Java随机数的例子

该例子演示了随机数的产生，可通过设置最低数（minNum）和最高数(maxNum)以控制随机数的产生范围。
程序当前最低数固定为0，将从控制台上接收输入的数字作为最高数。
例子相对简单，仅供初学者参考。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Random;


public class GRandom {

	/**
	 * @author Jaenson
	 * @since 03/17/2011
	 */
	private int minNum=0;
	private int maxNum=0;
	private static InputStreamReader in;   
	private static BufferedReader reader;  
	
	public GRandom(){
		in = new InputStreamReader(System.in);   
		reader = new BufferedReader(in);  
	}
	
	public String GenerateRandomNum(int tarMinNum, int tarMaxNum){
		String result="";
		Random random = new Random();
		
		/* Set Random Seed 
		Long longNum = System.currentTimeMillis();
		random.setSeed(longNum);
		*/
		
		/* Boolean 
		String.valueOf(random.nextBoolean());
		*/
		
		/* Double 
		String.valueOf(random.nextDouble());
		*/
		
		/* Float
		String.valueOf(random.nextFloat());
		*/
		
		/* Long 
		String.valueOf(random.nextLong());
		*/
		
		/* Gaussian Algorithm 
		String.valueOf(random.nextGaussian());
		*/
		
		/* Integer */
		int n = tarMaxNum - tarMinNum + 1;
		int i = random.nextInt(tarMaxNum) % n;
		result = String.valueOf(tarMinNum + i);
		
		return result;
	}
	
	public String readString() throws Exception{
		String s = "";   
		char temp;
		try{   
			s = reader.readLine();   
		}catch(IOException e){
			System.out.println("Input error! Please restart the application.");
			temp = (char) System.in.read();
			System.exit(0);   
		}catch(Exception e){
			System.out.println("Input error! Please restart the application.");
			temp = (char) System.in.read();
			System.exit(0); 
		}
		return s;   
	}   

	
	public int printConsoleChar() throws IllegalArgumentException, Exception{
		int random = 0;
		char temp='a';
		try{
			minNum = 0;
			
			System.out.print("Enter the number(Integer):"); 
			maxNum = Integer.parseInt(readString());
                            /* Generate 100 times */
			for(int i=0; i<100; i++){
			random = Integer.parseInt(GenerateRandomNum(minNum, maxNum));
			System.out.println("Random Number:"+random);
			}
		}catch(IOException e){
			System.out.println("Input error! Please restart the application.");
			temp = (char) System.in.read();
			System.exit(0);
		}catch(IllegalArgumentException e){
			System.out.println("Illegal number! Please restart the application.");
			temp = (char) System.in.read();
			System.exit(0);
		}catch(Exception e){
			System.out.println("Input error! Please restart the application.");
			temp = (char) System.in.read();
			System.exit(0);
		}
		return random;
	}

	public static void main(String[] args) throws Exception{
		// TODO Auto-generated method stub
		GRandom GR= new GRandom();
		GR.printConsoleChar();
	}

}