如何在java中编译和执行包文件 [英] How to compile and execute a package file in java

问题描述

我正在从'Java2：Schield的完整参考资料'学习Java。我正在使用带有命令提示符（JDK）的Windows 7系统来编译和执行Java程序。我正在尝试编译一个包含程序包的程序，如下面的代码所示：

  import  java。 AWT *。 
  package  MyPack; 
  class 余额
 {
 字符串名称; 
  double  bal; 
余额（字符串 n， double  b）
 {
 name = n; 
 bal = b; 
} 
  void  show（）
 {
  if （bal< 0）
 {
 System.out.print（   - > ）; 
 System.out.println（name +  ：$ + bal）; 
} 
} 
} 
  class 帐户
 {
  public   static   void  main（字符串 args []）
 {
余额当前[] = 新余额[ 3 ]; 
当前[ 0 ] =  new 余额（   KJ Fielding， 123 。 23 ）; 
当前[ 1 ] =  new 余额（  将告诉， 157 。 02 ）; 
当前[ 2 ] =  new 余额（   Tom Jackson， -   12 。 33 ）; 
  for （ int  i =  0 ; i<  3 ; i ++）current [i] .show（）; 
} 
} 

当我执行

>C： \Program Files\Java\jdk1.7.0_25\bin\javacAccount.java（来自MyPack文件夹

或

> C：\Program Files\Java\jdk1.7.0_25\bin\javacMyPack / Account.java（在MyPack文件夹之外），



我收到以下错误：



Account.java:2：错误：类，接口或枚举预期包MyPack;



或



MyPack \Account.java：2：错误：类，接口或枚举预期包MyPack;< br $> b $ b

请让我知道如何编译然后执行这样的程序？



什么我试过了：



我试过从MyPack文件夹里面以及在我之外编译程序，如上面的查询中所述。

解决方案

+ bal）;
}
}
}
class 帐户
{
public static void main（字符串 args []）
{
余额当前[] = 新余额[ 3 ];
当前[ 0 ] = new 余额（ KJ Fielding， 123 。 23 ）;
当前[ 1 ] = new 余额（ 将告诉， 157 。 02 ）;
当前[ 2 ] = new 余额（ Tom Jackson， - 12 。 33 ）;
for （ int i = 0 ; i< 3 ; i ++）current [i] .show（）;
}
}

当我执行

>C： \Program Files\Java\jdk1.7.0_25\bin\javacAccount.java（来自MyPack文件夹

或

> C：\Program Files\Java\jdk1.7.0_25\bin\javacMyPack / Account.java（在MyPack文件夹之外），



我收到以下错误：



Account.java:2：错误：类，接口或枚举预期包MyPack;



或



MyPack \Account.java：2：错误：类，接口或枚举预期包MyPack;< br $> b $ b

请让我知道如何编译然后执行这样的程序？



什么我试过了：



我已经尝试从MyPack文件夹中以及在我之外编译程序，如上面的查询中所述。

包州议员t应该在 import 之前。请参阅 Java™教程 [ ^ ]。

I am learning Java from ‘Java2: The Complete Reference by Schield". I am using a Windows 7 system with command prompt (JDK) to compile and execute Java programs. I am trying to compile a program having a package as seen in the code below:

import java.awt.*;
package MyPack;
class Balance
{
	String name;
	double bal;
	Balance(String n, double b)
	{
		name = n;
		bal = b;
	}
	void show()
	{
		if(bal<0)
		{
			System.out.print("--> ");
			System.out.println(name + ": $" + bal);
		}	
	}
}
class Account
{
	public static void main(String args[])
	{
		Balance current[] = new Balance[3];
		current[0] = new Balance("K. J. Fielding", 123.23);
		current[1] = new Balance("Will Tell", 157.02);
		current[2] = new Balance("Tom Jackson", -12.33);
		for(int i = 0; i < 3; i++) current[i].show();
	}
}

When I execute either
>"C:\Program Files\Java\jdk1.7.0_25\bin\javac" Account.java" (from within the MyPack folder"
or
>"C:\Program Files\Java\jdk1.7.0_25\bin\javac" MyPack/Account.java (outside the MyPack folder),

I receive the following error:

" Account.java:2: error: class, interface, or enum expected package MyPack;"

Or

"MyPack\Account.java:2: error: class, interface, or enum expected package MyPack;"

Please let me know how I can compile and then execute such a program?

What I have tried:

I have tried compiling the program from inside the MyPack folder as well as outside it as explained in my query above.

解决方案

" + bal); } } } class Account { public static void main(String args[]) { Balance current[] = new Balance[3]; current[0] = new Balance("K. J. Fielding", 123.23); current[1] = new Balance("Will Tell", 157.02); current[2] = new Balance("Tom Jackson", -12.33); for(int i = 0; i < 3; i++) current[i].show(); } }

When I execute either
>"C:\Program Files\Java\jdk1.7.0_25\bin\javac" Account.java" (from within the MyPack folder"
or
>"C:\Program Files\Java\jdk1.7.0_25\bin\javac" MyPack/Account.java (outside the MyPack folder),

I receive the following error:

" Account.java:2: error: class, interface, or enum expected package MyPack;"

Or

"MyPack\Account.java:2: error: class, interface, or enum expected package MyPack;"

Please let me know how I can compile and then execute such a program?

What I have tried:

I have tried compiling the program from inside the MyPack folder as well as outside it as explained in my query above.

The package statement should come before the import. See The Java™ Tutorials[^].

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