java登录注册插件_使用Servlet实现登录和注册功能

1.分析：

1、注册功能

(1)前端

1.注册表单、用户名、密码、单选、复选、下拉列表控件编写

2.action属性跳转到后台；name属性传参数到后台

(2)后台

1.新建注册Servlet，用request接收参数；response返回数据到前端

(3)处理乱码

1.request的doGet请求：new String(username.getBytes("iso-8859-1"), "utf-8");

2.response的doGet/doPost请求：response.setContentType("text/html;charset=utf-8");

3.request的doPost请求：request.setCharacterEncoding("utf-8");

(4)doGet与doPost区别

1.doGet将参数从url中传到后台，不安全，性能高；只能传文本参数

2.doPost以请求体方式传到后台，安全，性能低；可以传文本及二进制

2、登录功能

(1)前端控件的编写，action属性跳到LoginServlet

(2)后台判断登录是否成功

2.实现代码

public class LoginServlet extends HttpServlet {

private static final long serialVersionUID = 1L;

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

//1.doGet/doPost的response的乱码:

response.setContentType("text/html;charset=utf-8");

//3.doPost的request的乱码

request.setCharacterEncoding("utf-8");

String username = request.getParameter("username");

String password = request.getParameter("password");

if("zs".equals(username)&&"123".equals(password)){

response.getWriter().write("登录成功");

}else{

response.getWriter().write("登录失败 ");

}

}

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

doGet(request, response);

}

}

public class RegisterServlet extends HttpServlet {

private static final long serialVersionUID = 1L;

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

//注意： 往往乱码处理尽可能放到最上面

//1.doGet/doPost的response的乱码:

response.setContentType("text/html;charset=utf-8");

//3.doPost的request的乱码

request.setCharacterEncoding("utf-8");

String username = request.getParameter("username");

//2.doGet的request的乱码

//username = new String(username.getBytes("iso-8859-1"),"utf-8");

String password = request.getParameter("password");

String sex = request.getParameter("sex");

String[] loves = request.getParameterValues("loves");

String province = request.getParameter("province");

System.out.println(username+"--"+password+"--"+sex);

System.out.println(Arrays.toString(loves)+"--"+province);

if("zs".equals(username)){

response.getWriter().write("已注册~！");

}else{

response.getWriter().write("3秒后自动跳转到登录页面！");

response.setHeader("refresh", "3;url='login.html'");

}

}

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

System.out.println("doPost....");

doGet(request, response);

}

}

3.前端

用户-登录

用户名:

密码:

用户-注册

用户名:

密码:

性别:男

女

爱好:篮球

足球

省份:

湖南

湖北

广东

广西

注册

登录

4.web.XML配置

Day27_Tomcat_Servlet

welcome.html

index.htm

index.jsp

default.html

default.htm

default.jsp

aa

com.qf.servlet.HelloServlet

aa

/bb

StandardServlet

StandardServlet

com.qf.servlet.StandardServlet

StandardServlet

/StandardServlet

RegisterServlet

RegisterServlet

com.qf.servlet2.RegisterServlet

RegisterServlet

/RegisterServlet

LoginServlet

LoginServlet

com.qf.servlet2.LoginServlet

LoginServlet

/LoginServlet