public interface ServletRequest
ServletRequest
object and passes
it as an argument to the servlet's service
method.
A ServletRequest
object provides data including
parameter name and values, attributes, and an input stream.
Interfaces that extend ServletRequest
can provide
additional protocol-specific data (for example, HTTP data is
provided by HttpServletRequest
.
HttpServletRequest
Modifier and Type | Method and Description |
---|---|
AsyncContext |
getAsyncContext()
Gets the AsyncContext that was created or reinitialized by the
most recent invocation of
startAsync() or
startAsync(ServletRequest,ServletResponse) on this request. |
Object |
getAttribute(String name)
Returns the value of the named attribute as an
Object ,
or null if no attribute of the given name exists. |
Enumeration<String> |
getAttributeNames()
Returns an
Enumeration containing the
names of the attributes available to this request. |
String |
getCharacterEncoding()
Returns the name of the character encoding used in the body of this
request.
|
int |
getContentLength()
Returns the length, in bytes, of the request body and made available by
the input stream, or -1 if the length is not known ir is greater than
Integer.MAX_VALUE.
|
long |
getContentLengthLong()
Returns the length, in bytes, of the request body and made available by
the input stream, or -1 if the length is not known.
|
String |
getContentType()
Returns the MIME type of the body of the request, or
null if the type is not known. |
DispatcherType |
getDispatcherType()
Gets the dispatcher type of this request.
|
ServletInputStream |
getInputStream()
Retrieves the body of the request as binary data using
a
ServletInputStream . |
String |
getLocalAddr()
Returns the Internet Protocol (IP) address of the interface on
which the request was received.
|
Locale |
getLocale()
Returns the preferred
Locale that the client will
accept content in, based on the Accept-Language header. |
Enumeration<Locale> |
getLocales()
Returns an
Enumeration of Locale objects
indicating, in decreasing order starting with the preferred locale, the
locales that are acceptable to the client based on the Accept-Language
header. |
String |
getLocalName()
Returns the host name of the Internet Protocol (IP) interface on
which the request was received.
|
int |
getLocalPort()
Returns the Internet Protocol (IP) port number of the interface
on which the request was received.
|
String |
getParameter(String name)
Returns the value of a request parameter as a
String ,
or null if the parameter does not exist. |
Map<String,String[]> |
getParameterMap()
Returns a java.util.Map of the parameters of this request.
|
Enumeration<String> |
getParameterNames()
Returns an
Enumeration of String
objects containing the names of the parameters contained
in this request. |
String[] |
getParameterValues(String name)
Returns an array of
String objects containing
all of the values the given request parameter has, or
null if the parameter does not exist. |
String |
getProtocol()
Returns the name and version of the protocol the request uses
in the form protocol/majorVersion.minorVersion, for
example, HTTP/1.1.
|
BufferedReader |
getReader()
Retrieves the body of the request as character data using
a
BufferedReader . |
String |
getRealPath(String path)
Deprecated.
As of Version 2.1 of the Java Servlet API,
use
ServletContext.getRealPath(java.lang.String) instead. |
String |
getRemoteAddr()
Returns the Internet Protocol (IP) address of the client
or last proxy that sent the request.
|
String |
getRemoteHost()
Returns the fully qualified name of the client
or the last proxy that sent the request.
|
int |
getRemotePort()
Returns the Internet Protocol (IP) source port of the client
or last proxy that sent the request.
|
RequestDispatcher |
getRequestDispatcher(String path)
Returns a
RequestDispatcher object that acts as a wrapper for
the resource located at the given path. |
String |
getScheme()
Returns the name of the scheme used to make this request,
for example,
http , https , or ftp . |
String |
getServerName()
Returns the host name of the server to which the request was sent.
|
int |
getServerPort()
Returns the port number to which the request was sent.
|
ServletContext |
getServletContext()
Gets the servlet context to which this ServletRequest was last
dispatched.
|
boolean |
isAsyncStarted()
Checks if this request has been put into asynchronous mode.
|
boolean |
isAsyncSupported()
Checks if this request supports asynchronous operation.
|
boolean |
isSecure()
Returns a boolean indicating whether this request was made using a
secure channel, such as HTTPS.
|
void |
removeAttribute(String name)
Removes an attribute from this request.
|
void |
setAttribute(String name,
Object o)
Stores an attribute in this request.
|
void |
setCharacterEncoding(String env)
Overrides the name of the character encoding used in the body of this
request.
|
AsyncContext |
startAsync()
Puts this request into asynchronous mode, and initializes its
AsyncContext with the original (unwrapped) ServletRequest
and ServletResponse objects. |
AsyncContext |
startAsync(ServletRequest servletRequest,
ServletResponse servletResponse)
Puts this request into asynchronous mode, and initializes its
AsyncContext with the given request and response objects. |
Object getAttribute(String name)
Object
,
or null
if no attribute of the given name exists.
Attributes can be set two ways. The servlet container may set
attributes to make available custom information about a request.
For example, for requests made using HTTPS, the attribute
javax.servlet.request.X509Certificate
can be used to
retrieve information on the certificate of the client. Attributes
can also be set programatically using
setAttribute(java.lang.String, java.lang.Object)
. This allows information to be
embedded into a request before a RequestDispatcher
call.
Attribute names should follow the same conventions as package
names. This specification reserves names matching java.*
,
javax.*
, and sun.*
.
name
- a String
specifying the name of the attributeObject
containing the value of the attribute,
or null
if the attribute does not existEnumeration<String> getAttributeNames()
Enumeration
containing the
names of the attributes available to this request.
This method returns an empty Enumeration
if the request has no attributes available to it.Enumeration
of strings containing the names
of the request's attributesString getCharacterEncoding()
null
if the request
does not specify a character encodingString
containing the name of the character
encoding, or null
if the request does not specify a
character encodingvoid setCharacterEncoding(String env) throws UnsupportedEncodingException
env
- String
containing the name of
the character encoding.UnsupportedEncodingException
- if this ServletRequest is still
in a state where a character encoding may be set,
but the specified encoding is invalidint getContentLength()
long getContentLengthLong()
String getContentType()
null
if the type is not known. For HTTP servlets,
same as the value of the CGI variable CONTENT_TYPE.String
containing the name of the MIME type
of the request, or null if the type is not knownServletInputStream getInputStream() throws IOException
ServletInputStream
. Either this method or
getReader()
may be called to read the body, not both.ServletInputStream
object containing
the body of the requestIllegalStateException
- if the getReader()
method
has already been called for this requestIOException
- if an input or output exception occurredString getParameter(String name)
String
,
or null
if the parameter does not exist. Request parameters
are extra information sent with the request. For HTTP servlets,
parameters are contained in the query string or posted form data.
You should only use this method when you are sure the
parameter has only one value. If the parameter might have
more than one value, use getParameterValues(java.lang.String)
.
If you use this method with a multivalued
parameter, the value returned is equal to the first value
in the array returned by getParameterValues
.
If the parameter data was sent in the request body, such as occurs
with an HTTP POST request, then reading the body directly via getInputStream()
or getReader()
can interfere
with the execution of this method.
name
- a String
specifying the name of the parameterString
representing the single value of
the parametergetParameterValues(java.lang.String)
Enumeration<String> getParameterNames()
Enumeration
of String
objects containing the names of the parameters contained
in this request. If the request has
no parameters, the method returns an empty Enumeration
.Enumeration
of String
objects, each String
containing the name of
a request parameter; or an empty Enumeration
if the request has no parametersString[] getParameterValues(String name)
String
objects containing
all of the values the given request parameter has, or
null
if the parameter does not exist.
If the parameter has a single value, the array has a length of 1.
name
- a String
containing the name of
the parameter whose value is requestedString
objects
containing the parameter's valuesgetParameter(java.lang.String)
Map<String,String[]> getParameterMap()
Request parameters are extra information sent with the request. For HTTP servlets, parameters are contained in the query string or posted form data.
String getProtocol()
SERVER_PROTOCOL
.String
containing the protocol
name and version numberString getScheme()
http
, https
, or ftp
.
Different schemes have different rules for constructing URLs,
as noted in RFC 1738.String
containing the name
of the scheme used to make this requestString getServerName()
Host
header value, if any, or the resolved server name, or the server IP
address.String
containing the name of the serverint getServerPort()
Host
header value, if any, or the server port where the client connection
was accepted on.BufferedReader getReader() throws IOException
BufferedReader
. The reader translates the character
data according to the character encoding used on the body.
Either this method or getInputStream()
may be called to read the
body, not both.BufferedReader
containing the body of the requestUnsupportedEncodingException
- if the character set encoding
used is not supported and the text cannot be decodedIllegalStateException
- if getInputStream()
method
has been called on this requestIOException
- if an input or output exception occurredgetInputStream()
String getRemoteAddr()
REMOTE_ADDR
.String
containing the
IP address of the client that sent the requestString getRemoteHost()
REMOTE_HOST
.String
containing the fully
qualified name of the clientvoid setAttribute(String name, Object o)
RequestDispatcher
.
Attribute names should follow the same conventions as
package names. Names beginning with java.*
,
javax.*
, and com.sun.*
, are
reserved for use by Sun Microsystems.
If the object passed in is null, the effect is the same as
calling removeAttribute(java.lang.String)
.
It is warned that when the request is dispatched from the
servlet resides in a different web application by
RequestDispatcher
, the object set by this method
may not be correctly retrieved in the caller servlet.
name
- a String
specifying
the name of the attributeo
- the Object
to be storedvoid removeAttribute(String name)
Attribute names should follow the same conventions as
package names. Names beginning with java.*
,
javax.*
, and com.sun.*
, are
reserved for use by Sun Microsystems.
name
- a String
specifying
the name of the attribute to removeLocale getLocale()
Locale
that the client will
accept content in, based on the Accept-Language header.
If the client request doesn't provide an Accept-Language header,
this method returns the default locale for the server.Locale
for the clientEnumeration<Locale> getLocales()
Enumeration
of Locale
objects
indicating, in decreasing order starting with the preferred locale, the
locales that are acceptable to the client based on the Accept-Language
header.
If the client request doesn't provide an Accept-Language header,
this method returns an Enumeration
containing one
Locale
, the default locale for the server.Enumeration
of preferred
Locale
objects for the clientboolean isSecure()
RequestDispatcher getRequestDispatcher(String path)
RequestDispatcher
object that acts as a wrapper for
the resource located at the given path.
A RequestDispatcher
object can be used to forward
a request to the resource or to include the resource in a response.
The resource can be dynamic or static.
The pathname specified may be relative, although it cannot extend
outside the current servlet context. If the path begins with
a "/" it is interpreted as relative to the current context root.
This method returns null
if the servlet container
cannot return a RequestDispatcher
.
The difference between this method and ServletContext.getRequestDispatcher(java.lang.String)
is that this method can take a
relative path.
path
- a String
specifying the pathname
to the resource. If it is relative, it must be
relative against the current servlet.RequestDispatcher
object that acts as a
wrapper for the resource at the specified path,
or null
if the servlet container cannot
return a RequestDispatcher
RequestDispatcher
,
ServletContext.getRequestDispatcher(java.lang.String)
String getRealPath(String path)
ServletContext.getRealPath(java.lang.String)
instead.int getRemotePort()
String getLocalName()
String
containing the host
name of the IP on which the request was received.String getLocalAddr()
String
containing the
IP address on which the request was received.int getLocalPort()
ServletContext getServletContext()
AsyncContext startAsync() throws IllegalStateException
AsyncContext
with the original (unwrapped) ServletRequest
and ServletResponse objects.
Calling this method will cause committal of the associated
response to be delayed until AsyncContext.complete()
is
called on the returned AsyncContext
, or the asynchronous
operation has timed out.
Calling AsyncContext.hasOriginalRequestAndResponse()
on
the returned AsyncContext will return true
. Any filters
invoked in the outbound direction after this request was put
into asynchronous mode may use this as an indication that any request
and/or response wrappers that they added during their inbound
invocation need not stay around for the duration of the asynchronous
operation, and therefore any of their associated resources may be
released.
This method clears the list of AsyncListener
instances
(if any) that were registered with the AsyncContext returned by the
previous call to one of the startAsync methods, after calling each
AsyncListener at its onStartAsync
method.
Subsequent invocations of this method, or its overloaded variant, will return the same AsyncContext instance, reinitialized as appropriate.
IllegalStateException
- if this request is within the scope of
a filter or servlet that does not support asynchronous operations
(that is, isAsyncSupported()
returns false),
or if this method is called again without any asynchronous dispatch
(resulting from one of the AsyncContext.dispatch()
methods),
is called outside the scope of any such dispatch, or is called again
within the scope of the same dispatch, or if the response has
already been closedAsyncContext.dispatch()
AsyncContext startAsync(ServletRequest servletRequest, ServletResponse servletResponse) throws IllegalStateException
AsyncContext
with the given request and response objects.
The ServletRequest and ServletResponse arguments must be
the same instances, or instances of ServletRequestWrapper
and
ServletResponseWrapper
that wrap them, that were passed to the
service
method of the Servlet or the
doFilter
method of the Filter, respectively,
in whose scope this method is being called.
Calling this method will cause committal of the associated
response to be delayed until AsyncContext.complete()
is
called on the returned AsyncContext
, or the asynchronous
operation has timed out.
Calling AsyncContext.hasOriginalRequestAndResponse()
on
the returned AsyncContext will return false
,
unless the passed in ServletRequest and ServletResponse arguments
are the original ones or do not carry any application-provided wrappers.
Any filters invoked in the outbound direction after this
request was put into asynchronous mode may use this as an indication
that some of the request and/or response wrappers that they added
during their inbound invocation may need to stay in place for
the duration of the asynchronous operation, and their associated
resources may not be released.
A ServletRequestWrapper applied during the inbound
invocation of a filter may be released by the outbound
invocation of the filter only if the given servletRequest
,
which is used to initialize the AsyncContext and will be returned by
a call to AsyncContext.getRequest()
, does not contain said
ServletRequestWrapper. The same holds true for ServletResponseWrapper
instances.
This method clears the list of AsyncListener
instances
(if any) that were registered with the AsyncContext returned by the
previous call to one of the startAsync methods, after calling each
AsyncListener at its onStartAsync
method.
Subsequent invocations of this method, or its zero-argument variant, will return the same AsyncContext instance, reinitialized as appropriate. If a call to this method is followed by a call to its zero-argument variant, the specified (and possibly wrapped) request and response objects will remain locked in on the returned AsyncContext.
servletRequest
- the ServletRequest used to initialize the
AsyncContextservletResponse
- the ServletResponse used to initialize the
AsyncContextIllegalStateException
- if this request is within the scope of
a filter or servlet that does not support asynchronous operations
(that is, isAsyncSupported()
returns false),
or if this method is called again without any asynchronous dispatch
(resulting from one of the AsyncContext.dispatch()
methods),
is called outside the scope of any such dispatch, or is called again
within the scope of the same dispatch, or if the response has
already been closedboolean isAsyncStarted()
A ServletRequest is put into asynchronous mode by calling
startAsync()
or
startAsync(ServletRequest,ServletResponse)
on it.
This method returns false if this request was
put into asynchronous mode, but has since been dispatched using
one of the AsyncContext.dispatch()
methods or released
from asynchronous mode via a call to AsyncContext.complete()
.
boolean isAsyncSupported()
Asynchronous operation is disabled for this request if this request is within the scope of a filter or servlet that has not been annotated or flagged in the deployment descriptor as being able to support asynchronous handling.
AsyncContext getAsyncContext()
startAsync()
or
startAsync(ServletRequest,ServletResponse)
on this request.startAsync()
or
startAsync(ServletRequest,ServletResponse)
on
this requestIllegalStateException
- if this request has not been put
into asynchronous mode, i.e., if neither startAsync()
nor
startAsync(ServletRequest,ServletResponse)
has been calledDispatcherType getDispatcherType()
The dispatcher type of a request is used by the container to select the filters that need to be applied to the request: Only filters with matching dispatcher type and url patterns will be applied.
Allowing a filter that has been configured for multiple dispatcher types to query a request for its dispatcher type allows the filter to process the request differently depending on its dispatcher type.
The initial dispatcher type of a request is defined as
DispatcherType.REQUEST
. The dispatcher type of a request
dispatched via RequestDispatcher.forward(ServletRequest,
ServletResponse)
or RequestDispatcher.include(ServletRequest,
ServletResponse)
is given as DispatcherType.FORWARD
or
DispatcherType.INCLUDE
, respectively, while the
dispatcher type of an asynchronous request dispatched via
one of the AsyncContext.dispatch()
methods is given as
DispatcherType.ASYNC
. Finally, the dispatcher type of a
request dispatched to an error page by the container's error handling
mechanism is given as DispatcherType.ERROR
.
DispatcherType
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