This paper proposes a new technique for automated support of selection and customization of application frameworks, by using labeled transition systems (LTSs) together with metrics technique. We model the behavior of the frameworks and the system behavior specified in the requirements specification by using two LTSs respectively. We attach some measures to the LTS of the framework, such as the number of the hot spots to be filled. These measures are used to estimate developer's efforts in filling the hot spots for each implementation. The result of estimating the efforts guides the developers to select the implementation, and the structure of the application-specific codes to be filled in can be automatically generated from the selected implementation. Furthermore we discuss case studies in the area of Web application, where Struts and Turbine can be used.