, password); System.out.println(user.getBirthday()); System.out.println(user.getEmail()); System.out.println(user.getId()); System.out.println(user.getUsername()); System.out.println(user.getPassword()); } //注册功能，外界传递一个User对象进来。我就在XML文档中添加一条信息 public void register(User user) { //获取XML文档路径！ String path = UserImplXML.class.getClassLoader().getResource("user.xml").getPath(); try { //获取dom4j的解析器，解析XML文档 SAXReader saxReader = new SAXReader(); Document document = saxReader.read(path); //在XML文档中创建新的节点 Element newElement = DocumentHelper.createElement("user"); newElement.addAttribute("id", String.valueOf(user.getId())); newElement.addAttribute("username", user.getUsername()); newElement.addAttribute("email", user.getEmail()); newElement.addAttribute("password", user.getPassword()); //日期返回的是指定格式的日期 SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yy-MM-dd"); String date = simpleDateFormat.format(user.getBirthday()); newElement.addAttribute("birthday",date); //把新创建的节点增加到父节点上 document.getRootElement().add(newElement); //把XML内容中文档的内容写到硬盘文件上 OutputFormat outputFormat = OutputFormat.createPrettyPrint(); outputFormat.setEncoding("UTF-8"); XMLWriter xmlWriter = new XMLWriter(new FileWriter(path),outputFormat); xmlWriter.write(document); xmlWriter.close(); } catch (DocumentException e) { e.printStackTrace(); throw new RuntimeException("注册的时候出错了！！！"); } catch (IOException e) { e.printStackTrace(); throw new RuntimeException("注册的时候出错了！！！"); } } @Test public void testRegister() { UserImplXML userImplXML = new UserImplXML(); //这里我为了测试的方便，就添加一个带5个参数的构造函数了！ User user = new User(10, "nihao", "123", "sina@qq.com", new Date()); userImplXML.register(user); } public class UserServiceXML { //Service层就是调用Dao层的方法，我们就直接在类中创建Dao层的对象了 UserDao userImplXML = new UserImplXML(); public void register(User user) { userImplXML.register(user); } public void login(String username, String password) { userImplXML.find(username, password); } }public class RegisterUIServlet extends javax.servlet.http.HttpServlet { protected void doPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException { //直接跳转到显示注册界面的JSP request.getRequestDispatcher("/WEB-INF/register.jsp").forward(request, response); } protected void doGet(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException { this.doPost(request, response); } }<h1>欢迎来到注册界面！</h1><%--提交给处理注册的处理Servlet--%><form method="post" action="${pageContext.request.contextPath}/RegisterServlet"> <table> <%--对于id来讲，是服务器分配的！不需要用户自己输入--%> <tr> <td>用户名</td> <td> <input type="text " name="username"> </td> </tr> <tr> <td>密码</td> <td> <input type="text" name="password"> </td> </tr> <tr> <td>确认密码</td> <td> <input type="text" name="password"> </td> </tr> <tr> <td>邮箱</td> <td> <input type="text" name="email"> </td> </tr> <tr> <td>生日</td> <td> <input type="text " name="birethday"> </td> </tr> <tr> <td> <input type="submit" value="提交"> </td> <td> <input type="reset" value="重置！"> </td> </tr> </table></form>//首先要接受Parameter的参数，封装到User里面去 String username = request.getParameter("username"); String password = request.getParameter("password"); //......如果参数过多，我们就要写好多好多类似的代码了.../* * 将Parameter参数的数据封装到Bean中，为了外边不用强转，这里就使用泛型了！ * * @request 由于要获取的是Parameter参数的信息，所以需要有request对象 * @tClass 本身是不知道封装什么对象的，所以用class * * */ public static <T> T request2Bean(HttpServletRequest httpServletRequest, Class<T> tClass) { try { //创建tClass的对象 T bean = tClass.newInstance(); //获取得到Parameter中全部的参数的名字 Enumeration enumeration = httpServletRequest.getParameterNames(); //遍历上边获取得到的集合 while (enumeration.hasMoreElements()) { //获取得到每一个带过来参数的名字 String name = (String) enumeration.nextElement(); //获取得到值 String value = httpServletRequest.getParameter(name); //把数据封装到Bean对象中 BeanUtils.setProperty(bean, name, value); } return bean; } catch (Exception e) { e.printStackTrace(); throw new RuntimeException("封装数据到Bean对象中出错了！"); } }//日期转换器 ConvertUtils.register(new DateLocaleConverter(), Date.class); /*生成ID*/ public static int makeId() { return Integer.parseInt(UUID.randomUUID().toString()); }User user = WebUtils.request2Bean(request, User.class); user.setId(WebUtils.makeId()); //调用service层的注册方法，实现注册 ServiceBussiness serviceBussiness = new UserServiceXML(); serviceBussiness.register(user);public class FormBean { //表单提交过来的数据全都是String类型的，birthday也不例外！ private String username; private String password; private String password2; private String email; private String birthday; /*用于判断表单提交过来的数据是否合法*/ public boolean validate() { return false; } //......各种setter、getter方法}public boolean validate() { //用户名不能为空，并且要是3-8的字符 abcdABcd if (this.username == null || this.username.trim().equals("")) { return false; } else { if (!this.username.matches("[a-zA-Z]{3,8}")) { return false; } } //密码不能为空，并且要是3-8的数字 if (this.password == null || this.password.trim().equals("")) { return false; } else { if (!this.password.matches("//d{3,8}")) { return false; } } //两次密码要一致 if (this.password2 != null && !this.password2.trim().equals("")) { if (!this.password2.equals(this.password)) { return false; } } //邮箱可以为空，如果为空就必须合法 if (this.email != null && !this.email.trim().equals("")) { if (!this.email.matches("//w+@//w+(//.//w+)+")) { System.out.println("邮箱错误了！"); return false; } } //日期可以为空，如果为空就必须合法 if (this.birthday != null && !this.birthday.trim().equals("")) { try { DateLocaleConverter dateLocaleConverter = new DateLocaleConverter(); dateLocaleConverter.convert(this.birthday); } catch (Exception e) { System.out.println("日期错误了！"); return false; } } //如果上面都没有执行，那么就是合法的了，返回true return true; } //将表单的数据封装到formBean中 FormBean formBean = WebUtils.request2Bean(request, FormBean.class); //验证表单的数据是否合法，如果不合法就跳转回去注册的页面 if(formBean.validate()==false){ request.getRequestDispatcher("/WEB-INF/register.jsp").forward(request, response); return; } try { //将表单的数据封装到User对象中 User user = WebUtils.request2Bean(request, User.class); user.setId(WebUtils.makeId()); //调用service层的注册方法，实现注册 ServiceBussiness serviceBussiness = new UserServiceXML(); serviceBussiness.register(user); } catch (Exception e) { e.printStackTrace(); }if (user.getEmail() == null) { newElement.addAttribute("email", ""); } else { newElement.addAttribute("email", user.getEmail()); } //如果不是空才格式化信息 if (user.getBirthday() != null) { //日期返回的是指定格式的日期 SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd"); String date = simpleDateFormat.format(user.getBirthday()); newElement.addAttribute("birthday", date); } else { newElement.addAttribute("birthday", ""); }解决办法：public static <T> T request2Bean(HttpServletRequest httpServletRequest, Class<T> tClass) { try { //创建tClass的对象 T bean = tClass.newInstance(); //获取得到Parameter中全部的参数的名字 Enumeration enumeration = httpServletRequest.getParameterNames(); //日期转换器 ConvertUtils.register(new DateLocaleConverter(), Date.class); //遍历上边获取得到的集合 while (enumeration.hasMoreElements()) { //获取得到每一个带过来参数的名字 String name = (String) enumeration.nextElement(); //获取得到值 String value = httpServletRequest.getParameter(name); //如果Parameter中的数据为""，那么我就不封装到User对象里边去！执行下一次循环 if (value == "") { continue; } else { //把数据封装到Bean对象中 BeanUtils.setProperty(bean, name, value); } } return bean; } catch (Exception e) { e.printStackTrace(); throw new RuntimeException("封装数据到Bean对象中出错了！"); } }//将表单的数据封装到formBean中 FormBean formBean = WebUtils.request2Bean(request, FormBean.class); //验证表单的数据是否合法，如果不合法就跳转回去注册的页面 if(formBean.validate()==false){ request.getRequestDispatcher("/WEB-INF/register.jsp").forward(request, response); return; } try { //这是第一种-------------------------- /*User user = new User(); user.setId(WebUtils.makeId()); BeanUtils.copyProperties(user,formBean);*/ //------------------------------------------ //这是第二种 User user1 = WebUtils.request2Bean(request,User.class); user1.setId(WebUtils.makeId()); //----------------------------------- //调用service层的注册方法，实现注册 ServiceBussiness serviceBussiness = new UserServiceXML(); serviceBussiness.register(user1); } catch (Exception e) { e.printStackTrace(); }现在还有问题，如果我填写信息不合法，提交给服务器验证以后，服务器应该告诉用户哪个信息不合法，而不是直接把跳转回注册界面，把所有的信息全部清空，让用户重新填写！//表单提交过来的数据全都是String类型的，birthday也不例外！ private String username; private String password; private String password2; private String email; private String birthday; //记录错误的信息 private HashMap<String, String> error = new HashMap<>(); /*用于判断表单提交过来的数据是否合法*/ public boolean validate() { //用户名不能为空，并且要是3-8的字符 abcdABcd if (this.username == null || this.username.trim().equals("")) { error.put("username", "用户名不能为空，并且要是3-8的字符"); return false; } else { if (!this.username.matches("[a-zA-Z]{3,8}")) { error.put("username", "用户名不能为空，并且要是3-8的字符"); return false; } } //密码不能为空，并且要是3-8的数字 if (this.password == null || this.password.trim().equals("")) { error.put("password", "密码不能为空，并且要是3-8的数字"); return false; } else { if (!this.password.matches("//d{3,8}")) { error.put("password", "密码不能为空，并且要是3-8的数字"); return false; } } //两次密码要一致 if (this.password2 != null && !this.password2.trim().equals("")) { if (!this.password2.equals(this.password)) { error.put("password2", "两次密码要一致"); return false; } } //邮箱可以为空，如果为空就必须合法 if (this.email != null && !this.email.trim().equals("")) { if (!this.email.matches("//w+@//w+(//.//w+)+")) { error.put("email", "邮箱不合法！"); return false; } } //日期可以为空，如果为空就必须合法 if (this.birthday != null && !this.birthday.trim().equals("")) { try { DateLocaleConverter dateLocaleConverter = new DateLocaleConverter(); dateLocaleConverter.convert(this.birthday); } catch (Exception e) { error.put("birthday", "日期不合法！"); return false; } } //如果上面都没有执行，那么就是合法的了，返回true return true; } //.....各种的setter和getter//验证表单的数据是否合法，如果不合法就跳转回去注册的页面 if(formBean.validate()==false){ //在跳转之前，把formbean对象传递给注册页面 request.setAttribute("formbean", formBean); request.getRequestDispatcher("/WEB-INF/register.jsp").forward(request, response); return; } //直接跳转到登陆界面 request.getRequestDispatcher("/WEB-INF/login.jsp").forward(request, response);<h1>这是登陆界面</h1><form action="${pageContext.request.contextPath}/LoginServlet" method="post"> <table> <tr> <td>用户名</td> <td><input type="text" name="username"></td> </tr> <tr> <td>密码</td> <td><input type="password" name="password"></td> </tr> <tr> <td><input type="submit" value="提交"></td> <td><input type="reset" name="重置"></td> </tr> </table></form>//获取提交过来的数据 String username = request.getParameter("username"); String password = request.getParameter("password"); //调用service层的方法，去查询数据库（XML）是否有该条记录 try { ServiceBussiness serviceBussiness = new UserServiceXML(); User user = serviceBussiness.login(username, password); if (user == null) { request.setAttribute("message", "用户名或密码是错的"); } else { request.setAttribute("message","登陆成功"); } } catch (Exception e) { e.printStackTrace(); request.setAttribute("message","登陆失败咯"); } request.getRequestDispatcher("/message.jsp").forward(request, response); <h1>这是首页！</h1> <a href="${pageContext.request.contextPath}/LoginUIServlet">登陆</a> <a href="${pageContext.request.contextPath}/RegisterUIServlet">注册</a> </body>如果文章有错的地方欢迎指正，大家互相交流。习惯在微信看技术文章的同学，可以关注微信公众号:Java3y
关键词：模式
