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
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h2>用户-登录</h2>
<form action="LoginServlet" method="post">
用户名:<input type="text" name="username" /><br/>
密码:<input type="password" name="password" /><br/>
<input type="submit" value="提交" />
</form>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h2>用户-注册</h2>
<!-- action属性：跳转页面或者映射路径
method属性：默认为doget请求
-->
<form action="RegisterServlet" method="post">
<!-- name属性：参数名,value属性，参数值-->
用户名:<input type="text" name="username" /><br/>
密码:<input type="password" name="password" /><br/>
性别:<input type="radio" name="sex" value="man" />男
<input type="radio" name="sex" value="woman" />女<br/>
爱好:<input type="checkbox" name="loves" value="basketball" />篮球
<input type="checkbox" name="loves" value="football" />足球<br/>
省份:<select name="province">
<option value="hunan">湖南</option>
<option value="hubei">湖北</option>
<option value="guangdong">广东</option>
<option value="guangxi">广西</option>
</select><br/>
<input type="submit" value="提交" />
</form>
</body>
</html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<a href="register.html">注册</a>
<a href="login.html">登录</a>
</body>
</html>
4.web.XML配置
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>Day27_Tomcat_Servlet</display-name>
<welcome-file-list>
<welcome-file>welcome.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>aa</servlet-name>
<servlet-class>com.qf.servlet.HelloServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>aa</servlet-name>
<url-pattern>/bb</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>StandardServlet</display-name>
<servlet-name>StandardServlet</servlet-name>
<servlet-class>com.qf.servlet.StandardServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>StandardServlet</servlet-name>
<url-pattern>/StandardServlet</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>RegisterServlet</display-name>
<servlet-name>RegisterServlet</servlet-name>
<servlet-class>com.qf.servlet2.RegisterServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>RegisterServlet</servlet-name>
<url-pattern>/RegisterServlet</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>LoginServlet</display-name>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>com.qf.servlet2.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>
</web-app>
