这个应该怎么实现？想让前端直接执行这条语句

Question

StringBuilder builder = new StringBuilder();
builder.append("alert('你的帐号已在别处登陆，你被强迫下线！');window.location.href='login.jsp';");

Answer 1

response.setCharacterEncoding("utf-8");
PrintWriter out = response.getWriter();
out.print("<script>alert('你的帐号已在别处登陆，你被强迫下线！'); window.location='login.jsp' </script>");
out.flush();
out.close();