Question

我在写入HttpServletResponse之前尝试加密响应数据，所以我实现了自定义响应包装器和输出streram以及过滤器类，

问题是我需要加密整个响应数据一次，但没有write(String content)方法，但ServletOutputStream类中有三种方法可用write(int b)，write(byte[] b)和{{ 1}}当我运行应用程序时，只有一个方法被称为write(byte[] b, int off, int len)。

那么是否有任何解决方法可以将整个响应数据作为字符串，我可以调用encrypt（responseData）？

我的课程如下：

write(int b)

和

public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {

        HttpServletRequest httpServletRequest = (HttpServletRequest)request;
        HttpServletResponse httpServletResponse = (HttpServletResponse)response;
        BufferedRequestWrapper bufferedReqest = new BufferedRequestWrapper(httpServletRequest);  
        BufferedServletResponseWrapper bufferedResponse = new BufferedServletResponseWrapper(httpServletResponse);

        // pass the wrappers on to the next entry
        chain.doFilter(bufferedReqest, bufferedResponse);
}

我的自定义输出流类看起来像：

public class BufferedServletResponseWrapper extends HttpServletResponseWrapper {

    private final Logger LOG = LoggerFactory.getLogger(getClass());

    private ServletOutputStream outputStream;
    private PrintWriter writer;
    private MyServletOutputStream copier;

    public BufferedServletResponseWrapper(HttpServletResponse response) throws IOException {        
        super(response);
    }

    @Override
    public ServletOutputStream getOutputStream() throws IOException {
        LOG.info("getOutputStream");
        if (writer != null) {
            throw new IllegalStateException("getWriter() has already been called on this response.");
        }

        if (outputStream == null) {
            outputStream = getResponse().getOutputStream();
            copier = new MyServletOutputStream(outputStream);
        }

        return copier;
    }

    @Override
    public PrintWriter getWriter() throws IOException {
        LOG.info("getWriter");
        if (outputStream != null) {
            throw new IllegalStateException("getOutputStream() has already been called on this response.");
        }

        if (writer == null) {
            copier = new MyServletOutputStream(getResponse().getOutputStream());
            writer = new PrintWriter(new OutputStreamWriter(copier, getResponse().getCharacterEncoding()), true);
        }

        return writer;
    }

    @Override
    public void flushBuffer() throws IOException {
        if (writer != null) {
            writer.flush();
        } else if (outputStream != null) {
            copier.flush();
        }
    }

    public byte[] getCopy() {
        if (copier != null) {
            return copier.getCopy();
        } else {
            return new byte[0];
        }
    }

}

Answer 1

String str = new String（bufferedResponse .getCopy（））;

这将为您提供outputStream中的数据字符串。我可以在你的代码中看到你正在写字节和复印机。此复印机也可以在以后修改。

String encStr=Encrypt(str); // your encryption logic.

ServletOutputStream out= response.getOutputStream();

out.write(encStr.getByte()); //adding your encrypted data to response 
out.flush();
out.close();

Answer 2

我通过这种方式解决了这个问题：

在响应包装器类中创建了一个自定义的ByteArrayOutputStream和PrintWriter实例。
修改了getOutputStream（）和getWriter（）方法，以使用在步骤1中创建的自定义实例。
最后，在doFilter（）语句之后的过滤器中，从自定义编写器和输出流中检索响应数据。并将加密数据写入原始回复。

这里是响应包装器的样子：

public class BufferedServletResponseWrapper extends HttpServletResponseWrapper {

        private final Logger LOG = LoggerFactory.getLogger(getClass());

    private ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
    private PrintWriter writer = new PrintWriter(outputStream);

    public BufferedServletResponseWrapper(HttpServletResponse response)
            throws IOException {
        super(response);
    }

    @Override
    public ServletOutputStream getOutputStream() throws IOException {
        LOG.info("getOutputStream");

        return new ServletOutputStream() {
            @Override
            public void write(int b) throws IOException {
                LOG.info("write int");

                outputStream.write(b);
            }

            @Override
            public void write(byte[] b) throws IOException {
                LOG.info("write byte[]");

                outputStream.write(b);
            }
        };
    }

    @Override
    public PrintWriter getWriter() throws IOException {
        LOG.info("getWriter");
        return writer;
    }

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

    public String getResponseData() {
        return outputStream.toString();
    }

}

和doFilter（）看起来像：

public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {

        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        BufferedServletResponseWrapper bufferedResponse = new BufferedServletResponseWrapper(
                httpServletResponse);

        // pass the wrappers on to the next entry
        chain.doFilter(httpServletRequest, bufferedResponse);

        String responseData = bufferedResponse.getResponseData();
        String encryptedResponseData = encrypt(responseData);
        OutputStream outputStream = httpServletResponse.getOutputStream();
        outputStream.write(encryptedResponseData.getBytes());
        outputStream.flush();
        outputStream.close();
    }

如何加密过滤器中的响应数据

2 个答案: