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javax.servlet Interface ServletResponse
- All Known Subinterfaces:
- HttpServletResponse
- All Known Implementing Classes:
- ServletResponseWrapper
- public abstract interface ServletResponse
Defines an object to assist a servlet in sending a response to the client.
The servlet container creates a ServletResponse
object and
passes it as an argument to the servlet's service
method.
To send binary data in a MIME body response, use
the ServletOutputStream
returned by getOutputStream()
.
To send character data, use the PrintWriter
object
returned by getWriter()
. To mix binary and text data,
for example, to create a multipart response, use a
ServletOutputStream
and manage the character sections
manually.
The charset for the MIME body response can be specified with
setContentType(java.lang.String)
. For example, "text/html; charset=Shift_JIS".
The charset can alternately be set using setLocale(java.util.Locale)
.
If no charset is specified, ISO-8859-1 will be used.
The setContentType
or setLocale
method
must be called before getWriter
for the charset to
affect the construction of the writer.
See the Internet RFCs such as RFC 2045 for more information on MIME. Protocols such as SMTP and HTTP define profiles of MIME, and those standards are still evolving.
- See Also:
ServletOutputStream
Method Summary | |
void |
flushBuffer()
Forces any content in the buffer to be written to the client. |
int |
getBufferSize()
Returns the actual buffer size used for the response. |
java.lang.String |
getCharacterEncoding()
Returns the name of the charset used for the MIME body sent in this response. |
java.util.Locale |
getLocale()
Returns the locale assigned to the response. |
ServletOutputStream |
getOutputStream()
Returns a ServletOutputStream suitable for writing binary
data in the response. |
java.io.PrintWriter |
getWriter()
Returns a PrintWriter object that
can send character text to the client. |
boolean |
isCommitted()
Returns a boolean indicating if the response has been committed. |
void |
reset()
Clears any data that exists in the buffer as well as the status code and headers. |
void |
resetBuffer()
Clears the content of the underlying buffer in the response without clearing headers or status code. |
void |
setBufferSize(int size)
Sets the preferred buffer size for the body of the response. |
void |
setContentLength(int len)
Sets the length of the content body in the response In HTTP servlets, this method sets the HTTP Content-Length header. |
void |
setContentType(java.lang.String type)
Sets the content type of the response being sent to the client. |
void |
setLocale(java.util.Locale loc)
Sets the locale of the response, setting the headers (including the Content-Type's charset) as appropriate. |
Method Detail |
getCharacterEncoding
public java.lang.String getCharacterEncoding()
- Returns the name of the charset used for
the MIME body sent in this response.
If no charset has been assigned, it is implicitly set to
ISO-8859-1
(Latin-1
).See RFC 2047 (http://ds.internic.net/rfc/rfc2045.txt) for more information about character encoding and MIME.
- Returns:
- a
String
specifying the name of the charset, for example,ISO-8859-1
getOutputStream
public ServletOutputStream getOutputStream() throws java.io.IOException
- Returns a
ServletOutputStream
suitable for writing binary data in the response. The servlet container does not encode the binary data.Calling flush() on the ServletOutputStream commits the response. Either this method or
getWriter()
may be called to write the body, not both. - Returns:
- a
ServletOutputStream
for writing binary data - Throws:
- IllegalStateException - if the
getWriter
method has been called on this response - java.io.IOException - if an input or output exception occurred
- See Also:
getWriter()
getWriter
public java.io.PrintWriter getWriter() throws java.io.IOException
- Returns a
PrintWriter
object that can send character text to the client. The character encoding used is the one specified in thecharset=
property of thesetContentType(java.lang.String)
method, which must be called before calling this method for the charset to take effect.If necessary, the MIME type of the response is modified to reflect the character encoding used.
Calling flush() on the PrintWriter commits the response.
Either this method or
getOutputStream()
may be called to write the body, not both. - Returns:
- a
PrintWriter
object that can return character data to the client - Throws:
- java.io.UnsupportedEncodingException - if the charset specified in
setContentType
cannot be used - IllegalStateException - if the
getOutputStream
method has already been called for this response object - java.io.IOException - if an input or output exception occurred
- See Also:
getOutputStream()
,setContentType(java.lang.String)
setContentLength
public void setContentLength(int len)
- Sets the length of the content body in the response In HTTP servlets, this method sets the HTTP Content-Length header.
- Parameters:
len
- an integer specifying the length of the content being returned to the client; sets the Content-Length header
setContentType
public void setContentType(java.lang.String type)
- Sets the content type of the response being sent to
the client. The content type may include the type of character
encoding used, for example,
text/html; charset=ISO-8859-4
.If obtaining a
PrintWriter
, this method should be called first. - Parameters:
type
- aString
specifying the MIME type of the content- See Also:
getOutputStream()
,getWriter()
setBufferSize
public void setBufferSize(int size)
- Sets the preferred buffer size for the body of the response.
The servlet container will use a buffer at least as large as
the size requested. The actual buffer size used can be found
using
getBufferSize
.A larger buffer allows more content to be written before anything is actually sent, thus providing the servlet with more time to set appropriate status codes and headers. A smaller buffer decreases server memory load and allows the client to start receiving data more quickly.
This method must be called before any response body content is written; if content has been written, this method throws an
IllegalStateException
. - Parameters:
size
- the preferred buffer size- Throws:
- IllegalStateException - if this method is called after content has been written
- See Also:
getBufferSize()
,flushBuffer()
,isCommitted()
,reset()
getBufferSize
public int getBufferSize()
- Returns the actual buffer size used for the response. If no buffering is used, this method returns 0.
- Returns:
- the actual buffer size used
- See Also:
setBufferSize(int)
,flushBuffer()
,isCommitted()
,reset()
flushBuffer
public void flushBuffer() throws java.io.IOException
- Forces any content in the buffer to be written to the client. A call to this method automatically commits the response, meaning the status code and headers will be written.
- See Also:
setBufferSize(int)
,getBufferSize()
,isCommitted()
,reset()
resetBuffer
public void resetBuffer()
- Clears the content of the underlying buffer in the response without
clearing headers or status code. If the
response has been committed, this method throws an
IllegalStateException
. - Since:
- 2.3
- See Also:
setBufferSize(int)
,getBufferSize()
,isCommitted()
,reset()
isCommitted
public boolean isCommitted()
- Returns a boolean indicating if the response has been committed. A commited response has already had its status code and headers written.
- Returns:
- a boolean indicating if the response has been committed
- See Also:
setBufferSize(int)
,getBufferSize()
,flushBuffer()
,reset()
reset
public void reset()
- Clears any data that exists in the buffer as well as the status code and
headers. If the response has been committed, this method throws an
IllegalStateException
. - Throws:
- IllegalStateException - if the response has already been committed
- See Also:
setBufferSize(int)
,getBufferSize()
,flushBuffer()
,isCommitted()
setLocale
public void setLocale(java.util.Locale loc)
- Sets the locale of the response, setting the headers (including the
Content-Type's charset) as appropriate. This method should be called
before a call to
getWriter()
. By default, the response locale is the default locale for the server. - Parameters:
loc
- the locale of the response- See Also:
getLocale()
getLocale
public java.util.Locale getLocale()
- Returns the locale assigned to the response.
- See Also:
setLocale(java.util.Locale)
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