如何获取请求参数

表单如下：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <form action="http://localhost:8080/servlet/parameterServlet" method="get">
        用户名:<input type="text" name="username"><br>
        密码：<input type="password" name="password"><br>
        兴趣爱好：<input type="checkbox" name="hobby" value="cpp">cpp
        <input type="checkbox" name="hobby" value="java">java
        <input type="checkbox" name="hobby" value="js">javascript<br>
        <input type="submit">
    </form>
</body>
</html>

servlet程序如下：

package LWB;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Arrays;

public class ParameterServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String username=req.getParameter("username");
        String password=req.getParameter("password");
        String[] hobby=req.getParameterValues("hobby");
        System.out.println("用户名："+username);
        System.out.println("密码："+password);
        System.out.println("兴趣爱好："+ Arrays.asList(hobby));
    }
}