问题描述
因为在之前的练习中每写一个功能都需要一个Servlet,那Servlet的数量就会相对较多,现在优化为一个模块一个Servlet,相当于数据库中一张表对应一个Servlet,在Servlet中提供不同的方法,完成用户的请求
实现
- 定义一个BaseServlet类,继承HttpServlet,复写service方法,这样请求进入到service方法中。
- 定义servlet,继承BaseServlet,设置访问路径为多一级目录形式(例如:"/user/*"),定义方法,编写功能实现
- 在BaseServlet的service方法中利用反射调用servlet的方法
还不懂,上图
代码实现
BaseServlet
public class BaseServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//获取请求的url路径
StringBuffer url = req.getRequestURL();
//获取方法名
String methodName = url.substring(url.lastIndexOf("/") + 1);
//这里判断请求的是否为html页面
if(methodName.endsWith(".html")){
//获取页面父路径
String url_html = url.substring(0,url.lastIndexOf("/",url.lastIndexOf("/")-1)+1);
//重定向到指定页面
resp.sendRedirect(url_html+methodName);
}
try {
//通过反射获取方法对象
Method method = this.getClass().getMethod(methodName, HttpServletRequest.class, HttpServletResponse.class);
//执行方法,this代表当前路径的Servlet类
method.invoke(this,req,resp);
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
}
Servlet
@WebServlet("/user/*")
public class UserServlet extends BaseServlet {
private UserService userService = new UserServiceImpl();
/**
* 用户注册
* @param req
* @param resp
* @throws ServletException
* @throws IOException
*/
public void register(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
HttpSession session = req.getSession();
String checkcode = (String)session.getAttribute("CHECKCODE_SERVER");
String check = req.getParameter("check");
ResultInfo info = new ResultInfo();
boolean flag = false;
if(check.equalsIgnoreCase(checkcode)){
session.removeAttribute("CHECKCODE_SERVER");
Map<String, String[]> map = req.getParameterMap();
User user = new User();
try {
BeanUtils.populate(user,map);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
flag = userService.register(user);
info.setFlag(flag);
if(!flag){
info.setErrorMsg("注册失败");
}
}else{
info.setFlag(flag);
info.setErrorMsg("验证码错误");
}
ObjectMapper jackson = new ObjectMapper();
String infostr = jackson.writeValueAsString(info);
resp.setContentType("application/json;charset=utf-8");
resp.getWriter().write(infostr);
//jackson.writeValue(resp.getWriter(),info);
}
/**
* 账号激活
* @param req
* @param resp
* @throws ServletException
* @throws IOException
*/
public void active(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//功能实现代码
}
/**
* 用户登录
* @param req
* @param resp
* @throws ServletException
* @throws IOException
*/
public void login(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//功能实现代码
}
完成!