With the rapid development of mobile computing techniques, mobile users can share the computing capability and resource of their mobile devices and other surrounding devices as services. However, privately-owned, resource-constrained and portable mobile devices pose challenge to the publishing and composition processes of such personal services. Specifically, such personal services may intrude the privacy of the providers, consume the constrained computing resource, and suffer failures caused by the changing network environment. To address these problems, this paper proposes a new approach for personal service publishing and mixed service composition in mobile computing environment. This approach introduces the concept of service willingness during personal service publishing, and takes into account both service willingness and service utility during service selection. Further, it presents a resource-aware heartbeat mechanism to periodically update the status of devices and services for service selection, which can also help settling service failures caused by the changing network environment. Based on JADE and OSGi, it offers an implementation framework for the proposed approach. Finally, a case study is provided to show the effectiveness of the proposed implementation framework and the rationales for considering service willingness in mobile computing environment.