异常捕捉不到

这个程序是用来返回键盘输入的各种类型的数据项的方法
这是第一个文件，
package FormattedInput;
import java.io.*;

public class FormattedInput {

private int readToken( ) {

try {

ttype = tokenizer.nextToken( );
return ttype;

}catch(IOException e ) {

e.printStackTrace( System.err );
System.exit( 1 );

}

return 0;

}

public int readInt( ) throws InvalidUserInputException {

if( readToken( ) != tokenizer.TT_NUMBER ) {

throw new InvalidUserInputException( " readInt( ) faild ."
+ "Input data not numeric." );

}

if( tokenizer.nval > ( double ) Integer.MAX_VALUE ||
tokenizer.nval < ( double ) Integer.MIN_VALUE ) {

throw new InvalidUserInputException( " readInt( ) faild ."
+ "Input data not numeric." );

}

if( tokenizer.nval != ( double ) ( int ) tokenizer.nval ) {

throw new InvalidUserInputException( " readInt( ) faild ."
+ "Input data not numeric." );