如何在 Spring Boot Filter 中从 servletResponse 获取响应正文

Question

我想在传递给客户端之前Response Body从中ServletResponse生成哈希签名。我找不到办法做到这一点。为了从中获取请求正文，ServletRequest 我实现了如下所示：

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

public class RequestWrapper extends HttpServletRequestWrapper{

    private final String body;
     
    public RequestWrapper(HttpServletRequest request) throws IOException 
    {
        //So that other request method behave just like before
        super(request);
         
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = null;
        try {
            InputStream inputStream = request.getInputStream();
            if (inputStream != null) {
                bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                char[] charBuffer = new char[128];
                int bytesRead = -1;
                while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                    stringBuilder.append(charBuffer, 0, bytesRead);
                }
            } else {
                stringBuilder.append("");
            }
        } catch (IOException ex) {
            throw ex;
        } finally {
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                } catch (IOException ex) {
                    throw ex;
                }
            }
        }
        //Store request pody content in 'body' variable 
        body = stringBuilder.toString();
    }
 
    @Override
    public ServletInputStream getInputStream() throws IOException {
        final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes());
        ServletInputStream servletInputStream = new ServletInputStream() {
            public int read() throws IOException {
                return byteArrayInputStream.read();
            }

            @Override
            public boolean isFinished() {

                return false;
            }

            @Override
            public boolean isReady() {

                return false;
            }

            @Override
            public void setReadListener(ReadListener listener) {

                
            }
        };
        return servletInputStream;
    }
 
    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(this.getInputStream()));
    }
 
    //Use this method to read the request body N times
    public String getBody() {
        return this.body;
    }
}

我怎样才能做类似的事情ServletResponse？

Answer 1

我在过滤器中实现了从以下位置ContentCachingResponseWrapper获取响应正文：ServletResponse

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

        ContentCachingResponseWrapper responseCacheWrapperObject = new ContentCachingResponseWrapper((HttpServletResponse) servletResponse);
        filterChain.doFilter(servletRequest, responseCacheWrapperObject);

        byte[] responseArray = responseCacheWrapperObject.getContentAsByteArray();
        String responseStr = new String(responseArray, responseCacheWrapperObject.getCharacterEncoding());
        //....use responsestr to make the signature

        responseCacheWrapperObject.copyBodyToResponse();
    }