Class HttpResponse.BodySubscribers
- java.lang.Object
-
- java.net.http.HttpResponse.BodySubscribers
- Enclosing interface:
- HttpResponse<T>
public static class HttpResponse.BodySubscribers extends Object
Implementations of BodySubscriber
that implement various useful subscribers, such as converting the response body bytes into a String, or streaming the bytes to a file.
The following are examples of using the predefined body subscribers to convert a flow of response body data into common high-level Java objects:
// Streams the response body to a File HttpResponse<byte[]> response = client .send(request, responseInfo -> BodySubscribers.ofByteArray()); // Accumulates the response body and returns it as a byte[] HttpResponse<byte[]> response = client .send(request, responseInfo -> BodySubscribers.ofByteArray()); // Discards the response body HttpResponse<Void> response = client .send(request, responseInfo -> BodySubscribers.discarding()); // Accumulates the response body as a String then maps it to its bytes HttpResponse<byte[]> response = client .send(request, responseInfo -> BodySubscribers.mapping(BodySubscribers.ofString(UTF_8), String::getBytes));
- Since:
- 11
Method Summary
Modifier and Type | Method | Description |
---|---|---|
static <T> HttpResponse.BodySubscriber<T> | buffering(HttpResponse.BodySubscriber<T> downstream,
int bufferSize) | Returns a |
static HttpResponse.BodySubscriber<Void> | discarding() | Returns a response subscriber which discards the response body. |
static HttpResponse.BodySubscriber<Void> | fromLineSubscriber(Flow.Subscriber<? super String> subscriber) | Returns a body subscriber that forwards all response body to the given |
static <S extends Flow.Subscriber<? super String>,T> | fromLineSubscriber(S subscriber,
Function<? super S,? extends T> finisher,
Charset charset,
String lineSeparator) | Returns a body subscriber that forwards all response body to the given |
static HttpResponse.BodySubscriber<Void> | fromSubscriber(Flow.Subscriber<? super List<ByteBuffer>> subscriber) | Returns a body subscriber that forwards all response body to the given |
static <S extends Flow.Subscriber<? super List<ByteBuffer>>,T> | fromSubscriber(S subscriber,
Function<? super S,? extends T> finisher) | Returns a body subscriber that forwards all response body to the given |
static <T,U> | mapping(HttpResponse.BodySubscriber<T> upstream,
Function<? super T,? extends U> mapper) | Returns a |
static HttpResponse.BodySubscriber<byte[]> | ofByteArray() | Returns a |
static HttpResponse.BodySubscriber<Void> | ofByteArrayConsumer(Consumer<Optional<byte[]>> consumer) | Returns a |
static HttpResponse.BodySubscriber<Path> | ofFile(Path file) | Returns a |
static HttpResponse.BodySubscriber<Path> | ofFile(Path file,
OpenOption... openOptions) | Returns a |
static HttpResponse.BodySubscriber<InputStream> | ofInputStream() | Returns a |
static HttpResponse.BodySubscriber<Stream<String>> | ofLines(Charset charset) | Returns a |
static HttpResponse.BodySubscriber<Flow.Publisher<List<ByteBuffer>>> | ofPublisher() | Returns a response subscriber which publishes the response body through a |
static HttpResponse.BodySubscriber<String> | ofString(Charset charset) | Returns a body subscriber which stores the response body as a |
static <U> HttpResponse.BodySubscriber<U> | replacing(U value) | Returns a response subscriber which discards the response body. |
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Method Detail
fromSubscriber
public static HttpResponse.BodySubscriber<Void> fromSubscriber(Flow.Subscriber<? super List<ByteBuffer>> subscriber)
Returns a body subscriber that forwards all response body to the given Flow.Subscriber
. The completion stage of the returned body subscriber completes after one of the given subscribers onComplete
or onError
has been invoked.
- API Note:
- This method can be used as an adapter between
BodySubscriber
andFlow.Subscriber
. - Parameters:
-
subscriber
- the subscriber - Returns:
- a body subscriber
fromSubscriber
public static <S extends Flow.Subscriber<? super List<ByteBuffer>>,T> HttpResponse.BodySubscriber<T> fromSubscriber(S subscriber, Function<? super S,? extends T> finisher)
Returns a body subscriber that forwards all response body to the given Flow.Subscriber
. The completion stage of the returned body subscriber completes after one of the given subscribers onComplete
or onError
has been invoked.
The given finisher
function is applied after the given subscriber's onComplete
has been invoked. The finisher
function is invoked with the given subscriber, and returns a value that is set as the response's body.
- API Note:
- This method can be used as an adapter between
BodySubscriber
andFlow.Subscriber
. - Type Parameters:
-
S
- the type of the Subscriber -
T
- the type of the response body - Parameters:
-
subscriber
- the subscriber -
finisher
- a function to be applied after the subscriber has completed - Returns:
- a body subscriber
fromLineSubscriber
public static HttpResponse.BodySubscriber<Void> fromLineSubscriber(Flow.Subscriber<? super String> subscriber)
Returns a body subscriber that forwards all response body to the given Flow.Subscriber
, line by line. The completion stage of the returned body subscriber completes after one of the given subscribers onComplete
or onError
has been invoked. Bytes are decoded using the UTF-8
charset, and lines are delimited in the manner of BufferedReader.readLine()
.
- API Note:
- This method can be used as an adapter between
BodySubscriber
andFlow.Subscriber
. - Implementation Note:
- This is equivalent to calling
fromLineSubscriber(subscriber, s -> null, StandardCharsets.UTF_8, null)
- Parameters:
-
subscriber
- the subscriber - Returns:
- a body subscriber
fromLineSubscriber
public static <S extends Flow.Subscriber<? super String>,T> HttpResponse.BodySubscriber<T> fromLineSubscriber(S subscriber, Function<? super S,? extends T> finisher, Charset charset, String lineSeparator)
Returns a body subscriber that forwards all response body to the given Flow.Subscriber
, line by line. The completion stage of the returned body subscriber completes after one of the given subscribers onComplete
or onError
has been invoked.
The given finisher
function is applied after the given subscriber's onComplete
has been invoked. The finisher
function is invoked with the given subscriber, and returns a value that is set as the response's body.
- API Note:
- This method can be used as an adapter between
BodySubscriber
andFlow.Subscriber
. - Type Parameters:
-
S
- the type of the Subscriber -
T
- the type of the response body - Parameters:
-
subscriber
- the subscriber -
finisher
- a function to be applied after the subscriber has completed -
charset
- aCharset
to decode the bytes -
lineSeparator
- an optional line separator: can benull
, in which case lines will be delimited in the manner ofBufferedReader.readLine()
. - Returns:
- a body subscriber
- Throws:
-
IllegalArgumentException
- if the suppliedlineSeparator
is the empty string
ofString
public static HttpResponse.BodySubscriber<String> ofString(Charset charset)
Returns a body subscriber which stores the response body as a
String
converted using the given Charset
.
The HttpResponse
using this subscriber is available after the entire response has been read.
- Parameters:
-
charset
- the character set to convert the String with - Returns:
- a body subscriber
ofByteArray
public static HttpResponse.BodySubscriber<byte[]> ofByteArray()
Returns a BodySubscriber
which stores the response body as a byte array.
The HttpResponse
using this subscriber is available after the entire response has been read.
- Returns:
- a body subscriber
ofFile
public static HttpResponse.BodySubscriber<Path> ofFile(Path file, OpenOption... openOptions)
Returns a BodySubscriber
which stores the response body in a file opened with the given options and name. The file will be opened with the given options using FileChannel.open
just before the body is read. Any exception thrown will be returned or thrown from HttpClient::send
or HttpClient::sendAsync
as appropriate.
The HttpResponse
using this subscriber is available after the entire response has been read.
Security manager permission checks are performed in this factory method, when the BodySubscriber
is created. Care must be taken that the BodyHandler
is not shared with untrusted code.
- Parameters:
-
file
- the file to store the body in -
openOptions
- the list of options to open the file with - Returns:
- a body subscriber
- Throws:
-
IllegalArgumentException
- if an invalid set of open options are specified -
SecurityException
- if a security manager has been installed and it denieswrite access
to the file
ofFile
public static HttpResponse.BodySubscriber<Path> ofFile(Path file)
Returns a BodySubscriber
which stores the response body in a file opened with the given name.
Equivalent to: ofFile(file, CREATE, WRITE)
Security manager permission checks are performed in this factory method, when the BodySubscriber
is created. Care must be taken that the BodyHandler
is not shared with untrusted code.
- Parameters:
-
file
- the file to store the body in - Returns:
- a body subscriber
- Throws:
-
SecurityException
- if a security manager has been installed and it denieswrite access
to the file
ofByteArrayConsumer
public static HttpResponse.BodySubscriber<Void> ofByteArrayConsumer(Consumer<Optional<byte[]>> consumer)
Returns a BodySubscriber
which provides the incoming body data to the provided Consumer of Optional<byte[]>
. Each call to Consumer.accept()
will contain a non empty Optional
, except for the final invocation after all body data has been read, when the
Optional
will be empty.
The HttpResponse
using this subscriber is available after the entire response has been read.
- API Note:
- This subscriber is not flow controlled. Therefore, the supplied consumer must be able to process whatever amount of data is delivered in a timely fashion.
- Parameters:
-
consumer
- a Consumer of byte arrays - Returns:
- a BodySubscriber
ofInputStream
public static HttpResponse.BodySubscriber<InputStream> ofInputStream()
Returns a BodySubscriber
which streams the response body as an InputStream
.
The HttpResponse
using this subscriber is available immediately after the response headers have been read, without requiring to wait for the entire body to be processed. The response body can then be read directly from the InputStream
.
- API Note:
- To ensure that all resources associated with the corresponding exchange are properly released the caller must ensure to either read all bytes until EOF is reached, or call
InputStream.close()
if it is unable or unwilling to do so. Callingclose
before exhausting the stream may cause the underlying HTTP connection to be closed and prevent it from being reused for subsequent operations. - Returns:
- a body subscriber that streams the response body as an
InputStream
.
ofLines
public static HttpResponse.BodySubscriber<Stream<String>> ofLines(Charset charset)
Returns a BodySubscriber
which streams the response body as a Stream
, where each string in the stream corresponds to a line as defined by BufferedReader.lines()
.
The HttpResponse
using this subscriber is available immediately after the response headers have been read, without requiring to wait for the entire body to be processed. The response body can then be read directly from the Stream
.
- API Note:
- To ensure that all resources associated with the corresponding exchange are properly released the caller must ensure to either read all lines until the stream is exhausted, or call
BaseStream.close()
if it is unable or unwilling to do so. Callingclose
before exhausting the stream may cause the underlying HTTP connection to be closed and prevent it from being reused for subsequent operations. - Parameters:
-
charset
- the character set to use when converting bytes to characters - Returns:
- a body subscriber that streams the response body as a
Stream
. - See Also:
BufferedReader.lines()
ofPublisher
public static HttpResponse.BodySubscriber<Flow.Publisher<List<ByteBuffer>>> ofPublisher()
Returns a response subscriber which publishes the response body through a Publisher<List<ByteBuffer>>
.
The HttpResponse
using this subscriber is available immediately after the response headers have been read, without requiring to wait for the entire body to be processed. The response body bytes can then be obtained by subscribing to the publisher returned by the HttpResponse
body
method.
The publisher returned by the body
method can be subscribed to only once. The first subscriber will receive the body response bytes if successfully subscribed, or will cause the subscription to be cancelled otherwise. If more subscriptions are attempted, the subsequent subscribers will be immediately subscribed with an empty subscription and their onError
method will be invoked with an IllegalStateException
.
- API Note:
- To ensure that all resources associated with the corresponding exchange are properly released the caller must ensure that the provided publisher is subscribed once, and either requests all bytes until
onComplete
oronError
are invoked, or cancel the provided subscription if it is unable or unwilling to do so. Note that depending on the actual HTTP protocol version used for the exchange, cancelling the subscription instead of exhausting the flow may cause the underlying HTTP connection to be closed and prevent it from being reused for subsequent operations. - Returns:
- A
BodySubscriber
which publishes the response body through aPublisher<List<ByteBuffer>>
.
replacing
public static <U> HttpResponse.BodySubscriber<U> replacing(U value)
Returns a response subscriber which discards the response body. The supplied value is the value that will be returned from HttpResponse.body()
.
- Type Parameters:
-
U
- the type of the response body - Parameters:
-
value
- the value to return from HttpResponse.body(), may benull
- Returns:
- a
BodySubscriber
discarding
public static HttpResponse.BodySubscriber<Void> discarding()
Returns a response subscriber which discards the response body.
- Returns:
- a response body subscriber
buffering
public static <T> HttpResponse.BodySubscriber<T> buffering(HttpResponse.BodySubscriber<T> downstream, int bufferSize)
Returns a BodySubscriber
which buffers data before delivering it to the given downstream subscriber. The subscriber guarantees to deliver buffersize
bytes of data to each invocation of the downstream's onNext
method, except for the final invocation, just before onComplete
is invoked. The final invocation of onNext
may contain fewer than bufferSize
bytes.
The returned subscriber delegates its getBody()
method to the downstream subscriber.
- Type Parameters:
-
T
- the type of the response body - Parameters:
-
downstream
- the downstream subscriber -
bufferSize
- the buffer size - Returns:
- a buffering body subscriber
- Throws:
-
IllegalArgumentException
- ifbufferSize <= 0
mapping
public static <T,U> HttpResponse.BodySubscriber<U> mapping(HttpResponse.BodySubscriber<T> upstream, Function<? super T,? extends U> mapper)
Returns a BodySubscriber
whose response body value is that of the result of applying the given function to the body object of the given upstream
BodySubscriber
.
The mapping function is executed using the client's executor, and can therefore be used to map any response body type, including blocking InputStream
, as shown in the following example which uses a well-known JSON parser to convert an InputStream
into any annotated Java type.
For example:
public static <W> BodySubscriber<W> asJSON(Class<W> targetType) { BodySubscriber<InputStream> upstream = BodySubscribers.ofInputStream(); BodySubscriber<W> downstream = BodySubscribers.mapping( upstream, (InputStream is) -> { try (InputStream stream = is) { ObjectMapper objectMapper = new ObjectMapper(); return objectMapper.readValue(stream, targetType); } catch (IOException e) { throw new UncheckedIOException(e); } }); return downstream; }
- Type Parameters:
-
T
- the upstream body type -
U
- the type of the body subscriber returned - Parameters:
-
upstream
- the body subscriber to be mapped -
mapper
- the mapping function - Returns:
- a mapping body subscriber