已知注册过的用户名存储在数组中,请用Ajax实现注册验证用户名有效性问题。(不重复就有效),要求用户检查用servlet实现。
时间: 2024-02-03 12:11:45 浏览: 33
以下是一个简单的实现:
1. 编写前端页面,让用户输入用户名并点击“验证”按钮:
```
<!DOCTYPE html>
<html>
<head>
<title>注册验证</title>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
</head>
<body>
<h1>注册验证</h1>
<label>用户名:</label>
<input type="text" id="username" name="username">
<button id="checkBtn">验证</button>
<p id="result"></p>
<script>
$(document).ready(function() {
$('#checkBtn').click(function() {
var username = $('#username').val();
$.ajax({
url: 'checkUsername',
type: 'POST',
data: {username: username},
success: function(response) {
$('#result').text(response.message);
}
});
});
});
</script>
</body>
</html>
```
2. 编写Servlet,在其中处理Ajax请求并返回验证结果:
```
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/checkUsername")
public class CheckUsernameServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
// 已注册的用户名数组
private static final String[] REGISTERED_USERNAMES = {"user1", "user2", "user3"};
public CheckUsernameServlet() {
super();
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String username = request.getParameter("username");
boolean isValid = true;
for (String registeredUsername : REGISTERED_USERNAMES) {
if (registeredUsername.equals(username)) {
isValid = false;
break;
}
}
String message = isValid ? "用户名有效" : "用户名已存在";
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
response.getWriter().write("{\"message\": \"" + message + "\"}");
}
}
```
3. 在web.xml中配置Servlet:
```
<web-app>
<servlet>
<servlet-name>CheckUsernameServlet</servlet-name>
<servlet-class>com.example.CheckUsernameServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>CheckUsernameServlet</servlet-name>
<url-pattern>/checkUsername</url-pattern>
</servlet-mapping>
</web-app>
```
以上就是一个简单的实现,当用户输入用户名并点击“验证”按钮时,前端通过Ajax向服务器发送请求,服务器接收请求并通过遍历已注册的用户名数组来判断该用户名是否已存在,最后返回验证结果。前端收到服务器返回的结果后将其显示在页面上。
相关推荐
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![rar](https://img-home.csdnimg.cn/images/20210720083606.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)