在异常映射器中检索请求主体

Question

我正在尝试在JAX-RS ExceptionMapper中检索请求的主体.到目前为止,这是我的代码:

@Provider @Componenet
public class BaseExceptionMapper implements ExceptionMapper<Exception> {

    @Context private HttpServletRequest request;

    @Override
    public Response toResponse(Exception ex) {

        // Trying to retrieve request body for logging throws an error
        String requestBody = IOUtils.toString(request.getInputStream());

    }

}

所以我的困境是我无法获取日志记录的请求体,因为servlet API不允许你多次为请求调用request.getInputStream()/ request.getReader()(并且JAX-RS显然是在调用它解析请求).有谁知道是否有办法做我想做的事情？

Answer 1

这个问题有点老了,但答案仍然可以帮助别人.我的例子也取决于Commons-Io.

您可以创建ContainerRequestFilter并使用TeeInputStream代理/复制原始InputStream:

@Provider
@Priority(Priorities.ENTITY_CODER)
public class CustomRequestWrapperFilter implements ContainerRequestFilter { 

    @Override
    public void filter(ContainerRequestContext requestContext)
            throws IOException {
        ByteArrayOutputStream proxyOutputStream = new ByteArrayOutputStream();
        requestContext.setEntityStream(new TeeInputStream(requestContext.getEntityStream(), proxyOutputStream));
        requestContext.setProperty("ENTITY_STREAM_COPY", proxyOutputStream);
    }

}

并在ExceptionMapper中使用@Inject和javax.inject.Provider来获取注入的ContainerRequest.

ExceptionMapper看起来像这样:

@Provider
public class BaseExceptionMapper implements ExceptionMapper<Exception> {

    @Inject
    private javax.inject.Provider<ContainerRequest> containerRequestProvider;

    @Override
    public Response toResponse(Exception exception) {
        ByteArrayOutputStream bos = (ByteArrayOutputStream) containerRequestProvider
                .get().getProperty("ENTITY_STREAM_COPY");
        String requestBody = bos.toString();
        ...
    }

}

当我还使用了@Component注释时,没有使用我的ExceptionMapper.我认为@Provider就足够了.

Answer 2

一种可能的解决方案是使用 servlet 过滤器并包装请求，这允许您拦截对请求输入流的读取调用。伪代码示例（取决于commons-io）：

import org.apache.commons.io.output.StringBuilderWriter;
import org.apache.commons.io.input.TeeInputStream;
class MyHttpRequest extends HttpServletRequestWrapper {
    private StringBuilderWriter myString = new StringBuilderWriter();
    private InputStream myIn;
    public MyHttpRequest(HttpServletRequest request) {
        super(request);
        myIn = new TeeInputStream(request.getInputStream(), myString);
    }
    @Override public ServletInputStream getInputStream()
            throws java.io.IOException {
        // this will need an extra wrapper to compile
        return myIn;
    }
    public String getRequestBody() {
        return myString.toString();
    }
}

筛选：

public void doFilter(ServletRequest request, ServletResponse response,
        FilterChain chain) throws IOException, ServletException {
    MyHttpRequest wrapper = new MyHttpRequest((HttpServletRequest) request);
    chain.doFilter(wrapper, response, chain);
}

映射器：

@Context private HttpServletRequest request;
@Override public Response toResponse(Exception ex) {
    String body = "";
    if (this.request instanceof MyHttpRequest) {
        body = ((MyHttpRequest)request).getRequestBody()
    }
}

您需要一个包装类ServletInputStream，您可以在此处找到示例实现：修改 HttpServletRequest body