HttpServletResponseWrapper包装HttpServletResponse 后无法正常响应

蔚落 2022-09-14 08:59 175阅读 0赞

目的想通过过滤器修改响应中的参数，发现包装后无法正常响应，从浏览器请求后浏览器一直在转圈圈持续很久

HttpServletResponseWrapper

public class Response2Wrapper extends HttpServletResponseWrapper {
    
        private ByteArrayOutputStream output;
    
        private ServletOutputStream filterOutput;
    
        public Response2Wrapper(HttpServletResponse response) {
            super(response);
            output = new ByteArrayOutputStream();
        }
    
    
        @Override
        public ServletOutputStream getOutputStream() throws IOException {
            if (filterOutput == null) {
                filterOutput = new ServletOutputStream() {
                    @Override
                    public void write(int b) throws IOException {
                        output.write(b);
                    }
    
                    @Override
                    public boolean isReady() {
                        return false;
                    }
    
                    @Override
                    public void setWriteListener(WriteListener writeListener) {
                    }
                };
            }
            return filterOutput;
        }
    
        public byte[] toByteArray() {
            return output.toByteArray();
        }
    }

ServletParamaterFilter

public class ServletParamaterFilter implements Filter {
    
    
    
        @Override
        public void destroy() {
        }
    
        @Override
        public void doFilter(ServletRequest request, ServletResponse response,
                             FilterChain chain) throws IOException, ServletException {
    
            if (request instanceof HttpServletRequest && response instanceof HttpServletResponse) {
                System.out.println("=====ServletParamaterFilter=====");
                //转换成代理类
                Response2Wrapper wrapperResponse = new Response2Wrapper((HttpServletResponse) response);
                // 这里只拦截返回，直接让请求过去，如果在请求前有处理，可以在这里处理
                chain.doFilter(request, wrapperResponse);
                PrintWriter out = response.getWriter();
                //response.setContentLength("test".getBytes().length);
                out.write("test");
                out.flush();
                out.close();
            } else {
                chain.doFilter(request, response);
            }
    
        }
    
        @Override
        public void init(FilterConfig filterConfig) {
            System.out.println("ServletParamaterFilter初始化创建....");
        }
    
    
    }

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAVGFuZ19fVmk_size_20_color_FFFFFF_t_70_g_se_x_16][]

通过不短的查找调试，原来是没有给包装后的response设置对应的内容长度

>     response.setContentLength("test".getBytes().length);
> 
> 问题解决

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