在命令提示符下编译时为什么出现这个错误?
E:\j2sdk1.4.2\bin>javac MyFirstJavaApplet.java
MyFirstJavaApplet.java:7:cannot resolve symbol
symbol :method drawingstring (java.lang.String,int,int)
location:class java.awt.Graphics
g.drawingString("This is my first java Applet!",15,20);
^
1 error
请按任意键继续. . .源程序如下:
import java.applet.Applet;
import java.awt.Graphics;
public class MyFirstJavaApplet extends Applet
{
public void paint(Graphics g)
{
g.drawingString("This is my first java program!",15,20);
}
}
换成java Application出现这个错误:
E:\j2sdk1.4.2\bin>javac MyFirstJavaProgram.javaE:\j2sdk1.4.2\bin>java MyFirstJavaProgram
Exception in thread "main" java.lang.NoClassDefFoundError: MyFirstJavaProgramjava Application源程序如下:
public class MyFirstJavaProgram
{
public static void main(String arg[])
{
System.out.println("This is my first java program!");
}
}
E:\j2sdk1.4.2\bin>javac MyFirstJavaApplet.java
MyFirstJavaApplet.java:7:cannot resolve symbol
symbol :method drawingstring (java.lang.String,int,int)
location:class java.awt.Graphics
g.drawingString("This is my first java Applet!",15,20);
^
1 error
请按任意键继续. . .源程序如下:
import java.applet.Applet;
import java.awt.Graphics;
public class MyFirstJavaApplet extends Applet
{
public void paint(Graphics g)
{
g.drawingString("This is my first java program!",15,20);
}
}
换成java Application出现这个错误:
E:\j2sdk1.4.2\bin>javac MyFirstJavaProgram.javaE:\j2sdk1.4.2\bin>java MyFirstJavaProgram
Exception in thread "main" java.lang.NoClassDefFoundError: MyFirstJavaProgramjava Application源程序如下:
public class MyFirstJavaProgram
{
public static void main(String arg[])
{
System.out.println("This is my first java program!");
}
}
改:g.drawString("This is my first java Applet!",15,20);第二出错的原因是:环境变量没设定!
解决如下:
1、path中加入:E:\j2sdk1.4.2\bin; // :) 你的java的安装目录
2、classpath中加入:".;" // 说明:在classpath最前面加入[点 + 分号] 没有双引号
3、切换到MyFirstJavaProgram.java 文件的所在地. 比如:f:\test\ 下 f:\test>
4、运行f:\test>javac MyFirstJavaProgram.javaf:\test>java MyFirstJavaProgram.java