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Class HTTPClient.HttpURLConnection
java.lang.Object
|
+----java.net.URLConnection
|
+----java.net.HttpURLConnection
|
+----HTTPClient.HttpURLConnection
- public class HttpURLConnection
- extends HttpURLConnection
- implements GlobalConstants
This class is a wrapper around HTTPConnection providing the interface
defined by java.net.URLConnection and java.net.HttpURLConnection.
This class can be used to replace the HttpClient in the JDK with this
HTTPClient by defining the property
java.protocol.handler.pkgs=HTTPClient
.
One difference between Sun's HttpClient and this one is that this
one will provide you with a real output stream if possible. This leads
to two changes: you should set the request property "Content-Length",
if possible, before invoking getOutputStream(); and in many cases
getOutputStream() implies connect(). This should be transparent, though,
apart from the fact that you can't change any headers or other settings
anymore once you've gotten the output stream.
So, for large data do:
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setDoOutput(true);
con.setRequestProperty("Content-Length", ...);
OutputStream out = con.getOutputStream();
out.write(...);
out.close();
if (con.getResponseCode() != 200)
...
The HTTPClient will send the request data using the chunked transfer
encoding when no Content-Length is specified and the server is HTTP/1.1
compatible. Because cgi-scripts can't usually handle this, you may
experience problems trying to POST data. For this reason, whenever
the Content-Type is application/x-www-form-urlencoded getOutputStream()
will buffer the data before sending it so as prevent chunking. If you
are sending requests with a different Content-Type and are experiencing
problems then you may want to try setting the system property
HTTPClient.dontChunkRequests to true (this needs
to be done either on the command line or somewhere in the code before
the first URLConnection.openConnection() is invoked).
- Version:
- 0.3-2 18/06/1999
- Author:
- Ronald Tschalär
-
HttpURLConnection(URL)
- Construct a connection to the specified url.
-
connect()
- Connects to the server (if connection not still kept alive) and
issues the request.
-
disconnect()
- Closes all the connections to this server.
-
getDefaultRequestProperty(String)
- Gets the value for a given default request header.
-
getErrorStream()
- Returns the error stream if the connection failed
but the server sent useful data nonetheless.
-
getHeaderField(int)
- Gets header value of the n-th header.
-
getHeaderField(String)
- Get the value part of a header.
-
getHeaderFieldDate(String, long)
- Get the value part of a header, interprets it as a date and converts
it to a long representing the number of milliseconds since 1970.
-
getHeaderFieldInt(String, int)
- Get the value part of a header and converts it to an int.
-
getHeaderFieldKey(int)
- Gets header name of the n-th header.
-
getInputStream()
- Gets an input stream from which the data in the response may be read.
-
getInstanceFollowRedirects()
-
-
getOutputStream()
- Gets an output stream which can be used send an entity with the
request.
-
getRequestMethod()
- Return the request method used.
-
getRequestProperty(String)
- Gets the value of a given request header.
-
getResponseCode()
- Get the response code.
-
getResponseMessage()
- Get the response message describing the response code.
-
getURL()
- Gets the url for this connection.
-
setDefaultRequestProperty(String, String)
- Sets an arbitrary default request header.
-
setIfModifiedSince(long)
- Sets the If-Modified-Since header.
-
setInstanceFollowRedirects(boolean)
- Enables or disables the automatic handling of redirection responses
for this instance only.
-
setRequestMethod(String)
- Sets the request method (e.g.
-
setRequestProperty(String, String)
- Sets an arbitrary request header.
-
toString()
- produces a string.
-
usingProxy()
- Shows if request are being made through an http proxy or directly.
HttpURLConnection
public HttpURLConnection(URL url) throws ProtocolNotSuppException, IOException
- Construct a connection to the specified url. A cache of
HTTPConnections is used to maximize the reuse of these across
multiple HttpURLConnections.
The default method is "GET".
- Parameters:
- url - the url of the request
- Throws: ProtocolNotSuppException
- if the protocol is not supported
setRequestMethod
public void setRequestMethod(String method) throws ProtocolException
- Sets the request method (e.g. "PUT" or "HEAD"). Can only be set
before connect() is called.
- Parameters:
- method - the http method.
- Throws: ProtocolException
- if already connected.
- Overrides:
- setRequestMethod in class HttpURLConnection
getRequestMethod
public String getRequestMethod()
- Return the request method used.
- Returns:
- the http method.
- Overrides:
- getRequestMethod in class HttpURLConnection
getResponseCode
public int getResponseCode() throws IOException
- Get the response code. Calls connect() if not connected.
- Returns:
- the http response code returned.
- Overrides:
- getResponseCode in class HttpURLConnection
getResponseMessage
public String getResponseMessage() throws IOException
- Get the response message describing the response code. Calls connect()
if not connected.
- Returns:
- the http response message returned with the response code.
- Overrides:
- getResponseMessage in class HttpURLConnection
getHeaderField
public String getHeaderField(String name)
- Get the value part of a header. Calls connect() if not connected.
- Parameters:
- name - the of the header.
- Returns:
- the value of the header, or null if no such header was returned.
- Overrides:
- getHeaderField in class URLConnection
getHeaderFieldInt
public int getHeaderFieldInt(String name,
int def)
- Get the value part of a header and converts it to an int. If the
header does not exist or if its value could not be converted to an
int then the default is returned. Calls connect() if not connected.
- Parameters:
- name - the of the header.
- def - the default value to return in case of an error.
- Returns:
- the value of the header, or null if no such header was returned.
- Overrides:
- getHeaderFieldInt in class URLConnection
getHeaderFieldDate
public long getHeaderFieldDate(String name,
long def)
- Get the value part of a header, interprets it as a date and converts
it to a long representing the number of milliseconds since 1970. If
the header does not exist or if its value could not be converted to a
date then the default is returned. Calls connect() if not connected.
- Parameters:
- name - the of the header.
- def - the default value to return in case of an error.
- Returns:
- the value of the header, or def in case of an error.
- Overrides:
- getHeaderFieldDate in class URLConnection
getHeaderFieldKey
public String getHeaderFieldKey(int n)
- Gets header name of the n-th header. Calls connect() if not connected.
The name of the 0-th header is null, even though it the
0-th header has a value.
- Parameters:
- n - which header to return.
- Returns:
- the header name, or null if not that many headers.
- Overrides:
- getHeaderFieldKey in class URLConnection
getHeaderField
public String getHeaderField(int n)
- Gets header value of the n-th header. Calls connect() if not connected.
The value of 0-th header is the Status-Line (e.g. "HTTP/1.1 200 Ok").
- Parameters:
- n - which header to return.
- Returns:
- the header value, or null if not that many headers.
- Overrides:
- getHeaderField in class URLConnection
getInputStream
public InputStream getInputStream() throws IOException
- Gets an input stream from which the data in the response may be read.
Calls connect() if not connected.
- Returns:
- an InputStream
- Throws: ProtocolException
- if input not enabled.
- Overrides:
- getInputStream in class URLConnection
- See Also:
- setDoInput
getErrorStream
public InputStream getErrorStream()
- Returns the error stream if the connection failed
but the server sent useful data nonetheless.
This method will not cause a connection to be initiated.
- Returns:
- an InputStream, or null if either the connection hasn't
been established yet or no error occured
- See Also:
- getErrorStream
getOutputStream
public synchronized OutputStream getOutputStream() throws IOException
- Gets an output stream which can be used send an entity with the
request. Can be called multiple times, in which case always the
same stream is returned.
The default request method changes to "POST" when this method is
called. Cannot be called after connect().
If no Content-type has been set it defaults to
application/x-www-form-urlencoded. Furthermore, if the
Content-type is application/x-www-form-urlencoded then all
output will be collected in a buffer before sending it to the server;
otherwise an HttpOutputStream is used.
- Returns:
- an OutputStream
- Throws: ProtocolException
- if already connect()'ed, if output is not
enabled or if the request method does not
support output.
- Overrides:
- getOutputStream in class URLConnection
- See Also:
- setDoOutput, HttpOutputStream
getURL
public URL getURL()
- Gets the url for this connection. If we're connect()'d and the request
was redirected then the url returned is that of the final request.
- Returns:
- the final url, or null if any exception occured.
- Overrides:
- getURL in class URLConnection
setIfModifiedSince
public void setIfModifiedSince(long time)
- Sets the If-Modified-Since header.
- Parameters:
- time - the number of milliseconds since 1970.
- Overrides:
- setIfModifiedSince in class URLConnection
setRequestProperty
public void setRequestProperty(String name,
String value)
- Sets an arbitrary request header.
- Parameters:
- name - the name of the header.
- value - the value for the header.
- Overrides:
- setRequestProperty in class URLConnection
getRequestProperty
public String getRequestProperty(String name)
- Gets the value of a given request header.
- Parameters:
- name - the name of the header.
- Returns:
- the value part of the header, or null if no such header.
- Overrides:
- getRequestProperty in class URLConnection
setDefaultRequestProperty
public static void setDefaultRequestProperty(String name,
String value)
- Sets an arbitrary default request header. All headers set here are
automatically sent with each request.
- Parameters:
- name - the name of the header.
- value - the value for the header.
getDefaultRequestProperty
public static String getDefaultRequestProperty(String name)
- Gets the value for a given default request header.
- Parameters:
- name - the name of the header.
- Returns:
- the value part of the header, or null if no such header.
setInstanceFollowRedirects
public void setInstanceFollowRedirects(boolean set)
- Enables or disables the automatic handling of redirection responses
for this instance only. Cannot be called after
connect()
.
- Parameters:
- set - enables automatic redirection handling if true.
getInstanceFollowRedirects
public boolean getInstanceFollowRedirects()
- Returns:
- true if automatic redirection handling for this instance is
enabled.
connect
public synchronized void connect() throws IOException
- Connects to the server (if connection not still kept alive) and
issues the request.
- Overrides:
- connect in class URLConnection
disconnect
public void disconnect()
- Closes all the connections to this server.
- Overrides:
- disconnect in class HttpURLConnection
usingProxy
public boolean usingProxy()
- Shows if request are being made through an http proxy or directly.
- Returns:
- true if an http proxy is being used.
- Overrides:
- usingProxy in class HttpURLConnection
toString
public String toString()
- produces a string.
- Returns:
- a string containing the HttpURLConnection
- Overrides:
- toString in class URLConnection
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