Package
java.applet:Provides the classes necessary to create an applet and the classes an applet uses to communicate with its applet context.
Interfaces
AppletContext:This interface corresponds to an applet's environment: the document containing the applet and the other applets in the same document.
The methods in this interface can be used by an applet to obtain information about its environment.
AppletStub:When an applet is first created, an applet stub is attached to it using the applet's setStub method. This stub serves as the interface between the applet and the browser environment or applet viewer environment in which the application is running.
AudioClip:The AudioClip interface is a simple abstraction for playing a sound clip. Multiple AudioClip items can be playing at the same time, and the resulting sound is mixed together to produce a composite
Classes
Applet:An applet is a small program that is intended not to be run on its own, but rather to be embedded inside another application.
The Applet class must be the superclass of any applet that is to be embedded in a Web page or viewed by the Java Applet Viewer. The Applet class provides a standard interface between applets and their environment.
不测不知道，一测吓一跳! 做完程序后一定要耐下心来做做测试。
总结一下上个任务测试后出现的错误：
1.对需求文档理解不够，导致对于输出变量时的判断条件书写错误
2.开发或测试后的代码记得删掉，减少表的查询
3.SQL查询在两者之间用between，最好用A>B，A<C来表示A在B和C之间