Class HttpResponse.BodyHandlers
- java.lang.Object
-
- java.net.http.HttpResponse.BodyHandlers
- Enclosing interface:
- HttpResponse<T>
public static class HttpResponse.BodyHandlers extends Object
Implementations of BodyHandler
that implement various useful handlers, such as handling the response body as a String, or streaming the response body to a file.
These implementations do not examine the status code, meaning the body is always accepted. They typically return an equivalently named BodySubscriber
. Alternatively, a custom handler can be used to examine the status code and headers, and return a different body subscriber, of the same type, as appropriate.
The following are examples of using the predefined body handlers to convert a flow of response body data into common high-level Java objects:
// Receives the response body as a String HttpResponse<String> response = client .send(request, BodyHandlers.ofString()); // Receives the response body as a file HttpResponse<Path> response = client .send(request, BodyHandlers.ofFile(Paths.get("example.html"))); // Receives the response body as an InputStream HttpResponse<InputStream> response = client .send(request, BodyHandlers.ofInputStream()); // Discards the response body HttpResponse<Void> response = client .send(request, BodyHandlers.discarding());
- Since:
- 11
Method Summary
Modifier and Type | Method | Description |
---|---|---|
static <T> HttpResponse.BodyHandler<T> | buffering(HttpResponse.BodyHandler<T> downstreamHandler,
int bufferSize) | Returns a |
static HttpResponse.BodyHandler<Void> | discarding() | Returns a response body handler that discards the response body. |
static HttpResponse.BodyHandler<Void> | fromLineSubscriber(Flow.Subscriber<? super String> subscriber) | Returns a response body handler that returns a |
static <S extends Flow.Subscriber<? super String>,T> | fromLineSubscriber(S subscriber,
Function<? super S,? extends T> finisher,
String lineSeparator) | Returns a response body handler that returns a |
static HttpResponse.BodyHandler<Void> | fromSubscriber(Flow.Subscriber<? super List<ByteBuffer>> subscriber) | Returns a response body handler that returns a |
static <S extends Flow.Subscriber<? super List<ByteBuffer>>,T> | fromSubscriber(S subscriber,
Function<? super S,? extends T> finisher) | Returns a response body handler that returns a |
static HttpResponse.BodyHandler<byte[]> | ofByteArray() | Returns a |
static HttpResponse.BodyHandler<Void> | ofByteArrayConsumer(Consumer<Optional<byte[]>> consumer) | Returns a |
static HttpResponse.BodyHandler<Path> | ofFile(Path file) | Returns a |
static HttpResponse.BodyHandler<Path> | ofFile(Path file,
OpenOption... openOptions) | Returns a |
static HttpResponse.BodyHandler<Path> | ofFileDownload(Path directory,
OpenOption... openOptions) | Returns a |
static HttpResponse.BodyHandler<InputStream> | ofInputStream() | Returns a |
static HttpResponse.BodyHandler<Stream<String>> | ofLines() | Returns a |
static HttpResponse.BodyHandler<Flow.Publisher<List<ByteBuffer>>> | ofPublisher() | Returns a |
static HttpResponse.BodyHandler<String> | ofString() | Returns a |
static HttpResponse.BodyHandler<String> | ofString(Charset charset) | Returns a |
static <U> HttpResponse.BodyHandler<U> | replacing(U value) | Returns a response body handler that returns the given replacement value, after discarding 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.BodyHandler<Void> fromSubscriber(Flow.Subscriber<? super List<ByteBuffer>> subscriber)
Returns a response body handler that returns a BodySubscriber
<Void>
obtained from HttpResponse.BodySubscribers.fromSubscriber(Subscriber)
, with the given subscriber
.
The response body is not available through this, or the
HttpResponse
API, but instead all response body is forwarded to the given subscriber
, which should make it available, if appropriate, through some other mechanism, e.g. an entry in a database, etc.
- API Note:
- This method can be used as an adapter between
BodySubscriber
andFlow.Subscriber
.For example:
TextSubscriber subscriber = new TextSubscriber(); HttpResponse<Void> response = client.sendAsync(request, BodyHandlers.fromSubscriber(subscriber)).join(); System.out.println(response.statusCode());
- Parameters:
-
subscriber
- the subscriber - Returns:
- a response body handler
fromSubscriber
public static <S extends Flow.Subscriber<? super List<ByteBuffer>>,T> HttpResponse.BodyHandler<T> fromSubscriber(S subscriber, Function<? super S,? extends T> finisher)
Returns a response body handler that returns a BodySubscriber
<T>
obtained from HttpResponse.BodySubscribers.fromSubscriber(Subscriber, Function)
, with the given subscriber
and finisher
function.
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
.For example:
TextSubscriber subscriber = ...; // accumulates bytes and transforms them into a String HttpResponse<String> response = client.sendAsync(request, BodyHandlers.fromSubscriber(subscriber, TextSubscriber::getTextResult)).join(); String text = response.body();
- 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 response body handler
fromLineSubscriber
public static HttpResponse.BodyHandler<Void> fromLineSubscriber(Flow.Subscriber<? super String> subscriber)
Returns a response body handler that returns a BodySubscriber
<Void>
obtained from BodySubscribers.fromLineSubscriber(subscriber, s -> null, charset, null)
, with the given subscriber
. The charset
used to decode the response body bytes is obtained from the HTTP response headers as specified by ofString()
, and lines are delimited in the manner of BufferedReader.readLine()
.
The response body is not available through this, or the
HttpResponse
API, but instead all response body is forwarded to the given subscriber
, which should make it available, if appropriate, through some other mechanism, e.g. an entry in a database, etc.
- API Note:
- This method can be used as an adapter between a
BodySubscriber
and a text basedFlow.Subscriber
that parses text line by line.For example:
// A PrintSubscriber that implements Flow.Subscriber<String> // and print lines received by onNext() on System.out PrintSubscriber subscriber = new PrintSubscriber(System.out); client.sendAsync(request, BodyHandlers.fromLineSubscriber(subscriber)) .thenApply(HttpResponse::statusCode) .thenAccept((status) -> { if (status != 200) { System.err.printf("ERROR: %d status received%n", status); } });
- Parameters:
-
subscriber
- the subscriber - Returns:
- a response body handler
fromLineSubscriber
public static <S extends Flow.Subscriber<? super String>,T> HttpResponse.BodyHandler<T> fromLineSubscriber(S subscriber, Function<? super S,? extends T> finisher, String lineSeparator)
Returns a response body handler that returns a BodySubscriber
<T>
obtained from BodySubscribers.fromLineSubscriber(subscriber, finisher, charset, lineSeparator)
, with the given subscriber
, finisher
function, and line separator. The charset
used to decode the response body bytes is obtained from the HTTP response headers as specified by ofString()
.
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 a
BodySubscriber
and a text basedFlow.Subscriber
that parses text line by line.For example:
// A LineParserSubscriber that implements Flow.Subscriber<String> // and accumulates lines that match a particular pattern Pattern pattern = ...; LineParserSubscriber subscriber = new LineParserSubscriber(pattern); HttpResponse<List<String>> response = client.send(request, BodyHandlers.fromLineSubscriber(subscriber, s -> s.getMatchingLines(), "\n")); if (response.statusCode() != 200) { System.err.printf("ERROR: %d status received%n", response.statusCode()); }
- 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 -
lineSeparator
- an optional line separator: can benull
, in which case lines will be delimited in the manner ofBufferedReader.readLine()
. - Returns:
- a response body handler
- Throws:
-
IllegalArgumentException
- if the suppliedlineSeparator
is the empty string
discarding
public static HttpResponse.BodyHandler<Void> discarding()
Returns a response body handler that discards the response body.
- Returns:
- a response body handler
replacing
public static <U> HttpResponse.BodyHandler<U> replacing(U value)
Returns a response body handler that returns the given replacement value, after discarding the response body.
- Type Parameters:
-
U
- the response body type - Parameters:
-
value
- the value of U to return as the body, may benull
- Returns:
- a response body handler
ofString
public static HttpResponse.BodyHandler<String> ofString(Charset charset)
Returns a BodyHandler<String>
that returns a BodySubscriber
<String>
obtained from BodySubscribers.ofString(Charset)
. The body is decoded using the given character set.
- Parameters:
-
charset
- the character set to convert the body with - Returns:
- a response body handler
ofFile
public static HttpResponse.BodyHandler<Path> ofFile(Path file, OpenOption... openOptions)
Returns a BodyHandler<Path>
that returns a BodySubscriber
<Path>
obtained from BodySubscribers.ofFile(Path,OpenOption...)
.
When the HttpResponse
object is returned, the body has been completely written to the file, and HttpResponse.body()
returns a reference to its Path
.
Security manager permission checks are performed in this factory method, when the BodyHandler
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
- any options to use when opening/creating the file - Returns:
- a response body handler
- 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.BodyHandler<Path> ofFile(Path file)
Returns a BodyHandler<Path>
that returns a BodySubscriber
<Path>
.
Equivalent to: ofFile(file, CREATE, WRITE)
Security manager permission checks are performed in this factory method, when the BodyHandler
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 response body handler
- Throws:
-
SecurityException
- If a security manager has been installed and it denieswrite access
to the file.
ofFileDownload
public static HttpResponse.BodyHandler<Path> ofFileDownload(Path directory, OpenOption... openOptions)
Returns a BodyHandler<Path>
that returns a BodySubscriber
<Path
> where the download directory is specified, but the filename is obtained from the Content-Disposition
response header. The Content-Disposition
header must specify the attachment type and must also contain a filename parameter. If the filename specifies multiple path components only the final component is used as the filename (with the given directory name).
When the HttpResponse
object is returned, the body has been completely written to the file and HttpResponse.body()
returns a Path
object for the file. The returned Path
is the combination of the supplied directory name and the file name supplied by the server. If the destination directory does not exist or cannot be written to, then the response will fail with an IOException
.
Security manager permission checks are performed in this factory method, when the BodyHandler
is created. Care must be taken that the BodyHandler
is not shared with untrusted code.
- Parameters:
-
directory
- the directory to store the file in -
openOptions
- open options used when opening the file - Returns:
- a response body handler
- Throws:
-
IllegalArgumentException
- if the given path does not exist, is not a directory, is not writable, or if an invalid set of open options are specified -
SecurityException
- If a security manager has been installed and it denies read access to the directory, or it denies write access to the directory, or it denies write access to the files within the directory.
ofInputStream
public static HttpResponse.BodyHandler<InputStream> ofInputStream()
Returns a BodyHandler<InputStream>
that returns a BodySubscriber
<InputStream>
obtained from BodySubscribers.ofInputStream
.
When the HttpResponse
object is returned, the response headers will have been completely read, but the body may not have been fully received yet. The HttpResponse.body()
method returns an InputStream
from which the body can be read as it is received.
- API Note:
- See
HttpResponse.BodySubscribers.ofInputStream()
for more information. - Returns:
- a response body handler
ofLines
public static HttpResponse.BodyHandler<Stream<String>> ofLines()
Returns a BodyHandler<Stream<String>>
that returns a BodySubscriber
<Stream<String>>
obtained from BodySubscribers.ofLines(charset)
. The charset
used to decode the response body bytes is obtained from the HTTP response headers as specified by ofString()
, and lines are delimited in the manner of BufferedReader.readLine()
.
When the HttpResponse
object is returned, the body may not have been completely received.
- Returns:
- a response body handler
ofByteArrayConsumer
public static HttpResponse.BodyHandler<Void> ofByteArrayConsumer(Consumer<Optional<byte[]>> consumer)
Returns a BodyHandler<Void>
that returns a BodySubscriber
<Void>
obtained from BodySubscribers.ofByteArrayConsumer(Consumer)
.
When the HttpResponse
object is returned, the body has been completely written to the consumer.
- API Note:
- The subscriber returned by this handler 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 to accept the response body - Returns:
- a response body handler
ofByteArray
public static HttpResponse.BodyHandler<byte[]> ofByteArray()
Returns a BodyHandler<byte[]>
that returns a BodySubscriber
<byte[]
> obtained from BodySubscribers.ofByteArray()
.
When the HttpResponse
object is returned, the body has been completely written to the byte array.
- Returns:
- a response body handler
ofString
public static HttpResponse.BodyHandler<String> ofString()
Returns a BodyHandler<String>
that returns a BodySubscriber
<String>
obtained from BodySubscribers.ofString(Charset)
. The body is decoded using the character set specified in the Content-Type
response header. If there is no such header, or the character set is not supported, then UTF_8
is used.
When the HttpResponse
object is returned, the body has been completely written to the string.
- Returns:
- a response body handler
ofPublisher
public static HttpResponse.BodyHandler<Flow.Publisher<List<ByteBuffer>>> ofPublisher()
Returns a BodyHandler<Publisher<List<ByteBuffer>>>
that creates a BodySubscriber
<Publisher<List<ByteBuffer>>>
obtained from BodySubscribers.ofPublisher()
.
When the HttpResponse
object is returned, the response headers will have been completely read, but the body may not have been fully received yet. The HttpResponse.body()
method returns a Publisher
from which the body response bytes can be obtained as they are received. The publisher can and must be subscribed to only once.>
- API Note:
- See
HttpResponse.BodySubscribers.ofPublisher()
for more information. - Returns:
- a response body handler
buffering
public static <T> HttpResponse.BodyHandler<T> buffering(HttpResponse.BodyHandler<T> downstreamHandler, int bufferSize)
Returns a BodyHandler
which, when invoked, returns a buffering BodySubscriber that buffers data before delivering it to the downstream subscriber. These BodySubscriber
instances are created by calling BodySubscribers.buffering
with a subscriber obtained from the given downstream handler and the bufferSize
parameter.
- Type Parameters:
-
T
- the response body type - Parameters:
-
downstreamHandler
- the downstream handler -
bufferSize
- the buffer size parameter passed toBodySubscribers.buffering
- Returns:
- a body handler
- Throws:
-
IllegalArgumentException
- ifbufferSize <= 0