Filter自定义过滤器

最近接触到filter过滤器，之前都没有接触到，这次在组长大人得帮助下对filter过滤器有了一点概念，组长大人还给了一个例子，记录一下。

@Configuration
public class SpringMvcConfig implements WebMvcConfigurer {
    @Bean
    public FilterRegistrationBean filterRegist() {
        FilterRegistrationBean frBean = new FilterRegistrationBean();
        //定义一个 ParamterFilter过滤器
        frBean.setFilter(new ParamterFilter());
        //需要拦截的地址
        frBean.addUrlPatterns("/cxf/*");
        //设置注册名称，若没有指定，使用bean名称
        frBean.setName("WebAsscessFilterMVC");
        return frBean;
    }
}

@Component
public class ParamterFilter extends OncePerRequestFilter {
    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        if(HttpMethod.POST.equals(HttpMethod.resolve(request.getMethod()))){
        //调用封装好的一个Wrapper
            PostRequestWrapper postRequestWrapper = new PostRequestWrapper(request);
            wirteLog(postRequestWrapper,response);
            filterChain.doFilter(postRequestWrapper,response);
        }else {
            wirteLog(request,response);
            filterChain.doFilter(request,response);
        }
    }
    protected void wirteLog(HttpServletRequest request, HttpServletResponse response) throws IOException {
        InputStream inputStream = request.getInputStream();
        ByteArrayOutputStream result = new ByteArrayOutputStream();
        byte[] buf = new byte[2048];
        int len = 0;
        while((len=inputStream.read(buf))>0){
            result.write(buf,0,len);
        }
        logger.debug(result.toString());
    }
}

public class PostRequestWrapper extends HttpServletRequestWrapper {
    private Logger logger = LoggerFactory.getLogger(PostRequestWrapper.class);
    private final byte[] bodyData;
    /**
     * Constructs a request object wrapping the given request.
     *
     * @param request The request to wrap
     * @throws IllegalArgumentException if the request is null
     */
    public PostRequestWrapper(HttpServletRequest request) {
        super(request);
        bodyData = getByteFromRequest(request);
    }

    /**
     * 获取Body中的字符中表示
     * @return
     */
    public String getBodyString() {
        if(bodyData != null && bodyData.length>0){
            return new String(bodyData);
        }
        return null;
    }

    /**
     *从Body体中获取数据并保存
     * @param request
     * @return
     */
    protected byte[] getByteFromRequest(HttpServletRequest request){
        ByteArrayOutputStream result = new ByteArrayOutputStream();
        try {
            //BufferedReader reader = new BufferedReader(new InputStreamReader(request.getInputStream()));
            byte[] buf = new byte[2048];
            int len = 0;
            while ((len=request.getInputStream().read(buf))>0){
                result.write(buf,0,len);
            }
        } catch (IOException e) {
            logger.error("{}",e);
        }
        return result.toByteArray();
    }
    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {

        final ByteArrayInputStream inputStream = new ByteArrayInputStream(bodyData);

        return new ServletInputStream() {
            @Override
            public int read() throws IOException {
                return inputStream.read();
            }
            @Override
            public boolean isFinished() {
                return false;
            }
            @Override
            public boolean isReady() {
                return false;
            }
            @Override
            public void setReadListener(ReadListener readListener) {
            }
        };
    }
}

这样就ok啦，就能在日志中查看到拦截信息。
知识嘛，慢慢积累，就好啦。