Java编程语言基础（外文文献翻译）.docVIP

JavaTM Programming Language Basics Like applications, applets are created from classes. However, applets do not have a main method as an entry point, but instead, have several methods to control specific aspects of applet execution. This lesson converts an application from Lesson 2 to an applet and describes the structure and elements of an applet. 1、Application to Applet 2、Run the Applet 3、Applet Structure and Elements 4、Packages 5、More Information 1、Application to Applet The following code is the applet equivalent to the LessonTwoB application from Lesson 2. The figure below shows how the running applet looks. The structure and elements of the applet code are discussed after the section on how to run the applet just below. import java.applet.Applet; import java.awt.Graphics; import java.awt.Color; public class SimpleApplet extends Applet{ String text = Im a simple applet; public void init() { text = Im a simple applet; setBackground(Color.cyan); } public void start() { System.out.println(starting...); } public void stop() { System.out.println(stopping...); } public void destroy() { System.out.println(preparing to unload...); } public void paint(Graphics g){ System.out.println(Paint); g.setColor(Color.blue); g.drawRect(0, 0, getSize().width -1, getSize().height -1); g.setColor(Color.red); g.drawString(text, 15, 25); } } The SimpleApplet class is declared public so the program that runs the applet (a browser or appletviewer), which is not local to the program can access it. 2、Run the Applet To see the applet in action, you need an HTML file with the Applet tag as follows: HTML BODY APPLET CODE=SimpleApplet.class WIDTH=200 HEIGHT=100 /APPLET /BODY /HTML The easiest way to run the applet is with appletviewer shown below where simpleApplet.html is a file that contains the above HTML code: appletviewer simpleApplet.html Note: To r