system.debug(System.Encodingutil.urlEncode('你好', 'gb2312'));

output  "%C4%E3%BA%C3"

system.debug(System.Encodingutil.urlEncode('你好', 'utf-8'));

output  "%E4%BD%A0%E5%A5%BD"

Page:

<apex:inputTextarea value="{!fchrMsg}" id="fchrMsg"/>

class:

    public string fchrMsg{
        get{
            if(fchrMsg == null){
                string fchrTmpMsg = ApexPages.currentPage().getParameters().get('msg');
                if(fchrTmpMsg != null)
                    fchrMsg = System.Encodingutil.urlDecode(fchrTmpMsg, 'gb2312');
                else
                    fchrMsg = '';
            }
            return fchrMsg;
        }
        set{
            fchrMsg = value;
        }
    }

I want to receive parameter by the url "mypage?msg=%C4%E3%BA%C3"

but i get a null value

Who can help me!