千锋20200417

在千锋“逆战”学习第55天

      每日一句：测试是来表明bug的存在而不是不存在
      今天学习了response操作响应正文、request操作请求行、request操作请求头、request操作请求参数、请求参数中文乱码、request操作请求转发、请求转发和重定向、request作为域对象。
      下周继续努力。

---

作业

• User.java

public class User {
    private String username;
    private String password;

    public User() {
    }

    public User(String username, String password) {
        this.username = username;
        this.password = password;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "User{" +
                "username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

• InitServlet.java

@WebServlet(name = "InitServlet",urlPatterns = "/initServlet",loadOnStartup = 1)
public class InitServlet extends HttpServlet {
    @Override
    public void init() throws ServletException {
        //创建一个List集合保存用户注册信息
        List<User> userList = new ArrayList<User>();
        //将List集合保存到ServletContext作用域
        this.getServletContext().setAttribute("list",userList);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }
}

• RegisterServlet

@WebServlet(name = "RegisterServlet",urlPatterns = "/registerServlet")
public class RegisterServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        DiskFileItemFactory diskFileItemFactory = new DiskFileItemFactory();
        ServletFileUpload servletFileUpload = new ServletFileUpload(diskFileItemFactory);
        try {
            Map<String, String> map = new HashMap < String, String>();
            List<FileItem> list = servletFileUpload.parseRequest(request);
            for (FileItem fileItem : list) {
                String name = fileItem.getFieldName();
                String value = fileItem.getString("utf-8");
                map.put(name,value);
            }
            List<User> userList = (List<User>) this.getServletContext().getAttribute("list");
            //检验用户名
            for(User u:userList){
                if(u.getUsername().equals(map.get("username"))){
                    request.setAttribute("msg","用户名存在");
                    request.getRequestDispatcher("/register.html").forward(request,response);
                    return;
                }
            }
            User user = new User();
            user.setUsername(map.get("username"));
            user.setPassword(map.get("password"));
            userList.add(user);
            this.getServletContext().setAttribute("list",userList);
            request.getRequestDispatcher("/login.html").forward(request,response);
        } catch (FileUploadException e) {
            e.printStackTrace();
        }
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request,response);

    }
}

• LoginServlet

@WebServlet(name = "LoginServlet",urlPatterns = "/loginServlet")
public class LoginServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        //从ServletContext域中获得用户信息
        List<User> list = (List<User>) this.getServletContext().getAttribute("list");
        for(User user:list){
            if(username.equals(user.getUsername())&&password.equals(user.getPassword())){
                request.getSession().setAttribute("user",user);
                response.sendRedirect("success.html");
                return;
            }
        }
        request.setAttribute("msg","登录失败");
        request.getRequestDispatcher("/login.html").forward(request,response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }
}

• login.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>登录</title>
</head>
<body>
<form action="/loginServlet" method="post">
    用户名：<input type="text" name="username"><br>
    密码：<input type="password" name="password"><br>
    <button type="submit">登录</button>
</form>
</body>
</html>

• register.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>注册</title>
</head>
<body>
    <form action="/registerServlet" method="post">
        用户名：<input type="text" name="username"><br>
        密码：<input type="password" name="password"><br>
        <button type="submit">注册</button>
    </form>
</body>
</html>

• success.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>登录成功</title>
</head>
<body>
    登录成功
</body>
</html>