Java net httpurlconnection example

Java net httpurlconnection example

If automatic redirection is enabled, and this request is redirected to another destination, then the caller must also have permission to connect to the redirected host/URL.

Field Summary

Fields inherited from class java.net.URLConnection

Constructor Summary

Method Summary

Returns a SocketPermission object representing the permission necessary to connect to the destination host and port.

This method is used to enable streaming of a HTTP request body without internal buffering, when the content length is not known in advance.

This method is used to enable streaming of a HTTP request body without internal buffering, when the content length is known in advance.

This method is used to enable streaming of a HTTP request body without internal buffering, when the content length is known in advance.

Sets whether HTTP redirects (requests with response code 3xx) should be automatically followed by this class.

Sets whether HTTP redirects (requests with response code 3xx) should be automatically followed by this HttpURLConnection instance.

Set the method for the URL request, one of: GET POST HEAD OPTIONS PUT DELETE TRACE are legal, subject to protocol restrictions.

Methods inherited from class java.net.URLConnection

Methods inherited from class java.lang.Object

Field Detail

method

chunkLength

protected int chunkLength

The chunk-length when using chunked encoding streaming mode for output. A value of -1 means chunked encoding is disabled for output.

fixedContentLength

protected int fixedContentLength

The fixed content-length when using fixed-length streaming mode. A value of -1 means fixed-length streaming mode is disabled for output. NOTE: fixedContentLengthLong is recommended instead of this field, as it allows larger content lengths to be set.

fixedContentLengthLong

protected long fixedContentLengthLong

The fixed content-length when using fixed-length streaming mode. A value of -1 means fixed-length streaming mode is disabled for output.

responseCode

protected int responseCode

• 1xx: Informational
• 2xx: Success
• 3xx: Redirection
• 4xx: Client Error
• 5xx: Server Error

responseMessage

instanceFollowRedirects

protected boolean instanceFollowRedirects

If true , the protocol will automatically follow redirects. If false , the protocol will not automatically follow redirects. This field is set by the setInstanceFollowRedirects method. Its value is returned by the getInstanceFollowRedirects method. Its default value is based on the value of the static followRedirects at HttpURLConnection construction time.

HTTP_OK

public static final int HTTP_OK

HTTP_CREATED

public static final int HTTP_CREATED

HTTP_ACCEPTED

public static final int HTTP_ACCEPTED

HTTP_NOT_AUTHORITATIVE

public static final int HTTP_NOT_AUTHORITATIVE

HTTP_NO_CONTENT

public static final int HTTP_NO_CONTENT

HTTP_RESET

public static final int HTTP_RESET

HTTP_PARTIAL

public static final int HTTP_PARTIAL

HTTP_MULT_CHOICE

public static final int HTTP_MULT_CHOICE

HTTP_MOVED_PERM

public static final int HTTP_MOVED_PERM

HTTP_MOVED_TEMP

public static final int HTTP_MOVED_TEMP

HTTP_SEE_OTHER

public static final int HTTP_SEE_OTHER

HTTP_NOT_MODIFIED

public static final int HTTP_NOT_MODIFIED

HTTP_USE_PROXY

public static final int HTTP_USE_PROXY

HTTP_BAD_REQUEST

public static final int HTTP_BAD_REQUEST

HTTP_UNAUTHORIZED

public static final int HTTP_UNAUTHORIZED

HTTP_PAYMENT_REQUIRED

public static final int HTTP_PAYMENT_REQUIRED

HTTP_FORBIDDEN

public static final int HTTP_FORBIDDEN

HTTP_NOT_FOUND

public static final int HTTP_NOT_FOUND

HTTP_BAD_METHOD

public static final int HTTP_BAD_METHOD

HTTP_NOT_ACCEPTABLE

public static final int HTTP_NOT_ACCEPTABLE

HTTP_PROXY_AUTH

public static final int HTTP_PROXY_AUTH

HTTP_CLIENT_TIMEOUT

public static final int HTTP_CLIENT_TIMEOUT

HTTP_CONFLICT

public static final int HTTP_CONFLICT

HTTP_GONE

public static final int HTTP_GONE

HTTP_LENGTH_REQUIRED

public static final int HTTP_LENGTH_REQUIRED

HTTP_PRECON_FAILED

public static final int HTTP_PRECON_FAILED

HTTP_ENTITY_TOO_LARGE

public static final int HTTP_ENTITY_TOO_LARGE

HTTP_REQ_TOO_LONG

public static final int HTTP_REQ_TOO_LONG

HTTP_UNSUPPORTED_TYPE

public static final int HTTP_UNSUPPORTED_TYPE

HTTP_SERVER_ERROR

@Deprecated public static final int HTTP_SERVER_ERROR

HTTP_INTERNAL_ERROR

public static final int HTTP_INTERNAL_ERROR

HTTP_NOT_IMPLEMENTED

public static final int HTTP_NOT_IMPLEMENTED

HTTP_BAD_GATEWAY

public static final int HTTP_BAD_GATEWAY

HTTP_UNAVAILABLE

public static final int HTTP_UNAVAILABLE

HTTP_GATEWAY_TIMEOUT

public static final int HTTP_GATEWAY_TIMEOUT

HTTP_VERSION

public static final int HTTP_VERSION

Constructor Detail

HttpURLConnection

Method Detail

getHeaderFieldKey

Returns the key for the n th header field. Some implementations may treat the 0 th header field as special, i.e. as the status line returned by the HTTP server. In this case, getHeaderField(0) returns the status line, but getHeaderFieldKey(0) returns null.

setFixedLengthStreamingMode

public void setFixedLengthStreamingMode(int contentLength)

This method is used to enable streaming of a HTTP request body without internal buffering, when the content length is known in advance. An exception will be thrown if the application attempts to write more data than the indicated content-length, or if the application closes the OutputStream before writing the indicated amount. When output streaming is enabled, authentication and redirection cannot be handled automatically. A HttpRetryException will be thrown when reading the response if authentication or redirection are required. This exception can be queried for the details of the error. This method must be called before the URLConnection is connected. NOTE: setFixedLengthStreamingMode(long) is recommended instead of this method as it allows larger content lengths to be set.

setFixedLengthStreamingMode

public void setFixedLengthStreamingMode(long contentLength)

This method is used to enable streaming of a HTTP request body without internal buffering, when the content length is known in advance. An exception will be thrown if the application attempts to write more data than the indicated content-length, or if the application closes the OutputStream before writing the indicated amount. When output streaming is enabled, authentication and redirection cannot be handled automatically. A HttpRetryException will be thrown when reading the response if authentication or redirection are required. This exception can be queried for the details of the error. This method must be called before the URLConnection is connected. The content length set by invoking this method takes precedence over any value set by setFixedLengthStreamingMode(int) .

setChunkedStreamingMode

public void setChunkedStreamingMode(int chunklen)

This method is used to enable streaming of a HTTP request body without internal buffering, when the content length is not known in advance. In this mode, chunked transfer encoding is used to send the request body. Note, not all HTTP servers support this mode. When output streaming is enabled, authentication and redirection cannot be handled automatically. A HttpRetryException will be thrown when reading the response if authentication or redirection are required. This exception can be queried for the details of the error. This method must be called before the URLConnection is connected.

getHeaderField

Returns the value for the n th header field. Some implementations may treat the 0 th header field as special, i.e. as the status line returned by the HTTP server. This method can be used in conjunction with the getHeaderFieldKey method to iterate through all the headers in the message.

setFollowRedirects

public static void setFollowRedirects(boolean set)

Sets whether HTTP redirects (requests with response code 3xx) should be automatically followed by this class. True by default. Applets cannot change this variable. If there is a security manager, this method first calls the security manager’s checkSetFactory method to ensure the operation is allowed. This could result in a SecurityException.

getFollowRedirects

public static boolean getFollowRedirects()

setInstanceFollowRedirects

public void setInstanceFollowRedirects(boolean followRedirects)

Sets whether HTTP redirects (requests with response code 3xx) should be automatically followed by this HttpURLConnection instance. The default value comes from followRedirects, which defaults to true.

getInstanceFollowRedirects

public boolean getInstanceFollowRedirects()

setRequestMethod

public void setRequestMethod(String method) throws ProtocolException

getRequestMethod

getResponseCode

Gets the status code from an HTTP response message. For example, in the case of the following status lines:

HTTP/1.0 200 OK HTTP/1.0 401 Unauthorized

It will return 200 and 401 respectively. Returns -1 if no code can be discerned from the response (i.e., the response is not valid HTTP).

getResponseMessage

public String getResponseMessage() throws IOException

Gets the HTTP response message, if any, returned along with the response code from a server. From responses like:

HTTP/1.0 200 OK HTTP/1.0 404 Not Found

Extracts the Strings «OK» and «Not Found» respectively. Returns null if none could be discerned from the responses (the result was not valid HTTP).

getHeaderFieldDate

Returns the value of the named field parsed as date. The result is the number of milliseconds since January 1, 1970 GMT represented by the named field. This form of getHeaderField exists because some connection types (e.g., http-ng ) have pre-parsed headers. Classes for that connection type can override this method and short-circuit the parsing.

disconnect

public abstract void disconnect()

Indicates that other requests to the server are unlikely in the near future. Calling disconnect() should not imply that this HttpURLConnection instance can be reused for other requests.

usingProxy

public abstract boolean usingProxy()

getPermission

public Permission getPermission() throws IOException

Returns a SocketPermission object representing the permission necessary to connect to the destination host and port.

getErrorStream

Returns the error stream if the connection failed but the server sent useful data nonetheless. The typical example is when an HTTP server responds with a 404, which will cause a FileNotFoundException to be thrown in connect, but the server sent an HTML help page with suggestions as to what to do. This method will not cause a connection to be initiated. If the connection was not connected, or if the server did not have an error while connecting or if the server had an error but no error data was sent, this method will return null. This is the default.

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