- All Implemented Interfaces:
Request,AutoCloseable
- Direct Known Subclasses:
HttpsExchange
The typical life-cycle of a HttpExchange is shown in the sequence
below:
getRequestMethod()to determine the command.getRequestHeaders()to examine the request headers (if needed).getRequestBody()returns anInputStreamfor reading the request body. After reading the request body, the stream should be closed.getResponseHeaders()to set any response headers, except content-length.sendResponseHeaders(int,long)to send the response headers. Must be called before next step.getResponseBody()to get aOutputStreamto send the response body. When the response body has been written, the stream must be closed to terminate the exchange.
Exchanges are terminated when both the request
InputStream and
response OutputStream are closed. Closing the OutputStream,
implicitly closes the InputStream (if it is not already closed).
However, it is recommended to consume all the data from the InputStream
before closing it. The convenience method close() does all of these
tasks. Closing an exchange without consuming all of the request body is not
an error but may make the underlying TCP connection unusable for following
exchanges. The effect of failing to terminate an exchange is undefined, but
will typically result in resources failing to be freed/reused.- Since:
- 1.6
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionabstract voidclose()Ends this exchange by doing the following in sequence: close the requestInputStream, if not already closed.abstract ObjectgetAttribute(String name) Filtermodules may store arbitrary objects withHttpExchangeinstances as an out-of-band communication mechanism.abstract HttpContextReturns theHttpContextfor this exchange.abstract InetSocketAddressReturns the local address on which the request was received.abstract HttpPrincipalIf an authenticator is set on theHttpContextthat owns this exchange, then this method will return theHttpPrincipalthat represents the authenticated user for thisHttpExchange.abstract StringReturns the protocol string from the request in the form protocol/majorVersion.minorVersion.abstract InetSocketAddressReturns the address of the remote entity invoking this request.abstract InputStreamReturns a stream from which the request body can be read.abstract HeadersReturns an immutableHeaderscontaining the HTTP headers that were included with this request.abstract StringReturns the request method.abstract URIReturns the requestURI.abstract OutputStreamReturns a stream to which the response body must be written.abstract intReturns the response code, if it has already been set.abstract HeadersReturns a mutableHeadersinto which the HTTP response headers can be stored and which will be transmitted as part of this response.abstract voidsendResponseHeaders(int rCode, long responseLength) Starts sending the response back to the client using the current set of response headers and the numeric response code as specified in this method.abstract voidsetAttribute(String name, Object value) Filtermodules may store arbitrary objects withHttpExchangeinstances as an out-of-band communication mechanism.abstract voidUsed by Filters to wrap either (or both) of this exchange'sInputStreamandOutputStream, with the given filtered streams so that subsequent calls togetRequestBody()will return the givenInputStream, and calls togetResponseBody()will return the givenOutputStream.
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Constructor Details
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HttpExchange
protected HttpExchange()Constructor for subclasses to call.
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Method Details
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getRequestHeaders
Returns an immutableHeaderscontaining the HTTP headers that were included with this request.The keys in this
Headersare the header names, while the values are aListof Strings containing each value that was included in the request, in the order they were included. Header fields appearing multiple times are represented as multiple string values.The keys in
Headersare case-insensitive.- Specified by:
getRequestHeadersin interfaceRequest- Returns:
- a read-only
Headerswhich can be used to access request headers.
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getResponseHeaders
Returns a mutableHeadersinto which the HTTP response headers can be stored and which will be transmitted as part of this response.The keys in the
Headersare the header names, while the values must be aListof Strings containing each value that should be included multiple times (in the order that they should be included).The keys in
Headersare case-insensitive.- Returns:
- a writable
Headerswhich can be used to set response headers.
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getRequestURI
Returns the requestURI.- Specified by:
getRequestURIin interfaceRequest- Returns:
- the request
URI
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getRequestMethod
Returns the request method.- Specified by:
getRequestMethodin interfaceRequest- Returns:
- the request method string
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getHttpContext
Returns theHttpContextfor this exchange.- Returns:
- the
HttpContext
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close
public abstract void close()Ends this exchange by doing the following in sequence:- close the request
InputStream, if not already closed. - close the response
OutputStream, if not already closed.
- Specified by:
closein interfaceAutoCloseable
- close the request
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getRequestBody
Returns a stream from which the request body can be read. Multiple calls to this method will return the same stream. It is recommended that applications should consume (read) all of the data from this stream before closing it. If a stream is closed before all data has been read, then theInputStream.close()call will read and discard remaining data (up to an implementation specific number of bytes).- Returns:
- the stream from which the request body can be read
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getResponseBody
Returns a stream to which the response body must be written.sendResponseHeaders(int,long)) must be called prior to calling this method. Multiple calls to this method (for the same exchange) will return the same stream. In order to correctly terminate each exchange, the output stream must be closed, even if no response body is being sent.Closing this stream implicitly closes the
InputStreamreturned fromgetRequestBody()(if it is not already closed).If the call to
sendResponseHeaders(int, long)specified a fixed response body length, then the exact number of bytes specified in that call must be written to this stream. If too many bytes are written, then the write method ofOutputStreamwill throw anIOException. If too few bytes are written then the streamOutputStream.close()will throw anIOException. In both cases, the exchange is aborted and the underlying TCP connection closed.- Returns:
- the stream to which the response body is written
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sendResponseHeaders
Starts sending the response back to the client using the current set of response headers and the numeric response code as specified in this method. The response body length is also specified as follows. If the response length parameter is greater thanzero, this specifies an exact number of bytes to send and the application must send that exact amount of data. If the response length parameter iszero, then chunked transfer encoding is used and an arbitrary amount of data may be sent. The application terminates the response body by closing theOutputStream. If response length has the value-1then no response body is being sent.If the content-length response header has not already been set then this is set to the appropriate value depending on the response length parameter.
This method must be called prior to calling
getResponseBody().- Implementation Note:
- This implementation allows the caller to instruct the
server to force a connection close after the exchange terminates, by
supplying a
Connection: closeheader to the response headers beforesendResponseHeadersis called. - Parameters:
rCode- the response code to sendresponseLength- if > 0, specifies a fixed response body length and that exact number of bytes must be written to the stream acquired fromgetResponseCode()If == 0, then chunked encoding is used, and an arbitrary number of bytes may be written. If <= -1, then no response body length is specified and no response body may be written.- Throws:
IOException- if the response headers have already been sent or an I/O error occurs- See Also:
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getRemoteAddress
Returns the address of the remote entity invoking this request.- Returns:
- the
InetSocketAddressof the caller
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getResponseCode
public abstract int getResponseCode()Returns the response code, if it has already been set.- Returns:
- the response code, if available.
-1if not available yet.
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getLocalAddress
Returns the local address on which the request was received.- Returns:
- the
InetSocketAddressof the local interface
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getProtocol
Returns the protocol string from the request in the form protocol/majorVersion.minorVersion. For example, "HTTP/1.1".- Returns:
- the protocol string from the request
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getAttribute
Filtermodules may store arbitrary objects withHttpExchangeinstances as an out-of-band communication mechanism. Other filters or the exchange handler may then access these objects.Each
Filterclass will document the attributes which they make available.- Parameters:
name- the name of the attribute to retrieve- Returns:
- the attribute object, or
nullif it does not exist - Throws:
NullPointerException- if name isnull
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setAttribute
Filtermodules may store arbitrary objects withHttpExchangeinstances as an out-of-band communication mechanism. Other filters or the exchange handler may then access these objects.Each
Filterclass will document the attributes which they make available.- Parameters:
name- the name to associate with the attribute valuevalue- the object to store as the attribute value.nullvalue is permitted.- Throws:
NullPointerException- if name isnull
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setStreams
Used by Filters to wrap either (or both) of this exchange'sInputStreamandOutputStream, with the given filtered streams so that subsequent calls togetRequestBody()will return the givenInputStream, and calls togetResponseBody()will return the givenOutputStream. The streams provided to this call must wrap the original streams, and may be (but are not required to be) sub-classes ofFilterInputStreamandFilterOutputStream.- Parameters:
i- the filtered input stream to set as this object'sInputstream, ornullif no changeo- the filtered output stream to set as this object'sOutputstream, ornullif no change
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getPrincipal
If an authenticator is set on theHttpContextthat owns this exchange, then this method will return theHttpPrincipalthat represents the authenticated user for thisHttpExchange.- Returns:
- the
HttpPrincipal, ornullif no authenticator is set
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