[英]Read JAX-RS body InputStream twice
我有一個JAX-RS日志記錄過濾器來記錄請求和響應的詳細信息,如下所示:
public class LoggingFilter implements ContainerRequestFilter, ContainerResponseFilter {
@Override
public void filter(final ContainerRequestContext requestContext) throws IOException {
...
String body = getBody(request);
...
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("request: {}", httpRequest);
}
}
}
getBody()
方法從InputStream
讀取正文內容,但是我需要做一些技巧,因為無法重置此流。 沒有這個小技巧,我的rest方法總是收到空的請求正文內容:
private String getBody(final ContainerRequestContext requestContext) {
try {
byte[] body = IOUtils.toByteArray(requestContext.getEntityStream());
InputStream stream = new ByteArrayInputStream(body);
requestContext.setEntityStream(stream);
return new String(body);
} catch (IOException e) {
return null;
}
}
有沒有更好的方法來讀取身體內容?
編輯這是一個改進的版本,看起來更加健壯,並使用JDK類。 只需在重用之前調用close()
。
public class CachingInputStream extends BufferedInputStream {
public CachingInputStream(InputStream source) {
super(new PostCloseProtection(source));
super.mark(Integer.MAX_VALUE);
}
@Override
public synchronized void close() throws IOException {
if (!((PostCloseProtection) in).decoratedClosed) {
in.close();
}
super.reset();
}
private static class PostCloseProtection extends InputStream {
private volatile boolean decoratedClosed = false;
private final InputStream source;
public PostCloseProtection(InputStream source) {
this.source = source;
}
@Override
public int read() throws IOException {
return decoratedClosed ? -1 : source.read();
}
@Override
public int read(byte[] b) throws IOException {
return decoratedClosed ? -1 : source.read(b);
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
return decoratedClosed ? -1 : source.read(b, off, len);
}
@Override
public long skip(long n) throws IOException {
return decoratedClosed ? 0 : source.skip(n);
}
@Override
public int available() throws IOException {
return source.available();
}
@Override
public void close() throws IOException {
decoratedClosed = true;
source.close();
}
@Override
public void mark(int readLimit) {
source.mark(readLimit);
}
@Override
public void reset() throws IOException {
source.reset();
}
@Override
public boolean markSupported() {
return source.markSupported();
}
}
}
通過將mark
調整為Integer.MAXVALUE
,可以讀取緩沖區中的整個流。 這還可以確保在第一次關閉時就正確關閉了源,以釋放OS資源。
舊答案
您可能不確定InputStream
支持標記( markSupported()
)的實際實現。 最好在第一個方法中緩存輸入流本身。
例如在ContainerRequestFilter
:
@Component
@Provider
@PreMatching
@Priority(1)
public class ReadSomethingInPayloadFilter implements ContainerRequestFilter {
@Override
public void filter(ContainerRequestContext request) throws IOException {
CachingInputStream entityStream = new CachingInputStream(request.getEntityStream());
readPayload(entityStream);
request.setEntityStream(entityStream.getCachedInputStream());
}
}
緩存輸入流是一種簡單的輸入流緩存方法,它與您的方法類似:
class CachingInputStream extends InputStream {
public static final int END_STREAM = -1;
private final InputStream is;
private final ByteArrayOutputStream baos = new ByteArrayOutputStream();
public CachingInputStream(InputStream is) {
this.is = is;
}
public InputStream getCachedInputStream() {
return new ByteArrayInputStream(baos.toByteArray());
}
@Override
public int read() throws IOException {
int result = is.read();
// Avoid rewriting the end char (-1) otherwise it will be considered as a real char.
if (result != END_STREAM)
baos.write(result);
return result;
}
@Override
public int available() throws IOException {
return is.available();
}
@Override
public void close() throws IOException {
is.close();
}
}
此實現在各種方面都很幼稚,可以在以下方面進行改進,甚至可能需要更多改進:
markSupported
在原始流上受支持
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