Question

此代码在打包在jar文件中时无法运行，但在Eclipse中构建时运行正常。

/* Calculator */
import java.awt.*;
import java.awt.event.*;
import java.lang.Math;
import javax.swing.*;
class Calculator extends Frame implements ActionListener  {
    Font font1 = new Font( "Times New Roman",  Font.PLAIN,  20 );
    JLabel  Label1,  Label2,  Label3;
    JTextField  txt1,  txt2,  txt3;
    // 4 JButton
    JButton  Add = new JButton( "  +  " );
    JButton  Sub = new JButton( "  -  " );
    JButton  Mul = new JButton( "  x  " );
    JButton  Div = new JButton( "  /  " );
    JButton  Power = new JButton( "  ^  " );
    JButton  Sin = new JButton( "  Sin  " );
    JButton  Cos = new JButton( "  Cos  " );
    JButton  Tan = new JButton( "  Tan  " );
    JButton  Arcsin = new JButton( "  Arcsin  " );
    JButton  Arccos = new JButton( "  Arccos  " );
    JButton  Arctan = new JButton( "  Arctan  " );
    JButton  Factorial = new JButton( "  Factorial  " );
    JButton  Combinatory = new JButton( "  Combinatory  " );

    // 2 Panels will contain components
    Panel  p1 = new Panel( new GridLayout( 3, 2 ) );
    Panel  p2 = new Panel( new GridLayout( 4, 4 ) );

/* Calculator( )  */
    Calculator( )  {
        super ( "Calculator" );
        Label1 = new JLabel ( "First number: ", Label.LEFT );
        Label2 = new JLabel ( "Second number: ", Label.LEFT );
        Label3 = new JLabel ( "Result: ", Label.LEFT );
        txt1 = new JTextField( );  txt2 = new JTextField( );   txt3 = new JTextField( ); 
        txt1.setFont( font1 );  txt2.setFont( font1 );   txt3.setFont( font1 );
        txt1.setPreferredSize( new Dimension ( 100, 20 ) );
        txt2.setPreferredSize( new Dimension ( 100, 20 ) );
        txt3.setPreferredSize( new Dimension ( 100, 20 ) );

        Label1.setFont( font1 );  Label2.setFont( font1 );  
        Label3.setFont( font1 );  
        // Adding lables and textbox to panel p1
        p1.setMaximumSize( new Dimension( 3*100,  2*200 ) );
        p2.setMaximumSize( new Dimension( 4*100,  4*100 ) );
        p1.add( Label1 );  p1.add( txt1 );
        p1.add( Label2 );  p1.add( txt2 );
        p1.add( Label3 );  p1.add( txt3 );
        // Adding 4 JButtons to panel p2
        p2.add( Add );  p2.add( Sub );  p2.add( Mul );  p2.add( Div );
        p2.add( Power );  p2.add( Factorial );  p2.add( Combinatory ); 
        p2.add( Sin );  p2.add( Cos );  p2.add( Tan );  
        p2.add( Arcsin );  p2.add( Arccos );  p2.add( Arctan );  

        // set layout of this frame is FlowLayout
        this.setLayout( new FlowLayout( ) );
        // Adding 2 panels to this frame
        this.add( p1 );  this.add( p2 );
        Add.addActionListener( this );  Sub.addActionListener( this );
        Mul.addActionListener( this );  Div.addActionListener( this );
        Power.addActionListener( this );  Factorial.addActionListener( this );
        Sin.addActionListener( this );  Cos.addActionListener( this );
        Tan.addActionListener( this );  Arcsin.addActionListener( this );
        Arccos.addActionListener( this );  Arctan.addActionListener( this );
        Combinatory.addActionListener( this );

      // Managing window closing event
        addWindowListener ( new WindowAdapter( )  {
            public void windowClosing( WindowEvent event )  { System.exit( 0 ); }
        } );  
    /* Add close JButton or we can use:         
        setDefaultCloseOperation ( JFrame.DISPOSE_ON_CLOSE ); in constructor Calculator( )  */
    }
    public long Factorial ( long n )  {
        int i, n1;  n1 = 1;
        for ( i = 1; i <= n; i++ )
            n1 = n1*i;
        return n1; 
    }


/* public void actionPerformed ( ActionEvent e ) */
    public void actionPerformed ( ActionEvent e ) {
        /* Method will be automatic called when ActionListener receive action
            from the listened objects */
        double k3;  double PI = 3.141592654;
        //  Convert inputted content into number data
        double k1 = Double.parseDouble ( txt1.getText( ) );  
        double k2 = Double.parseDouble ( txt2.getText( ) );  
        String s1, s2, s3, s4;  s1 = txt1.getText( );  s2 = txt2.getText( );  
        if ( e.getSource( ) == Add )  {  
            // If event source is JButton Add
            k3 = k1 + k2;  s3 = Double.toString( k3 );
            s4 = s1 + " + " + s2 + " = " + s3;
            txt3.setText( s4  ); 
            /* txt3, s4 = Result */
        } 
        if ( e.getSource( ) == Sub )  {  
            k3 = k1 - k2;  s3 = Double.toString( k3 );
            s4 = s1 + " - " + s2 + " = " + s3;
            txt3.setText( s4  ); 
        } 
        if ( e.getSource(   ) == Mul )  {  
            k3 = k1 * k2;  s3 = Double.toString( k3 );
            s4 = s1 + " * " + s2 + " = " + s3;
            txt3.setText( s4  ); 
        } 
        if ( e.getSource( ) == Div )  {  
            k3 = k1 / k2;  s3 = Double.toString( k3 );
            s4 = s1 + " / " + s2 + " = " + s3;
            txt3.setText( s4  ); 
        } 
        if ( e.getSource( ) == Power )  {  
            k3 = Math.exp( Math.log( k1 ) * k2 );  s3 = Double.toString( k3 );
            s4 = s1 + " ^ " + s2 + " = " + s3;
            txt3.setText( s4  ); 
        } 
        if ( e.getSource( ) == Factorial )  {
            long  n, n1;  n = ( long ) k1;  
            n1 = Factorial( n );
            s3 = Long.toString( n1 );  s1 = Long.toString( n );
            s4 = s1 + "! = " + s3;
            txt3.setText( s4  ); 
        } 
        if ( e.getSource( ) == Sin )  {
            k1 = k1*PI/180;  
            k3 = Math.sin( k1 );  s3 = Double.toString( k3 );
            s4 = "Sin( " + s1 + " ) = " + s3;
            txt3.setText( s4  );  
        } 
        if ( e.getSource( ) == Cos )  { 
            k1 = k1*PI/180;   
            k3 = Math.cos( k1 );  s3 = Double.toString( k3 );
            s4 = "Cos( " + s1 + " ) = " + s3;
            txt3.setText( s4  );  
        } 
        if ( e.getSource( ) == Tan )  { 
            k1 = k1*PI/180;   
            k3 = Math.tan( k1 );  s3 = Double.toString( k3 );
            s4 = "Tan( " + s1 + " ) = " + s3;
            txt3.setText( s4  );  
        } 
        if ( e.getSource( ) == Arcsin )  { 
            k3 = Math.asin( k1 );  k3 = k3*180/PI; 
            s3 = Double.toString( k3 );
            s4 = "Arcsin( " + s1 + " ) = " + s3;
            txt3.setText( s4  );  
        } 
        if ( e.getSource( ) == Arccos )  {  
            k3 = Math.acos( k1 );  k3 = k3*180/PI; 
            s3 = Double.toString( k3 );
            s4 = "Arccos( " + s1 + " ) = " + s3;
            txt3.setText( s4  );  
        } 
        if ( e.getSource( ) == Arctan )  {   
            k3 = Math.atan( k1 );  k3 = k3*180/PI; 
            s3 = Double.toString( k3 );
            s4 = "Arctan( " + s1 + " ) = " + s3;
            txt3.setText( s4  );  
        } 
        if ( e.getSource( ) == Combinatory )  {   
            long n1, n2, n;  n1 = ( long ) k1;  n2 = ( long ) k2; 
            n = Factorial( n2 ) / ( Factorial( n1 ) * Factorial( n2 - n1 )  );
            s1 = Long.toString( n1 );  s2 = Long.toString( n2 );  
            s3 = Long.toString( n ); 
            s4 = "C( " + s1 + ", " + s2 + " ) = " + s3;
            txt3.setText( s4  );  
        } 
    }
    public static void main( String args[] )  {
        Calculator f = new Calculator( );
        f.setSize( 500, 500 );
        f.setVisible( true );
    }
}

这是我将此代码打包到JAR文件中的步骤 - 右键单击Project→Export→Java→JAR文件 →选择选项导出生成的类文件和资源，导出Java源文件和资源。我得到一个警告：带有编译警告的导出：Project 01 / src / Calculator.java 然后文件Calculator.jar在打包完成后无法运行。

您能否告诉我如何解决此错误？

Answer 1

您需要导出为可运行的jar文件，如下所示：

右键单击Project→Export→Java→Runnable JAR文件 enter image description here

确保在运行配置中选择Calculator，以便它知道哪个类具有main方法。

将它打包在jar文件中时，此代码无法运行

1 个答案: