Filter过滤请求，处理请求头及返回数据

闲话少说，上代码：

代理类，主要为过滤Response返回数据：

public class ResponseWrapper extends HttpServletResponseWrapper {

    private ByteArrayOutputStream buffer;

    private ServletOutputStream out;

    public ResponseWrapper(HttpServletResponse httpServletResponse) {
        super(httpServletResponse);
        buffer = new ByteArrayOutputStream();
        out = new WrapperOutputStream(buffer);
    }

    @Override
    public ServletOutputStream getOutputStream()
            throws IOException {
        return out;
    }

    @Override
    public void flushBuffer()
            throws IOException {
        if (out != null) {
            out.flush();
        }
    }

    public byte[] getContent()
            throws IOException {
        flushBuffer();
        return buffer.toByteArray();
    }

    class WrapperOutputStream extends ServletOutputStream {
        private ByteArrayOutputStream bos;

        public WrapperOutputStream(ByteArrayOutputStream bos) {
            this.bos = bos;
        }

        @Override
        public void write(int b)
                throws IOException {
            bos.write(b);
        }

        @Override
        public boolean isReady() {

            // TODO Auto-generated method stub
            return false;

        }

        @Override
        public void setWriteListener(WriteListener arg0) {

            // TODO Auto-generated method stub

        }
    }

}

 @Override
    public void destroy() {

    }

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
		//request可对请求头做处理
        String uri = request.getRequestURI();
        //由于项目包含静态资源 代理类处理之后静态资源返回错误 出此下策
        if (uri.endsWith(".html")) {
            filterChain.doFilter(request, response);
            return;
        }
        ResponseWrapper wrapperResponse = new ResponseWrapper(response);//转换成代理类
        wrapperResponse.setContentType(response.getContentType());
        filterChain.doFilter(request, wrapperResponse);
        byte[] content = wrapperResponse.getContent();//获取返回值
        AppUser user = (AppUser) RequestAuth.getUser(request);
        //判断是否有值
        if (content.length > 0) {
			//返回信息
            String str = new String(content, "UTF-8");
            String ciphertext = null;

            try {
                //......根据需要处理返回值
                
            } catch (Exception e) {
                e.printStackTrace();
            }
            //把返回值输出到客户端
            ServletOutputStream out = response.getOutputStream();
            if (ciphertext != null) {
            	//这句必须加 不加会导致请求保留 响应时间非常久 返回需保持两个response长度保持一致
                response.setContentLength(ciphertext.getBytes().length);
                out.write(ciphertext.getBytes());
            }
            out.flush();
            out.close();
        }
    }