使用servlet重定向请求并且"setHeader"方法不起作用

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("/redirect")
public class RedirectServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // 设置响应头信息
        response.setHeader("Custom-Header", "Custom-Value");

        // 重定向请求
        response.sendRedirect("http://www.example.com");
    }
}