如何在Spring拦截器中读取httpservletresponse？

Question

I'm working on task that log api request and response in database. I need to autowire spring beans to access database and we can not autowire spring beans inside filter.

Problem is we can read response multiple times only in filter using HttpServletResponseWrapper.

Is there any way to read response multiple times in spring interceptor?

Here is my code using Filter . It can retrieve all information but can't autowire beans in ApiActivityManager to insert data in database.

If I read response in Interceptor once then in controller response is null.

public class ApiActivityInterceptor implements Filter {
    ApiActivityManager apiActivityManager = new ApiActivityManager();

    @Override public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override 
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        MyRequestWrapper requestWrapper = new MyRequestWrapper((HttpServletRequest)request);
        MyResponseWrapper responseWrapper = new MyResponseWrapper((HttpServletResponse)response);
        InputStream inputStream = requestWrapper.getInputStream();
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = null;
        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("");
        }
        String requestText = stringBuilder.toString();
        log.info(requestText);

        chain.doFilter((ServletRequest)requestWrapper,(ServletResponse)responseWrapper);

        String responseText = new String(responseWrapper.getCopy(),responseWrapper.getCharacterEncoding());
        log.info(responseText);
        //for log details in database
        activityLogDetails.setActivityLog(requestText,responseText);
    }

    @Override public void destroy() {

    }
}

Thanks

Answer 1

To autowire spring beans in the filter class,

1. first add @Component annotation in your filter class.
2. Register filter with filter name as bean name and filter class as org.springframework.web.filter.DelegatingFilterProxy

So my solution is looks like,

ApiActivityFilter.java

@Component("apiActivityFilter")
public class ApiActivityFilter implements Filter {

    @Autowired
    ApiActivityManager apiActivityManager;

    @Override public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override 
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        MyRequestWrapper requestWrapper = new MyRequestWrapper((HttpServletRequest)request);
        MyResponseWrapper responseWrapper = new MyResponseWrapper((HttpServletResponse)response);
        InputStream inputStream = requestWrapper.getInputStream();
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = null;
        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("");
        }
        String requestText = stringBuilder.toString();
        log.info(requestText);

        chain.doFilter((ServletRequest)requestWrapper,(ServletResponse)responseWrapper);

        String responseText = new String(responseWrapper.getCopy(),responseWrapper.getCharacterEncoding());
        log.info(responseText);
        //for log details in database
        apiActivityManager.logApiActivity(activityLog);//activityLog Object to be logged
    }

    @Override public void destroy() {

    }
}

Register filter using Java config

FilterRegistration.Dynamic apiActivityFilter = servletContext.addFilter("apiActivityFilter", DelegatingFilterProxy.class);
apiActivityFilter.addMappingForUrlPatterns(null, true, "/api/*");

Register filter using XML config

<filter>
  <filter-name>apiActivityFilter</filter-name>
  <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>

<filter-mapping>
  <filter-name>apiActivityFilter</filter-name>
  <url-pattern>/api/*</url-pattern>
</filter-mapping>