jar 文件和小程序是两种不同的东西.您应该考虑阅读有关它们的一些基础知识.小程序是从网页启动的，没有 main 方法.它有自己的方法循环.你不能通过双击 jar 文件来运行它，但你必须从网页上调用它.

A jar file and an applet are two different things. You should consider reading some basics about them. A applet is launched form a web page and has no main method. It has its own cycle of methods. You cant run it by double clicking the jar file but you have to call it from a web page.

考虑阅读:

1. Java 小程序

JAR 格式

Java Web 视图(这可能很有趣)