getAttribute
public java.lang.Object getAttribute(java.lang.String name)
Returns the value of the named attribute as an 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.*.
Parameters:
name - a String specifying the name of the attribute
Returns:
an Object containing the value of the attribute, or null if the attribute does not exist
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getParameter
public java.lang.String getParameter(java.lang.String name)
Returns the value of a request parameter as a 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.
Parameters:
name - a String specifying the name of the parameter
Returns:
a String representing the single value of the parameter
See Also:
getParameterValues(java.lang.String)