HttpURLConnection (ocap 1.3.1 API)

java.lang.Object
- java.net.URLConnection
- - java.net.HttpURLConnection

Direct Known Subclasses:

HttpsURLConnection
```
public abstract class HttpURLConnection
extends URLConnection
```
A URLConnection with support for HTTP-specific features. See the spec for details.
Each HttpURLConnection instance is used to make a single request but the underlying network connection to the HTTP server may be transparently shared by other instances. Calling the close() methods on the InputStream or OutputStream of an HttpURLConnection after a request may free network resources associated with this instance but has no effect on any shared persistent connection. Calling the disconnect() method may close the underlying socket if a persistent connection is otherwise idle at that time.

Since:

JDK1.1

See Also:
disconnect()

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`HTTP_ACCEPTED` HTTP Status-Code 202: Accepted.
`static int`	`HTTP_BAD_GATEWAY` HTTP Status-Code 502: Bad Gateway.
`static int`	`HTTP_BAD_METHOD` HTTP Status-Code 405: Method Not Allowed.
`static int`	`HTTP_BAD_REQUEST` HTTP Status-Code 400: Bad Request.
`static int`	`HTTP_CLIENT_TIMEOUT` HTTP Status-Code 408: Request Time-Out.
`static int`	`HTTP_CONFLICT` HTTP Status-Code 409: Conflict.
`static int`	`HTTP_CREATED` HTTP Status-Code 201: Created.
`static int`	`HTTP_ENTITY_TOO_LARGE` HTTP Status-Code 413: Request Entity Too Large.
`static int`	`HTTP_FORBIDDEN` HTTP Status-Code 403: Forbidden.
`static int`	`HTTP_GATEWAY_TIMEOUT` HTTP Status-Code 504: Gateway Timeout.
`static int`	`HTTP_GONE` HTTP Status-Code 410: Gone.
`static int`	`HTTP_INTERNAL_ERROR` HTTP Status-Code 500: Internal Server Error.
`static int`	`HTTP_LENGTH_REQUIRED` HTTP Status-Code 411: Length Required.
`static int`	`HTTP_MOVED_PERM` HTTP Status-Code 301: Moved Permanently.
`static int`	`HTTP_MOVED_TEMP` HTTP Status-Code 302: Temporary Redirect.
`static int`	`HTTP_MULT_CHOICE` HTTP Status-Code 300: Multiple Choices.
`static int`	`HTTP_NO_CONTENT` HTTP Status-Code 204: No Content.
`static int`	`HTTP_NOT_ACCEPTABLE` HTTP Status-Code 406: Not Acceptable.
`static int`	`HTTP_NOT_AUTHORITATIVE` HTTP Status-Code 203: Non-Authoritative Information.
`static int`	`HTTP_NOT_FOUND` HTTP Status-Code 404: Not Found.
`static int`	`HTTP_NOT_IMPLEMENTED` HTTP Status-Code 501: Not Implemented.
`static int`	`HTTP_NOT_MODIFIED` HTTP Status-Code 304: Not Modified.
`static int`	`HTTP_OK` HTTP Status-Code 200: OK.
`static int`	`HTTP_PARTIAL` HTTP Status-Code 206: Partial Content.
`static int`	`HTTP_PAYMENT_REQUIRED` HTTP Status-Code 402: Payment Required.
`static int`	`HTTP_PRECON_FAILED` HTTP Status-Code 412: Precondition Failed.
`static int`	`HTTP_PROXY_AUTH` HTTP Status-Code 407: Proxy Authentication Required.
`static int`	`HTTP_REQ_TOO_LONG` HTTP Status-Code 414: Request-URI Too Large.
`static int`	`HTTP_RESET` HTTP Status-Code 205: Reset Content.
`static int`	`HTTP_SEE_OTHER` HTTP Status-Code 303: See Other.
`static int`	`HTTP_UNAUTHORIZED` HTTP Status-Code 401: Unauthorized.
`static int`	`HTTP_UNAVAILABLE` HTTP Status-Code 503: Service Unavailable.
`static int`	`HTTP_UNSUPPORTED_TYPE` HTTP Status-Code 415: Unsupported Media Type.
`static int`	`HTTP_USE_PROXY` HTTP Status-Code 305: Use Proxy.
`static int`	`HTTP_VERSION` HTTP Status-Code 505: HTTP Version Not Supported.
`protected boolean`	`instanceFollowRedirects` If `true`, the protocol will automatically follow redirects.
`protected String`	`method` The HTTP method (GET,POST,PUT,etc.).
`protected int`	`responseCode` An `int` representing the three digit HTTP Status-Code.
`protected String`	`responseMessage` The HTTP response message.

Fields inherited from class java.net.URLConnection
allowUserInteraction, connected, doInput, doOutput, ifModifiedSince, url, useCaches

Constructor Summary

Constructors
Modifier Constructor and Description

protected HttpURLConnection(URL u)
Constructor for the HttpURLConnection.

Constructors
Modifier	Constructor and Description
`protected`	`HttpURLConnection(URL u)` Constructor for the HttpURLConnection.

Method Summary

Methods
Modifier and Type	Method and Description
`abstract void`	`disconnect()` Indicates that other requests to the server are unlikely in the near future.
`InputStream`	`getErrorStream()` Returns the error stream if the connection failed but the server sent useful data nonetheless.
`static boolean`	`getFollowRedirects()` Returns a `boolean` indicating whether or not HTTP redirects (3xx) should be automatically followed.
`String`	`getHeaderField(int n)` Returns the value for the `n`^th header field.
`long`	`getHeaderFieldDate(String name, long Default)` Returns the value of the named field parsed as date.
`String`	`getHeaderFieldKey(int n)` Returns the key for the `n`^th header field.
`boolean`	`getInstanceFollowRedirects()` Returns the value of this `HttpURLConnection`'s `instanceFollowRedirects` field.
`Permission`	`getPermission()` Returns a permission object representing the permission necessary to make the connection represented by this object.
`String`	`getRequestMethod()` Get the request method.
`int`	`getResponseCode()` Gets the status code from an HTTP response message.
`String`	`getResponseMessage()` Gets the HTTP response message, if any, returned along with the response code from a server.
`static void`	`setFollowRedirects(boolean set)` Sets whether HTTP redirects (requests with response code 3xx) should be automatically followed by this class.
`void`	`setInstanceFollowRedirects(boolean followRedirects)` Sets whether HTTP redirects (requests with response code 3xx) should be automatically followed by this `HttpURLConnection` instance.
`void`	`setRequestMethod(String method)` Set the method for the URL request, one of: GET POST HEAD OPTIONS PUT DELETE TRACE are legal, subject to protocol restrictions.
`abstract boolean`	`usingProxy()` Indicates if the connection is going through a proxy.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - method
```
protected String method
```
    The HTTP method (GET,POST,PUT,etc.).
  - responseCode
```
protected int responseCode
```
    An int representing the three digit HTTP Status-Code.
    - 1xx: Informational
    - 2xx: Success
    - 3xx: Redirection
    - 4xx: Client Error
    - 5xx: Server Error
  - responseMessage
```
protected String responseMessage
```
    The HTTP response message.
  - 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.
    
    See Also:
    setInstanceFollowRedirects(boolean), getInstanceFollowRedirects(), setFollowRedirects(boolean)
  - HTTP_OK
```
public static final int HTTP_OK
```
    HTTP Status-Code 200: OK.
    
    See Also:
    Constant Field Values
  - HTTP_CREATED
```
public static final int HTTP_CREATED
```
    HTTP Status-Code 201: Created.
    
    See Also:
    Constant Field Values
  - HTTP_ACCEPTED
```
public static final int HTTP_ACCEPTED
```
    HTTP Status-Code 202: Accepted.
    
    See Also:
    Constant Field Values
  - HTTP_NOT_AUTHORITATIVE
```
public static final int HTTP_NOT_AUTHORITATIVE
```
    HTTP Status-Code 203: Non-Authoritative Information.
    
    See Also:
    Constant Field Values
  - HTTP_NO_CONTENT
```
public static final int HTTP_NO_CONTENT
```
    HTTP Status-Code 204: No Content.
    
    See Also:
    Constant Field Values
  - HTTP_RESET
```
public static final int HTTP_RESET
```
    HTTP Status-Code 205: Reset Content.
    
    See Also:
    Constant Field Values
  - HTTP_PARTIAL
```
public static final int HTTP_PARTIAL
```
    HTTP Status-Code 206: Partial Content.
    
    See Also:
    Constant Field Values
  - HTTP_MULT_CHOICE
```
public static final int HTTP_MULT_CHOICE
```
    HTTP Status-Code 300: Multiple Choices.
    
    See Also:
    Constant Field Values
  - HTTP_MOVED_PERM
```
public static final int HTTP_MOVED_PERM
```
    HTTP Status-Code 301: Moved Permanently.
    
    See Also:
    Constant Field Values
  - HTTP_MOVED_TEMP
```
public static final int HTTP_MOVED_TEMP
```
    HTTP Status-Code 302: Temporary Redirect.
    
    See Also:
    Constant Field Values
  - HTTP_SEE_OTHER
```
public static final int HTTP_SEE_OTHER
```
    HTTP Status-Code 303: See Other.
    
    See Also:
    Constant Field Values
  - HTTP_NOT_MODIFIED
```
public static final int HTTP_NOT_MODIFIED
```
    HTTP Status-Code 304: Not Modified.
    
    See Also:
    Constant Field Values
  - HTTP_USE_PROXY
```
public static final int HTTP_USE_PROXY
```
    HTTP Status-Code 305: Use Proxy.
    
    See Also:
    Constant Field Values
  - HTTP_BAD_REQUEST
```
public static final int HTTP_BAD_REQUEST
```
    HTTP Status-Code 400: Bad Request.
    
    See Also:
    Constant Field Values
  - HTTP_UNAUTHORIZED
```
public static final int HTTP_UNAUTHORIZED
```
    HTTP Status-Code 401: Unauthorized.
    
    See Also:
    Constant Field Values
  - HTTP_PAYMENT_REQUIRED
```
public static final int HTTP_PAYMENT_REQUIRED
```
    HTTP Status-Code 402: Payment Required.
    
    See Also:
    Constant Field Values
  - HTTP_FORBIDDEN
```
public static final int HTTP_FORBIDDEN
```
    HTTP Status-Code 403: Forbidden.
    
    See Also:
    Constant Field Values
  - HTTP_NOT_FOUND
```
public static final int HTTP_NOT_FOUND
```
    HTTP Status-Code 404: Not Found.
    
    See Also:
    Constant Field Values
  - HTTP_BAD_METHOD
```
public static final int HTTP_BAD_METHOD
```
    HTTP Status-Code 405: Method Not Allowed.
    
    See Also:
    Constant Field Values
  - HTTP_NOT_ACCEPTABLE
```
public static final int HTTP_NOT_ACCEPTABLE
```
    HTTP Status-Code 406: Not Acceptable.
    
    See Also:
    Constant Field Values
  - HTTP_PROXY_AUTH
```
public static final int HTTP_PROXY_AUTH
```
    HTTP Status-Code 407: Proxy Authentication Required.
    
    See Also:
    Constant Field Values
  - HTTP_CLIENT_TIMEOUT
```
public static final int HTTP_CLIENT_TIMEOUT
```
    HTTP Status-Code 408: Request Time-Out.
    
    See Also:
    Constant Field Values
  - HTTP_CONFLICT
```
public static final int HTTP_CONFLICT
```
    HTTP Status-Code 409: Conflict.
    
    See Also:
    Constant Field Values
  - HTTP_GONE
```
public static final int HTTP_GONE
```
    HTTP Status-Code 410: Gone.
    
    See Also:
    Constant Field Values
  - HTTP_LENGTH_REQUIRED
```
public static final int HTTP_LENGTH_REQUIRED
```
    HTTP Status-Code 411: Length Required.
    
    See Also:
    Constant Field Values
  - HTTP_PRECON_FAILED
```
public static final int HTTP_PRECON_FAILED
```
    HTTP Status-Code 412: Precondition Failed.
    
    See Also:
    Constant Field Values
  - HTTP_ENTITY_TOO_LARGE
```
public static final int HTTP_ENTITY_TOO_LARGE
```
    HTTP Status-Code 413: Request Entity Too Large.
    
    See Also:
    Constant Field Values
  - HTTP_REQ_TOO_LONG
```
public static final int HTTP_REQ_TOO_LONG
```
    HTTP Status-Code 414: Request-URI Too Large.
    
    See Also:
    Constant Field Values
  - HTTP_UNSUPPORTED_TYPE
```
public static final int HTTP_UNSUPPORTED_TYPE
```
    HTTP Status-Code 415: Unsupported Media Type.
    
    See Also:
    Constant Field Values
  - HTTP_INTERNAL_ERROR
```
public static final int HTTP_INTERNAL_ERROR
```
    HTTP Status-Code 500: Internal Server Error.
    
    See Also:
    Constant Field Values
  - HTTP_NOT_IMPLEMENTED
```
public static final int HTTP_NOT_IMPLEMENTED
```
    HTTP Status-Code 501: Not Implemented.
    
    See Also:
    Constant Field Values
  - HTTP_BAD_GATEWAY
```
public static final int HTTP_BAD_GATEWAY
```
    HTTP Status-Code 502: Bad Gateway.
    
    See Also:
    Constant Field Values
  - HTTP_UNAVAILABLE
```
public static final int HTTP_UNAVAILABLE
```
    HTTP Status-Code 503: Service Unavailable.
    
    See Also:
    Constant Field Values
  - HTTP_GATEWAY_TIMEOUT
```
public static final int HTTP_GATEWAY_TIMEOUT
```
    HTTP Status-Code 504: Gateway Timeout.
    
    See Also:
    Constant Field Values
  - HTTP_VERSION
```
public static final int HTTP_VERSION
```
    HTTP Status-Code 505: HTTP Version Not Supported.
    
    See Also:
    Constant Field Values
- Constructor Detail
  - HttpURLConnection
```
protected HttpURLConnection(URL u)
```
    Constructor for the HttpURLConnection.
    
    Parameters:
    u - the URL
- Method Detail
  - getHeaderFieldKey
```
public String getHeaderFieldKey(int n)
```
    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.
    
    Overrides:
    
    getHeaderFieldKey in class URLConnection
    
    Parameters:
    n - an index, where n >=0.
    
    Returns:
    the key for the n^th header field, or null if the key does not exist.
  - getHeaderField
```
public String getHeaderField(int n)
```
    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.
    
    Overrides:
    
    getHeaderField in class URLConnection
    
    Parameters:
    n - an index, where n>=0.
    
    Returns:
    the value of the n^th header field, or null if the value does not exist.
    See Also:
    getHeaderFieldKey(int)
  - 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.
    
    Parameters:
    set - a boolean indicating whether or not to follow HTTP redirects.
    
    Throws:
    
    SecurityException - if a security manager exists and its checkSetFactory method doesn't allow the operation.
    See Also:
    SecurityManager.checkSetFactory(), getFollowRedirects()
  - getFollowRedirects
```
public static boolean getFollowRedirects()
```
    Returns a boolean indicating whether or not HTTP redirects (3xx) should be automatically followed.
    
    Returns:
    true if HTTP redirects should be automatically followed, false if not.
    See Also:
    setFollowRedirects(boolean)
  - 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.
    
    Parameters:
    followRedirects - a boolean indicating whether or not to follow HTTP redirects.
    See Also:
    instanceFollowRedirects, getInstanceFollowRedirects()
  - getInstanceFollowRedirects
```
public boolean getInstanceFollowRedirects()
```
    Returns the value of this HttpURLConnection's instanceFollowRedirects field.
    
    Returns:
    the value of this HttpURLConnection's instanceFollowRedirects field.
    See Also:
    instanceFollowRedirects, setInstanceFollowRedirects(boolean)
  - setRequestMethod
```
public void setRequestMethod(String method)
                      throws ProtocolException
```
    Set the method for the URL request, one of:
    - GET
    - POST
    - HEAD
    - OPTIONS
    - PUT
    - DELETE
    - TRACE
    are legal, subject to protocol restrictions. The default method is GET.
    Parameters:
    method - the HTTP method
    
    Throws:
    
    ProtocolException - if the method cannot be reset or if the requested method isn't valid for HTTP.
    See Also:
    getRequestMethod()
  - getRequestMethod
```
public String getRequestMethod()
```
    Get the request method.
    
    Returns:
    the HTTP request method
    See Also:
    setRequestMethod(java.lang.String)
  - getResponseCode
```
public int getResponseCode()
                    throws IOException
```
    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).
    Returns:
    the HTTP Status-Code, or -1
    
    Throws:
    
    IOException - if an error occurred connecting to the server.
  - 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).
    Returns:
    the HTTP response message, or null
    
    Throws:
    
    IOException - if an error occurred connecting to the server.
  - getHeaderFieldDate
```
public long getHeaderFieldDate(String name,
                      long Default)
```
    Description copied from class: URLConnection
    
    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.
    
    Overrides:
    
    getHeaderFieldDate in class URLConnection
    
    Parameters:
    name - the name of the header field.
    Default - a default value.
    
    Returns:
    the value of the field, parsed as a date. The value of the Default argument is returned if the field is missing or malformed.
  - 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()
```
    Indicates if the connection is going through a proxy.
    
    Returns:
    a boolean indicating if the connection is using a proxy.
  - getPermission
```
public Permission getPermission()
                         throws IOException
```
    Description copied from class: URLConnection
    
    Returns a permission object representing the permission necessary to make the connection represented by this object. This method returns null if no permission is required to make the connection. By default, this method returns java.security.AllPermission. Subclasses should override this method and return the permission that best represents the permission required to make a a connection to the URL. For example, a URLConnection representing a file: URL would return a java.io.FilePermission object.
    The permission returned may dependent upon the state of the connection. For example, the permission before connecting may be different from that after connecting. For example, an HTTP sever, say foo.com, may redirect the connection to a different host, say bar.com. Before connecting the permission returned by the connection will represent the permission needed to connect to foo.com, while the permission returned after connecting will be to bar.com.
    Permissions are generally used for two purposes: to protect caches of objects obtained through URLConnections, and to check the right of a recipient to learn about a particular URL. In the first case, the permission should be obtained after the object has been obtained. For example, in an HTTP connection, this will represent the permission to connect to the host from which the data was ultimately fetched. In the second case, the permission should be obtained and tested before connecting.
    
    Overrides:
    
    getPermission in class URLConnection
    
    Returns:
    the permission object representing the permission necessary to make the connection represented by this URLConnection.
    
    Throws:
    
    IOException - if the computation of the permission requires network or file I/O and an exception occurs while computing it.
  - getErrorStream
```
public InputStream 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.
    
    Returns:
    an error stream if any, null if there have been no errors, the connection is not connected or the server sent no useful data.

Class HttpURLConnection

Field Summary

Fields inherited from class java.net.URLConnection

Constructor Summary

Method Summary

Methods inherited from class java.net.URLConnection

Methods inherited from class java.lang.Object

Field Detail

method

responseCode

responseMessage

instanceFollowRedirects

HTTP_OK

HTTP_CREATED

HTTP_ACCEPTED

HTTP_NOT_AUTHORITATIVE

HTTP_NO_CONTENT

HTTP_RESET

HTTP_PARTIAL

HTTP_MULT_CHOICE

HTTP_MOVED_PERM

HTTP_MOVED_TEMP

HTTP_SEE_OTHER

HTTP_NOT_MODIFIED

HTTP_USE_PROXY

HTTP_BAD_REQUEST

HTTP_UNAUTHORIZED

HTTP_PAYMENT_REQUIRED

HTTP_FORBIDDEN

HTTP_NOT_FOUND

HTTP_BAD_METHOD

HTTP_NOT_ACCEPTABLE

HTTP_PROXY_AUTH

HTTP_CLIENT_TIMEOUT

HTTP_CONFLICT

HTTP_GONE

HTTP_LENGTH_REQUIRED

HTTP_PRECON_FAILED

HTTP_ENTITY_TOO_LARGE

HTTP_REQ_TOO_LONG

HTTP_UNSUPPORTED_TYPE

HTTP_INTERNAL_ERROR

HTTP_NOT_IMPLEMENTED

HTTP_BAD_GATEWAY

HTTP_UNAVAILABLE

HTTP_GATEWAY_TIMEOUT

HTTP_VERSION

Constructor Detail

HttpURLConnection

Method Detail

getHeaderFieldKey

getHeaderField

setFollowRedirects

getFollowRedirects

setInstanceFollowRedirects

getInstanceFollowRedirects

setRequestMethod

getRequestMethod

getResponseCode

getResponseMessage

getHeaderFieldDate

disconnect

usingProxy

getPermission

getErrorStream