Java 后台多次獲取requestBody

如今越來越多的項目基於Springboot進行開發，在項目中攔截器的使用是不可缺少的，因為需要對body中的值進行校驗，例如加密驗簽、防重復提交、內容校驗等等，對於可以多次讀取body的解決方案如下：

1 新建HttpRequestWrapperUtil

public class HttpRequestWrapperUtil {
    public static String getBodyString(HttpServletRequest request) throws IOException {
        StringBuilder sb = new StringBuilder();
        InputStream inputStream = null;
        BufferedReader reader = null;
        try {
            inputStream = request.getInputStream();
            reader = new BufferedReader(new InputStreamReader(inputStream, Charset.forName("UTF-8")));
            String line = "";
            while ((line = reader.readLine()) != null) {
                sb.append(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return sb.toString();
    }
}

2 新建RequestReaderHttpServletRequestWrapper

public class RequestReaderHttpServletRequestWrapper extends HttpServletRequestWrapper{

    private final byte[] body;

    public RequestReaderHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        body = HttpRequestWrapperUtil.getBodyString(request).getBytes(Charset.forName("UTF-8"));
    }

    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {

        final ByteArrayInputStream bais = new ByteArrayInputStream(body);

        return new ServletInputStream() {

            @Override
            public int read() throws IOException {
                return bais.read();
            }

            @Override
            public boolean isFinished() {
                return false;
            }

            @Override
            public boolean isReady() {
                return false;
            }

            @Override
            public void setReadListener(ReadListener readListener) {

            }
        };
    }
}

3 新建HttpServletRequestReplacedFilter（過濾器）

public class HttpServletRequestReplacedFilter implements Filter {
    @Override
    public void destroy() {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
                         FilterChain chain) throws IOException, ServletException {
        ServletRequest requestWrapper = null;
        if(request instanceof HttpServletRequest) {
            requestWrapper = new RequestReaderHttpServletRequestWrapper((HttpServletRequest) request);
        }
        //獲取請求中的流如何，將取出來的字符串，再次轉換成流，然后把它放入到新request對象中。
        // 在chain.doFiler方法中傳遞新的request對象
        if(requestWrapper == null) {
            chain.doFilter(request, response);
        } else {
            chain.doFilter(requestWrapper, response);
        }
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {

    }
}

這樣就可以重復讀取body中的內容了