一、Servlet使用
1、新建servlet包
2、新建FirstServlet類（new-Servlet），父類爲HttpServlet
public void destroy() {
super.destroy();
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<HTML>");
out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
out.println(" <BODY>");
out.println("<h1>hello</h1>");
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
3、查看部署文件（Web.xml)
<servlet>
<servlet-name>FirstSevlet</servlet-name>
<servlet-class>servlet.FirstSevlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>FirstSevlet</servlet-name>
<url-pattern>/user/FirstSevlet</url-pattern>
</servlet-mapping>
4、地址欄訪問http://localhost:8080/test/user/FirstSevlet
頁面顯示hello
二、實現用戶登錄處理
1、登陸頁內容
<FORM METHOD=POST ACTION="user/UserServlet？type=login">
<table border="0" style="margin:10px 0 0 10px;">
<tbody><tr>
<td width="50%" valign="top">用戶名：</td>
<td><input type="text" name="name" class="txt" size="10"></td>
</tr>
<tr>
<td>密 碼：</td>
<td>
<INPUT TYPE="password" NAME="password" size="10" class="txt">
</td>
</tr>
<tr>
<td align="center"><INPUT class="txt" TYPE="submit" value="登錄"></td>
<td><INPUT class="txt"TYPE="button" onclick="location.href='register.jsp'" value="註冊"></td>
</tr>
</tbody>
</table>
</form>
2、新建UserServlet類（url:user/UserServlet）
doPost方法代碼：
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String type=request.getParameter("type");
if("login".equals(type)){
String name = request.getParameter("name");
String pwd = request.getParameter("password");
UserDAO dao=new UserDAO();
User u=dao.login(name, pwd);
if(u!=null){
//request.getRequestDispatcher("index.php").forward(request, response);
request.getSession().setAttribute("user",u); //session實現保存用戶信息
response.sendRedirect("../index.jsp");
}else{
response.sendRedirect("../index.jsp");
}
}
}
其中UserDAO中login（）方法代碼
public class UserDAO {
public User login(String name,String pwd)
{
User u=null; //添加
Connection conn=null;
PreparedStatement ps=null;
ResultSet rs=null;
String sql="select * from users where name=? and password=?";
try {
Class.forName(Const.DRIVER);
conn=DriverManager.getConnection(Const.URL, Const.USER, Const.PASSWORD);
ps=conn.prepareStatement(sql);
ps.setString(1, name);
ps.setString(2, pwd);
rs=ps.executeQuery();
if(rs.next()){
u=new User();
u.setUid(rs.getInt("uid"));
u.setName(rs.getString("name"));
u.setPassword(rs.getString("password"));
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if(rs!=null)
rs.close();
if(ps!=null)
ps.close();
if(conn!=null)
conn.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return u;
}
3、web.xml部署
<servlet>
<servlet-name>UserServlet</servlet-name>
<servlet-class>servlet.UserServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UserServlet</servlet-name>
<url-pattern>/user/UserServlet</url-pattern>
</servlet-mapping>
4、實現顯示登錄用戶名等信息
left部分判斷是否登錄過用戶，如果登錄顯示相關信息
<div class="person">
<img src="p_w_picpaths/personal.gif">
<%
User user=(User)session.getAttribute("user");
if(user==null)
{
%>
<FORM METHOD=POST ACTION="user/UserServlet?type=login">
<table border="0" style="margin:10px 0 0 10px;">
<tbody><tr>
<td width="50%" valign="top">用戶名：</td>
<td><input type="text" name="name" class="txt" size="10"></td>
</tr>
<tr>
<td>密 碼：</td>
<td>
<INPUT TYPE="password" NAME="password" size="10" class="txt">
</td>
</tr>
<tr>
<td align="center"><INPUT class="txt" TYPE="submit" value="登錄"></td>
<td><INPUT class="txt"TYPE="button" onclick="location.href='register.jsp'" value="註冊"></td>
</tr>
</tbody>
</table>
</form>
<%}else{%>
<ul>
<li>您好:</li>
<li><%=user.getName() %></li>
<li><a href="person.jsp">個人信息:</a></li>
<li><a href="user/UserServlet?type=exit">退出</a></li>
</ul>
<%} %>
</div>
三、Servlet實現用戶註銷
1、left頁
<a href="/user/UserServlet?type=exit">註銷</a>
2、UserServlet的doGet方法實現用戶註銷，返回首頁
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String type=request.getParameter("type");
if("exit".equals(type)){
request.getSession().invalidate();
response.sendRedirect("../index.jsp");
}
}
四、Servlet實現刪除用戶功能
1、user_view.jsp實現顯示用戶信息（admin/user_view.jsp）
<tr>
<td><%=u.getUid()%></td>
<td><%=u.getName()%></td>
<td><%=u.getEmail()%></td>
<td><a href="../user/UserSevlet?type=delete&uid=<%=u.getUid()%>">刪除</a></td>
<td><a href="#">修改</a></td>
<td>詳細</td>
</tr>
2、UserServlet的doGet方法實現刪除用戶
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
String type=request.getParameter("type");
if("exit".equals(type)){
request.getSession().invalidate();
response.sendRedirect("../index.jsp");
}else if("delete".equals(type)){
String uid=request.getParameter("uid");
UserDAO dao=new UserDAO();
dao.delete(Integer.parseInt(uid));
response.sendRedirect("../admin/index.jsp");
}
路徑關係
---admin/index.jsp（後臺主頁）①
---admin/user_view.jsp(後臺查看用戶信息頁）②
---user/UserServlet③
---index.jsp(前臺主頁）④
③-->④response.sendRedirect("../index.jsp");
③-->① response.sendRedirect("../admin/index.jsp");
④-->③ user/UserServlet
①或②-->③ ../user/UserServlet