Day13--JavaWeb学习之Servlet后端渲染界面

基于Day12中登录页面实现的修改，这里实现的是如果登录成功，跳到LoginSuccess页面中展示后端查询到数据库中的信息，并实现在浏览器实现插入数据和删除数据（mybaits）。

当输入账号密码正确后进入LoginSuccess页面，通过resp.getWriter来编写后端需要渲染的页面。

数据删除：

后端渲染数据展示的页面

在数据展示页面增加删除操作按钮，让点击后跳转到@WebServlet("/DelUser")，真正实现数据删除的地方

@WebServlet("/LoginSuccess")
public class LoginSuccess extends HttpServlet {//收参数@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {this.doPost(req, resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {List<Student> info = (List<Student>) req.getAttribute("AllInfo");PrintWriter wr = resp.getWriter();wr.write("<!DOCTYPE html>");wr.println("<html>");wr.println("<head>");wr.write("</head>");wr.println("<body>");wr.write("<table cellpadding='2' cellspacing='2' center='100%' border='1'>");wr.write("<tr><th>学号</th><th>姓名</th><th>性别</th><th>年龄</th><th>专业</th><th>操作</th></tr>");wr.write("<tr><a href='Insert'>信息录入</a></tr>");for (int i = 0; i < info.size(); i++) {wr.write("<tr>");wr.write("<td>" + info.get(i).getSno() + "</td>");wr.write("<td>" + info.get(i).getName() + "</td>");wr.write("<td>" + info.get(i).getSex() + "</td>");wr.write("<td>" + info.get(i).getAge() + "</td>");wr.write("<td>" + info.get(i).getMajor() + "</td>");wr.write("<td> <a onclick=\"if(confirm('确认删除吗？'))return true;return false;\" " +"href=DelUser?Sno="+ info.get(i).getSno()+">删除</a></td>");wr.write("</tr>");}wr.write("</table>");wr.println("</body>");wr.println("</html>");}
}

实现执行删除的操作代码：

@WebServlet("/DelUser")
public class DelUser extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {this.doPost(req, resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {req.setCharacterEncoding("UTF-8");resp.setContentType("text/html;charset=utf-8");String Sno = req.getParameter("Sno");System.out.println("Sno = " + Sno);GetMapper getMapper = new GetMapper();getMapper.delete(Integer.valueOf(Sno));ArrayList<Student> stu = getMapper.selectAll();req.setAttribute("AllInfo", stu);if (!stu.isEmpty()) {req.getRequestDispatcher("LoginSuccess").forward(req, resp);}}
}

数据的插入：

后端渲染数据插入的页面

@WebServlet("/Insert")
public class Insert extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {this.doPost(req, resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {req.setCharacterEncoding("UTF-8");resp.setContentType("text/html;charset=utf-8");PrintWriter wr = resp.getWriter();wr.println("<html>");wr.println("<head>");wr.println("<title>Servlet Insert</title>");wr.println("</head>");wr.println("<body>");wr.println("<h1>Servlet Insert </h1>");wr.write("<div class='container'> " +"<form action='InsertOk'>"+"学号：<input type='text' name='sno'><br>" +"姓名：<input type='text' name='name'><br>" +"性别：<input type='text' name='sex'><br>" +"年龄：<input type='text' name='age'><br>" +"专业：<input type='text' name='major'><br>"+"<button>提交添加</button>" +"</form>"+"</div>");wr.println("</body>");wr.println("</html>");}
}

后端处理数据插入的代码：

@WebServlet("/InsertOk")
public class InsertOk extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {this.doPost(req, resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {req.setCharacterEncoding("UTF-8");resp.setContentType("text/html;charset=utf-8");String major = req.getParameter("major");String age = req.getParameter("age");String sex = req.getParameter("sex");String name = req.getParameter("name");String sno = req.getParameter("sno");Student student = new Student(Integer.valueOf(sno),name,sex,Integer.valueOf(age),major);GetMapper getMapper = new GetMapper();getMapper.insert(student);ArrayList<Student> stu = getMapper.selectAll();req.setAttribute("AllInfo", stu);if (!stu.isEmpty()) {req.getRequestDispatcher("LoginSuccess").forward(req, resp);}}
}