The difference between request.getparameter () and Request.getparametervalues ()

Let's see what the API says.

Java.lang.String getparameter (String name): Returns The value of a request parameter as astring, or null if the parameter does not exist.

Returns the value of a string request parameter that returns NULL if the request parameter does not exist

Java.lang.string[] Getparametervalus (String name): Returns An array of String objects containing all of the values the GIV En request parameter has, ornull if the parameter does not exist.

Returns an array of type string containing all the values of the request parameter, or NULL if the request parameter does not exist

So in a checkbox or a select space, the value of the request parameter may be many, and you can use the Getparametervalus (String name) method to get an array of all the values. The array is then traversed to obtain each parameter.