javaweb项目自定义HTTP请求Response返回JSON数据

//   全局异常拦截（拦截项目中的NotLoginException异常）
@ExceptionHandler(NotLoginException.class)
public void handlerNotLoginException(NotLoginException nle, HttpServletRequest request, HttpServletResponse response)
        throws Exception {

  //错误信息
  String message "错误";
  // 返回给前端
  String jsonString = "{\"success\":false,\"code\":404,\"message\":\""+message+"\"}";
  response.setCharacterEncoding("utf-8");
  response.setStatus(404);
  response.setContentType("application/json; charset=utf-8");
  PrintWriter writer = response.getWriter();
  writer.write(jsonString);
}