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针对复杂的传统Java智能卡指令解析问题,结合Applet的部署特点,提出了指令预解析的概念;给出了转换后的Applet文件(CAP,Converted Applet file)中导入组件、常数池和导出组件的预解析优化存储结构及包注册表结构,使用定长存储结构替代原有的变长存储结构以加快查找过程,引入了导出组件辅助索引表以加快外包类的解析过程;设计了基于优化后组件的静态域、静态方法和类访问字节码指令的快速解析流程,将解析算法的时间复杂度降为常数阶;在Applet下载过程中通过预解析来生成优化后的组件存储结构,在执行过程中依据快速解析流程来完成静态域、静态方法和类对象的快速访问,从而缩短了Applet运行时的解析时间.测试结果表明,在不改变标准Applet下载、运行流程的情况下,该方法有效地减少了卡内存储器的访问次数,缩短了解析算法的执行时间,提高了Applet执行的整体性能.
Aiming at the problem of complex traditional Java smart card instructions parsing, combined with the deployment characteristics of Applets, the concept of instruction pre-parsing is proposed. Pre-parsing is given in the Converted Applet file (CAP) Parsing and optimizing the storage structure and the package registry structure, using the fixed-length storage structure to replace the original variable-length storage structure to speed up the search process, and introducing the auxiliary component index table to speed up the outsourcing class parsing process; Static domain, static method and class access bytecode instruction fast resolution process, the analytical complexity of the algorithm is reduced to a constant order; in the Applet download process through pre-analysis to generate an optimized component storage structure, in the implementation process Based on the fast parsing process, the static domain, static methods and quick access to the class object are completed, which shortens the parsing time of the applet runtime.The test results show that the method can effectively reduce the time without changing the standard applet download and running process The number of visits to the card memory, shorten the analysis of the implementation of the algorithm, improve the implementation of the entire Applet Body performance.