1. 需求: 如果用户名存在, 则登录成功. 不存在, 则失败.
2. 在login.jsp中:
<form action ="login_do.jsp" method ="post">
用户名: <input type="text" name="username"/><br/>
密码: <input type="password" name="password"/><br/>
<input type = "submit" value="我要登录!"/>
</form>
用户点击登录时, 跳转到login_do.jsp, 来处理登录的请求
3. 在 login_do中:
<%
String username = request.getParameter("username");
String password = request.getParameter("password");
%>
4. 在DBUtil.java中:
public static User verifyAccount(String username, String password) {
if(db.containsKey(username)) {
User user = db.get(username);
if(user.getPassword().equals(password)) {
return user;
}else {
return null;
}
}
return null;
}
5. 在 login_do中:
<%
String username = request.getParameter("username");
String password = request.getParameter("password");
User user = DBUtil.verifyAccount(username,password);
if(user == null){
out.println("很遗憾, 登录失败, 用户名或密码错误!");
}else{
out.println("恭喜你!登录成功了!");
}
%>
6. 效果