readdoubletest.java

Java2核心技术卷一 配套源码,看了还不错

/**
 * @version 1.00 11 Mar 1997
 * @author Cay Horstmann
 */
 
import java.io.*;
import java.text.*;

public class ReadDoubleTest 
   // shows how to read a double the hard way
{  public static void main(String[] args) 
   {  System.out.println
         ("Enter a number, I'll add two to it.");
      double x; // the number we wish to read
      try
      {  InputStreamReader isr 
            = new InputStreamReader(System.in);
         BufferedReader br 
            = new BufferedReader(isr);
         String s = br.readLine(); 
         DecimalFormat df = new DecimalFormat();
         Number n = df.parse(s);
         x = n.doubleValue();
      }
      catch(IOException e)
      {  x = 0;
      }
      catch(ParseException e)
      {  x = 0;
      }
      System.out.println(x + 2); 
   }
}