fix string 2 bugs
fix string 2 bugs

whuthj/zpublic,wohaaitinciu/zpublic,whuthj/zpublic,zpublic/zpublic,wohaaitinciu/zpublic,jasonzhong/zpublic,zpublic/zpublic,AlexXChina/zpublic,jasonzhong/zpublic,AlexXChina/zpublic,whuthj/zpublic