Question

我正在尝试访问Java Servlet过滤器中的两个http请求参数，这里没什么新东西，但很惊讶地发现参数已经被消耗了！因此，它在过滤链中不再可用。

似乎只有当参数进入POST请求主体（例如表单提交）时才会出现这种情况。

有没有办法读取参数而不消耗它们？

到目前为止，我只找到了这个引用：Servlet Filter using request.getParameter loses Form data。

谢谢！

Answer 1

另外，解决此问题的另一种方法是不使用过滤器链，而是构建自己的拦截器组件，可能使用可以在已解析的请求主体上运行的方面。它也可能更高效，因为您只需将请求InputStream转换为您自己的模型对象一次。

但是，我仍然认为想要多次读取请求主体是合理的，特别是当请求通过过滤器链时。我通常会使用过滤器链来进行某些操作，我希望将这些操作保留在HTTP层，与服务组件分离。

根据Will Hartung的建议，我通过扩展HttpServletRequestWrapper，使用请求InputStream并基本上缓存字节来实现此目的。

public class MultiReadHttpServletRequest extends HttpServletRequestWrapper {
  private ByteArrayOutputStream cachedBytes;

  public MultiReadHttpServletRequest(HttpServletRequest request) {
    super(request);
  }

  @Override
  public ServletInputStream getInputStream() throws IOException {
    if (cachedBytes == null)
      cacheInputStream();

      return new CachedServletInputStream();
  }

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

  private void cacheInputStream() throws IOException {
    /* Cache the inputstream in order to read it multiple times. For
     * convenience, I use apache.commons IOUtils
     */
    cachedBytes = new ByteArrayOutputStream();
    IOUtils.copy(super.getInputStream(), cachedBytes);
  }

  /* An inputstream which reads the cached request body */
  public class CachedServletInputStream extends ServletInputStream {
    private ByteArrayInputStream input;

    public CachedServletInputStream() {
      /* create a new input stream from the cached request body */
      input = new ByteArrayInputStream(cachedBytes.toByteArray());
    }

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

现在，在将原始请求传递给过滤器链之前，可以多次读取请求正文：

public class MyFilter implements Filter {
  @Override
  public void doFilter(ServletRequest request, ServletResponse response,
        FilterChain chain) throws IOException, ServletException {

    /* wrap the request in order to read the inputstream multiple times */
    MultiReadHttpServletRequest multiReadRequest = new MultiReadHttpServletRequest((HttpServletRequest) request);

    /* here I read the inputstream and do my thing with it; when I pass the
     * wrapped request through the filter chain, the rest of the filters, and
     * request handlers may read the cached inputstream
     */
    doMyThing(multiReadRequest.getInputStream());
    //OR
    anotherUsage(multiReadRequest.getReader());
    chain.doFilter(multiReadRequest, response);
  }
}

此解决方案还允许您通过getParameterXXX方法多次读取请求正文，因为基础调用是getInputStream()，这当然会读取缓存的请求InputStream。< / p>

修改

适用于较新版本的ServletInputStream界面。您需要提供更多方法的实现，例如isReady，setReadListener等。请参阅下面评论中提供的question。

Answer 2

我知道我已经迟到了，但这个问题对我来说仍然很重要，这个SO帖子是谷歌的热门歌曲之一。我要继续发布我的解决方案，希望别人可以节省几个小时。

在我的情况下，我需要记录所有请求和响应与他们的身体。使用Spring Framework，答案实际上非常简单，只需使用ContentCachingRequestWrapper和ContentCachingResponseWrapper。

import org.springframework.web.util.ContentCachingRequestWrapper;
import org.springframework.web.util.ContentCachingResponseWrapper;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class LoggingFilter implements Filter {

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

    }

    @Override
    public void destroy() {

    }

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

        ContentCachingRequestWrapper requestWrapper = new ContentCachingRequestWrapper((HttpServletRequest) request);
        ContentCachingResponseWrapper responseWrapper = new ContentCachingResponseWrapper((HttpServletResponse) response);

        try {
            chain.doFilter(requestWrapper, responseWrapper);
        } finally {

            String requestBody = new String(requestWrapper.getContentAsByteArray());
            String responseBody = new String(responseWrapper.getContentAsByteArray());
            // Do not forget this line after reading response content or actual response will be empty!
            responseWrapper.copyBodyToResponse();

            // Write request and response body, headers, timestamps etc. to log files

        }

    }

}

Answer 3

唯一的方法是让你自己在过滤器中使用整个输入流，从中获取你想要的内容，然后为你读取的内容创建一个新的InputStream，并将该InputStream放入ServletRequestWrapper（或者了HttpServletRequestWrapper）。

缺点是你必须自己解析有效载荷，标准不能让你有这种能力。

补遗 -

正如我所说，你需要看一下HttpServletRequestWrapper。

在过滤器中，您可以通过调用FilterChain.doFilter（请求，响应）继续。

对于普通过滤器，请求和响应与传递给过滤器的请求和响应相同。情况并非必须如此。您可以用自己的请求和/或回复替换它们。

HttpServletRequestWrapper专门用于促进这一点。您将原始请求传递给它，然后您可以拦截所有呼叫。您可以创建自己的子类，并将getInputStream方法替换为您自己的子类。您无法更改原始请求的输入流，因此您可以使用此包装并返回自己的输入流。

最简单的情况是将原始请求输入流用于字节缓冲区，对其执行任何魔术，然后从该缓冲区创建新的ByteArrayInputStream。这是包装器中返回的内容，它将传递给FilterChain.doFilter方法。

您需要为ServletInputStream创建子类，并为ByteArrayInputStream创建另一个包装器，但这也不是什么大问题。

Answer 4

上述答案非常有用，但在我的经验中仍然存在一些问题。在tomcat 7 servlet 3.0上，还必须覆盖getParamter和getParamterValues。这里的解决方案包括get-query参数和post-body。它允许轻松获取原始字符串。

与其他解决方案一样，它使用Apache commons-io和Googles Guava。

在此解决方案中，getParameter *方法不会抛出IOException，但它们使用super.getInputStream（）（获取正文），这可能会抛出IOException。我抓住它并抛出runtimeException。它不太好。

import com.google.common.collect.Iterables;
import com.google.common.collect.ObjectArrays;

import org.apache.commons.io.IOUtils;
import org.apache.http.NameValuePair;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.entity.ContentType;

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

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

/**
 * Purpose of this class is to make getParameter() return post data AND also be able to get entire
 * body-string. In native implementation any of those two works, but not both together.
 */
public class MultiReadHttpServletRequest extends HttpServletRequestWrapper {
    public static final String UTF8 = "UTF-8";
    public static final Charset UTF8_CHARSET = Charset.forName(UTF8);
    private ByteArrayOutputStream cachedBytes;
    private Map<String, String[]> parameterMap;

    public MultiReadHttpServletRequest(HttpServletRequest request) {
        super(request);
    }

    public static void toMap(Iterable<NameValuePair> inputParams, Map<String, String[]> toMap) {
        for (NameValuePair e : inputParams) {
            String key = e.getName();
            String value = e.getValue();
            if (toMap.containsKey(key)) {
                String[] newValue = ObjectArrays.concat(toMap.get(key), value);
                toMap.remove(key);
                toMap.put(key, newValue);
            } else {
                toMap.put(key, new String[]{value});
            }
        }
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        if (cachedBytes == null) cacheInputStream();
        return new CachedServletInputStream();
    }

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

    private void cacheInputStream() throws IOException {
    /* Cache the inputStream in order to read it multiple times. For
     * convenience, I use apache.commons IOUtils
     */
        cachedBytes = new ByteArrayOutputStream();
        IOUtils.copy(super.getInputStream(), cachedBytes);
    }

    @Override
    public String getParameter(String key) {
        Map<String, String[]> parameterMap = getParameterMap();
        String[] values = parameterMap.get(key);
        return values != null && values.length > 0 ? values[0] : null;
    }

    @Override
    public String[] getParameterValues(String key) {
        Map<String, String[]> parameterMap = getParameterMap();
        return parameterMap.get(key);
    }

    @Override
    public Map<String, String[]> getParameterMap() {
        if (parameterMap == null) {
            Map<String, String[]> result = new LinkedHashMap<String, String[]>();
            decode(getQueryString(), result);
            decode(getPostBodyAsString(), result);
            parameterMap = Collections.unmodifiableMap(result);
        }
        return parameterMap;
    }

    private void decode(String queryString, Map<String, String[]> result) {
        if (queryString != null) toMap(decodeParams(queryString), result);
    }

    private Iterable<NameValuePair> decodeParams(String body) {
        Iterable<NameValuePair> params = URLEncodedUtils.parse(body, UTF8_CHARSET);
        try {
            String cts = getContentType();
            if (cts != null) {
                ContentType ct = ContentType.parse(cts);
                if (ct.getMimeType().equals(ContentType.APPLICATION_FORM_URLENCODED.getMimeType())) {
                    List<NameValuePair> postParams = URLEncodedUtils.parse(IOUtils.toString(getReader()), UTF8_CHARSET);
                    params = Iterables.concat(params, postParams);
                }
            }
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }
        return params;
    }

    public String getPostBodyAsString() {
        try {
            if (cachedBytes == null) cacheInputStream();
            return cachedBytes.toString(UTF8);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    /* An inputStream which reads the cached request body */
    public class CachedServletInputStream extends ServletInputStream {
        private ByteArrayInputStream input;

        public CachedServletInputStream() {
            /* create a new input stream from the cached request body */
            input = new ByteArrayInputStream(cachedBytes.toByteArray());
        }

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

    @Override
    public String toString() {
        String query = dk.bnr.util.StringUtil.nullToEmpty(getQueryString());
        StringBuilder sb = new StringBuilder();
        sb.append("URL='").append(getRequestURI()).append(query.isEmpty() ? "" : "?" + query).append("', body='");
        sb.append(getPostBodyAsString());
        sb.append("'");
        return sb.toString();
    }
}

Answer 5

我也有同样的问题，我相信下面的代码更简单，它对我有用，

public class MultiReadHttpServletRequest extends  HttpServletRequestWrapper {

 private String _body;

public MultiReadHttpServletRequest(HttpServletRequest request) throws IOException {
   super(request);
   _body = "";
   BufferedReader bufferedReader = request.getReader();           
   String line;
   while ((line = bufferedReader.readLine()) != null){
       _body += line;
   }
}

@Override
public ServletInputStream getInputStream() throws IOException {
   final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(_body.getBytes());
   return new ServletInputStream() {
       public int read() throws IOException {
           return byteArrayInputStream.read();
       }
   };
}

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

过滤器java类中的

，

            HttpServletRequest properRequest = ((HttpServletRequest) req);
            MultiReadHttpServletRequest wrappedRequest = new MultiReadHttpServletRequest(properRequest);
            req = wrappedRequest;
            inputJson = IOUtils.toString(req.getReader());
            System.out.println("body"+inputJson);

如果您有任何疑问，请与我们联系

Answer 6

只是覆盖getInputStream()在我的情况下不起作用。我的服务器实现似乎解析参数而不调用此方法。我没有找到任何其他方法，但也重新实现了所有四个getParameter *方法。以下是getParameterMap的代码（使用Apache Http Client和Google Guava库）：

@Override
public Map<String, String[]> getParameterMap() {
    Iterable<NameValuePair> params = URLEncodedUtils.parse(getQueryString(), NullUtils.UTF8);

    try {
        String cts = getContentType();
        if (cts != null) {
            ContentType ct = ContentType.parse(cts);
            if (ct.getMimeType().equals(ContentType.APPLICATION_FORM_URLENCODED.getMimeType())) {
                List<NameValuePair> postParams = URLEncodedUtils.parse(IOUtils.toString(getReader()), NullUtils.UTF8);
                params = Iterables.concat(params, postParams);
            }
        }
    } catch (IOException e) {
        throw new IllegalStateException(e);
    }
    Map<String, String[]> result = toMap(params);
    return result;
}

public static Map<String, String[]> toMap(Iterable<NameValuePair> body) {
    Map<String, String[]> result = new LinkedHashMap<>();
    for (NameValuePair e : body) {
        String key = e.getName();
        String value = e.getValue();
        if (result.containsKey(key)) {
            String[] newValue = ObjectArrays.concat(result.get(key), value);
            result.remove(key);
            result.put(key, newValue);
        } else {
            result.put(key, new String[] {value});
        }
    }
    return result;
}

Answer 7

因此，这基本上是Lathy的答案，但已针对ServletInputStream的较新要求进行了更新。

即（对于ServletInputStream），必须实现：

public abstract boolean isFinished();

public abstract boolean isReady();

public abstract void setReadListener(ReadListener var1);

这是Lathy编辑的对象

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

public class RequestWrapper extends HttpServletRequestWrapper {

    private String _body;

    public RequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        _body = "";
        BufferedReader bufferedReader = request.getReader();
        String line;
        while ((line = bufferedReader.readLine()) != null){
            _body += line;
        }
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {

        CustomServletInputStream kid = new CustomServletInputStream(_body.getBytes());
        return kid;
    }

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

在某个地方（??），我找到了它（这是处理“额外”方法的一流类。

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;

public class CustomServletInputStream extends ServletInputStream {

    private byte[] myBytes;

    private int lastIndexRetrieved = -1;
    private ReadListener readListener = null;

    public CustomServletInputStream(String s) {
        try {
            this.myBytes = s.getBytes("UTF-8");
        } catch (UnsupportedEncodingException ex) {
            throw new IllegalStateException("JVM did not support UTF-8", ex);
        }
    }

    public CustomServletInputStream(byte[] inputBytes) {
        this.myBytes = inputBytes;
    }

    @Override
    public boolean isFinished() {
        return (lastIndexRetrieved == myBytes.length - 1);
    }

    @Override
    public boolean isReady() {
        // This implementation will never block
        // We also never need to call the readListener from this method, as this method will never return false
        return isFinished();
    }

    @Override
    public void setReadListener(ReadListener readListener) {
        this.readListener = readListener;
        if (!isFinished()) {
            try {
                readListener.onDataAvailable();
            } catch (IOException e) {
                readListener.onError(e);
            }
        } else {
            try {
                readListener.onAllDataRead();
            } catch (IOException e) {
                readListener.onError(e);
            }
        }
    }

    @Override
    public int read() throws IOException {
        int i;
        if (!isFinished()) {
            i = myBytes[lastIndexRetrieved + 1];
            lastIndexRetrieved++;
            if (isFinished() && (readListener != null)) {
                try {
                    readListener.onAllDataRead();
                } catch (IOException ex) {
                    readListener.onError(ex);
                    throw ex;
                }
            }
            return i;
        } else {
            return -1;
        }
    }
};

最终，我只是试图记录请求。上面的弗兰肯斯坦作品一起帮助我创建了下面的作品。

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.Principal;
import java.util.Enumeration;
import java.util.LinkedHashMap;
import java.util.Map;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.IOUtils;

//one or the other based on spring version
//import org.springframework.boot.autoconfigure.web.ErrorAttributes;
import org.springframework.boot.web.servlet.error.ErrorAttributes;

import org.springframework.core.Ordered;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.context.request.WebRequest;
import org.springframework.web.filter.OncePerRequestFilter;


/**
 * A filter which logs web requests that lead to an error in the system.
 */
@Component
public class LogRequestFilter extends OncePerRequestFilter implements Ordered {

    // I tried apache.commons and slf4g loggers.  (one or the other in these next 2 lines of declaration */
    //private final static org.apache.commons.logging.Log logger = org.apache.commons.logging.LogFactory.getLog(LogRequestFilter.class);
    private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(LogRequestFilter.class);

    // put filter at the end of all other filters to make sure we are processing after all others
    private int order = Ordered.LOWEST_PRECEDENCE - 8;
    private ErrorAttributes errorAttributes;

    @Override
    public int getOrder() {
        return order;
    }

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
            throws ServletException, IOException {

        String temp = ""; /* for a breakpoint, remove for production/real code */

        /* change to true for easy way to comment out this code, remove this if-check for production/real code */
        if (false) {
            filterChain.doFilter(request, response);
            return;
        }

        /* make a "copy" to avoid issues with body-can-only-read-once issues */
        RequestWrapper reqWrapper = new RequestWrapper(request);

        int status = HttpStatus.INTERNAL_SERVER_ERROR.value();
        // pass through filter chain to do the actual request handling
        filterChain.doFilter(reqWrapper, response);
        status = response.getStatus();

        try {
            Map<String, Object> traceMap = getTrace(reqWrapper, status);
            // body can only be read after the actual request handling was done!
            this.getBodyFromTheRequestCopy(reqWrapper, traceMap);

            /* now do something with all the pieces of information gatherered */
            this.logTrace(reqWrapper, traceMap);
        } catch (Exception ex) {
            logger.error("LogRequestFilter FAILED: " + ex.getMessage(), ex);
        }
    }

    private void getBodyFromTheRequestCopy(RequestWrapper rw, Map<String, Object> trace) {
        try {
            if (rw != null) {
                byte[] buf = IOUtils.toByteArray(rw.getInputStream());
                //byte[] buf = rw.getInputStream();
                if (buf.length > 0) {
                    String payloadSlimmed;
                    try {
                        String payload = new String(buf, 0, buf.length, rw.getCharacterEncoding());
                        payloadSlimmed = payload.trim().replaceAll(" +", " ");
                    } catch (UnsupportedEncodingException ex) {
                        payloadSlimmed = "[unknown]";
                    }

                    trace.put("body", payloadSlimmed);
                }
            }
        } catch (IOException ioex) {
            trace.put("body", "EXCEPTION: " + ioex.getMessage());
        }
    }

    private void logTrace(HttpServletRequest request, Map<String, Object> trace) {
        Object method = trace.get("method");
        Object path = trace.get("path");
        Object statusCode = trace.get("statusCode");

        logger.info(String.format("%s %s produced an status code '%s'. Trace: '%s'", method, path, statusCode,
                trace));
    }

    protected Map<String, Object> getTrace(HttpServletRequest request, int status) {
        Throwable exception = (Throwable) request.getAttribute("javax.servlet.error.exception");

        Principal principal = request.getUserPrincipal();

        Map<String, Object> trace = new LinkedHashMap<String, Object>();
        trace.put("method", request.getMethod());
        trace.put("path", request.getRequestURI());
        if (null != principal) {
            trace.put("principal", principal.getName());
        }
        trace.put("query", request.getQueryString());
        trace.put("statusCode", status);

        Enumeration headerNames = request.getHeaderNames();
        while (headerNames.hasMoreElements()) {
            String key = (String) headerNames.nextElement();
            String value = request.getHeader(key);
            trace.put("header:" + key, value);
        }

        if (exception != null && this.errorAttributes != null) {
            trace.put("error", this.errorAttributes
                    .getErrorAttributes((WebRequest) new ServletRequestAttributes(request), true));
        }

        return trace;
    }
}

请将此代码与一粒盐一起使用。

最重要的“测试”是POST是否适用于有效负载。这就是暴露“双重读取”问题的原因。

伪示例代码

import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("myroute")
public class MyController {
    @RequestMapping(method = RequestMethod.POST, produces = "application/json")
    @ResponseBody
    public String getSomethingExample(@RequestBody MyCustomObject input) {

        String returnValue = "";

        return returnValue;
    }
}

如果只想测试，可以用普通的“对象”替换“ MyCustomObject”。

这个答案来自一些不同的SOF帖子和示例。.但是花了一些时间才把它们放在一起，所以我希望它对将来的读者有所帮助。

请在我之前反对Lathy的回答。没有它，我不可能走那么远。

下面是我在解决此问题时遇到的一些异常。

getReader（）已为此请求被调用

看起来像我“借来”的一些地方在这里：

http://slackspace.de/articles/log-request-body-with-spring-boot/

https://github.com/c0nscience/spring-web-logging/blob/master/src/main/java/org/zalando/springframework/web/logging/LoggingFilter.java

https://howtodoinjava.com/servlets/httpservletrequestwrapper-example-read-request-body/

https://www.oodlestechnologies.com/blogs/How-to-create-duplicate-object-of-httpServletRequest-object

https://github.com/c0nscience/spring-web-logging/blob/master/src/main/java/org/zalando/springframework/web/logging/LoggingFilter.java

Answer 8

Spring通过navigation对此提供了内置支持：

dequeue_options.navigation := DBMS_AQ.FIRST_MESSAGE;

不幸的是，您仍然无法直接从请求中读取有效负载，但是String消息参数将包含有效负载，因此您可以从此处抓取它，如下所示：

AbstractRequestLoggingFilter

Answer 9

查看（或使用）Spring AbstractRequestLoggingFilter

Answer 10

如果您可以控制请求，则可以将内容类型设置为 binary / octet-stream 。这允许在不消耗输入流的情况下查询参数。

但是，这可能是特定于某些应用程序服务器的。我只测试了tomcat，根据https://stackoverflow.com/a/11434646/957103，jetty的行为似乎相同。

Answer 11

Spring类ContentCachingRequestWrapper的getContentAsByteArray（）方法多次读取主体，但是同一类的getInputStream（）和getReader（）方法不会多次读取主体：

“此类通过使用InputStream来缓存请求正文。如果我们在其中一个过滤器中读取InputStream，则过滤器链中的其他后续过滤器将无法再读取它。由于此限制，此类无法适合所有情况。”

对于我来说，解决此问题的更通用的解决方案是在我的Spring引导项目中添加以下三个类（以及对pom文件的必需依赖项）：

CachedBodyHttpServletRequest.java：

public class CachedBodyHttpServletRequest extends HttpServletRequestWrapper {

    private byte[] cachedBody;

    public CachedBodyHttpServletRequest(HttpServletRequest request) throws IOException {
        super(request);
        InputStream requestInputStream = request.getInputStream();
        this.cachedBody = StreamUtils.copyToByteArray(requestInputStream);
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        return new CachedBodyServletInputStream(this.cachedBody);
    }

    @Override
    public BufferedReader getReader() throws IOException {
        // Create a reader from cachedContent
        // and return it
        ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(this.cachedBody);
        return new BufferedReader(new InputStreamReader(byteArrayInputStream));
    }
}

CachedBodyServletInputStream.java：

public class CachedBodyServletInputStream extends ServletInputStream {

    private InputStream cachedBodyInputStream;

    public CachedBodyServletInputStream(byte[] cachedBody) {
        this.cachedBodyInputStream = new ByteArrayInputStream(cachedBody);
    }

    @Override
    public boolean isFinished() {
        try {
            return cachedBodyInputStream.available() == 0;
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return false;
    }

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

    @Override
    public void setReadListener(ReadListener readListener) {
        throw new UnsupportedOperationException();
    }

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

ContentCachingFilter.java：

@Order(value = Ordered.HIGHEST_PRECEDENCE)
@Component
@WebFilter(filterName = "ContentCachingFilter", urlPatterns = "/*")
public class ContentCachingFilter extends OncePerRequestFilter {

    @Override
    protected void doFilterInternal(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, FilterChain filterChain) throws ServletException, IOException {
        System.out.println("IN  ContentCachingFilter ");
        CachedBodyHttpServletRequest cachedBodyHttpServletRequest = new CachedBodyHttpServletRequest(httpServletRequest);
        filterChain.doFilter(cachedBodyHttpServletRequest, httpServletResponse);
    }
}

我还向pom添加了以下依赖项：

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.2.0.RELEASE</version>
</dependency>
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>4.0.1</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.10.0</version>
</dependency>

此处提供了完整的源代码： https://www.baeldung.com/spring-reading-httpservletrequest-multiple-times

Answer 12

我发现任何格式的请求正文都是很好的解决方案。我测试了application/x-www-form-urlencoded和application/json都工作得很好。仅针对ContentCachingRequestWrapper请求正文设计的x-www-form-urlencoded问题，不适用于例如json。我找到了json link的解决方案。不支持x-www-form-urlencoded的问题。我将两者都加入了我的代码：

import org.apache.commons.io.IOUtils;
import org.springframework.web.util.ContentCachingRequestWrapper;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;

public class MyContentCachingRequestWrapper extends ContentCachingRequestWrapper {

    private byte[] body;

    public MyContentCachingRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        super.getParameterMap(); // init cache in ContentCachingRequestWrapper
        body = super.getContentAsByteArray(); // first option for application/x-www-form-urlencoded
        if (body.length == 0) {
            body = IOUtils.toByteArray(super.getInputStream()); // second option for other body formats
        }
    }

    public byte[] getBody() {
        return body;
    }

    @Override
    public ServletInputStream getInputStream() {
        return new RequestCachingInputStream(body);
    }

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

    private static class RequestCachingInputStream extends ServletInputStream {

        private final ByteArrayInputStream inputStream;

        public RequestCachingInputStream(byte[] bytes) {
            inputStream = new ByteArrayInputStream(bytes);
        }

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

        @Override
        public boolean isFinished() {
            return inputStream.available() == 0;
        }

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

        @Override
        public void setReadListener(ReadListener readlistener) {
        }

    }

}

Answer 13

你可以使用servlet过滤器链，但是使用原来的，你可以创建自己的请求你的请求扩展HttpServletRequestWrapper。

Answer 14

首先，我们不应该读取过滤器中的参数。通常在过滤器中读取标头以执行一些身份验证任务。说过可以使用CharStreams在Filter或Interceptor中完全读取HttpRequest主体：

String body = com.google.common.io.CharStreams.toString(request.getReader());

这根本不会影响后续的读取。

读取一次后，Http Servlet请求从POST主体丢失params

14 个答案: