用java写一段可以判断用户请求是ios还是mac还是window的代码

可以使用user-agent来判断用户请求的设备类型，以下是用Java实现的示例代码：

import javax.servlet.http.HttpServletRequest;

public class UserAgentUtil {

    public static String getOs(HttpServletRequest request) {
        String userAgent = request.getHeader("User-Agent");
        String os = "";

        if (userAgent.toLowerCase().contains("windows")) {
            os = "Windows";
        } else if (userAgent.toLowerCase().contains("mac")) {
            os = "Mac";
        } else if (userAgent.toLowerCase().contains("iphone") || userAgent.toLowerCase().contains("ipad") || userAgent.toLowerCase().contains("ipod")) {
            os = "iOS";
        }

        return os;
    }

}

在Servlet中调用该方法，即可获取用户请求的设备类型：

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

public class MyServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();

        String os = UserAgentUtil.getOs(request);
        out.println("您的设备类型为：" + os);
    }
}