解决getWriter() has already been called for this response异常

 

Exception code

    @Autowired
    private HttpServletRequest request;
    @Autowired
    private HttpServletResponse response;


private void setResponse(String msg) throws IOException {
        response.setCharacterEncoding("UTF-8");
        response.setContentType("application/json; charset=utf-8");
        PrintWriter out = response.getWriter();
        JSONObject res = new 
        res.put("error_code", ResponseCode.ERROR.getCode());
        res.put("err_msg", msg);
        res.put("data", null);
        out.append(res.toString())
        out.flush();
        out.close();
        throw new ForbiddenException();
    }

Report an exception

getWriter() has already been called for this response

 

The solution is as follows

    @Autowired
    private HttpServletRequest request;
    @Autowired
    private HttpServletResponse response;


private void setResponse(String msg) throws IOException {
        response.setCharacterEncoding("UTF-8");
        response.setContentType("application/json; charset=utf-8");
        ServletOutputStream out = response.getOutputStream();
        try {
            JSONObject res = new JSONObject();
            res.put("error_code", ResponseCode.ERROR.getCode());
            res.put("err_msg", msg);
            res.put("data", null);
            String json = new ObjectMapper().writeValueAsString(res);
            out.write(json.getBytes());
            out.flush();
            out.close();
            throw new ForbiddenException();
        }finally {
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

Note that printwriter should not be used, try catch, close the stream in finally,