1、文件读取并打印

import java.io.*;

public class readandprint{

//*********Found********

public static void main(String args[]) throws Exception{

long filePoint = 0 ;

String s;

RandomAccessFile file = new RandomAccessFile("D:\\javaceshu\\readandprint.java","r");

long fileLength = file.length();

while (filePoint<fileLength){

//*********Found********

s = file.readLine();

System.out.println(s); 

filePoint = file.getFilePointer();

                            }

file.close();

    }

}

2、图形程序显示乘法

import javax.swing.JOptionPane;

public class Java_1 {

public static void main( String args[] ) {

int x, y, result;

String xVal, yVal;

xVal = JOptionPane.showInputDialog( "输入第1个整数:" );

yVal = JOptionPane.showInputDialog( "输入第2个整数:" );

//*********Found********

x = Integer.parseInt(xVal);

y = Integer.parseInt( yVal );

result = x * y;

//*********Found********

JOptionPane.showMessageDialog( null, "两个数的积: " + result );

System.exit( 0 );

}

}

3、从命令行参数输入 java_24_3 7 （先编译完后）会显示7的阶乘是5040

public class _24_3{

public static void main(String[] args){

String num;

if(args.length > 0)

//*********Found********

num =args[0];

else

num = "5";

//*********Found********

int input = Integer.parseInt(num);

int result = Java_3(input);

System.out.println(input+ " 的阶乘是 "+ result);

}

public static int Java_3(int x)

{

if( x < 0 )

return 0;

int fact = 1;

while(x > 1)

{

//*********Found********

fact = fact * x;

x = x-1;

}

return fact;

}

}