ex1.java

讲述各种各样的java初始编程 了解编程

/*
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package chenchao5;

/**
 *
 * @author williechen
 */
public class Ex1 {

    /**
     * @param args
     */
    private String firstArgs;
    private int secondArgs;
    private int thirdArgs;
    private String result;

    public static void main(String[] args) {
        Ex1 test = new Ex1();
        try {
            test.checkArgs(args);
            System.out.println(test.getResult());
        } catch (ArgsException e) {
            System.out.print(e.toString());
        }

    // TODO 自动生成方法存根

    }

    public String getResult() {
        result = firstArgs.substring(secondArgs, thirdArgs);
        return result;
    }

    protected void checkArgs(String[] pars) throws ArgsException {
        if (pars.length != 0) {
            switch (pars.length) {
                case 1:
                    throw new ArgsException(ArgsException.exceptions.SECONDLESS);
                case 2:
                    throw new ArgsException(ArgsException.exceptions.THIRDLESS);
                case 3:
                    setArgs(pars);
                    break;
                default:
                    throw new ArgsException(ArgsException.exceptions.NORMAL);
            }

        } else {
            throw new ArgsException(ArgsException.exceptions.FIRSTLESS);
        }

    }

    protected void setArgs(String[] pars) throws ArgsException {
        firstArgs = pars[0];
        try {
            secondArgs = Integer.parseInt(pars[1]);
        } catch (Exception e) {
            throw new ArgsException(ArgsException.exceptions.SECONDTYPEERROR);
        }
        try {
            thirdArgs = Integer.parseInt(pars[2]);
        } catch (Exception e) {
            throw new ArgsException(ArgsException.exceptions.THIRDTYPEERROR);
        }
        if (secondArgs > firstArgs.length()) {
            throw new ArgsException(ArgsException.exceptions.SECONDOUTBAND);
        }
        if (secondArgs + thirdArgs > firstArgs.length()) {
            throw new ArgsException(ArgsException.exceptions.THIRDOUTBAND);
        }

    }
}

class ArgsException extends Exception {

    private String errMsg = new String();

    public enum exceptions {

        NORMAL, FIRSTLESS, SECONDLESS, THIRDLESS, SECONDTYPEERROR, THIRDTYPEERROR, SECONDOUTBAND, THIRDOUTBAND
    } ;
    
    public ArgsException() {
        // TODO 自动生成构造函数存根
        errMsg = "ARGS Error!!!";
    }

    public ArgsException(exceptions e) {
        errMsg = "Please Input fellow the command format:\n" + "% java Probem3 hello 1 3\n";
        switch (e) {
            case NORMAL:
                errMsg = "Please Input fellow the command format:\n" + "% java Probem3 hello 1 3\n";
            case FIRSTLESS:
                errMsg += "Please input the frist parameter\n";
                break;
            case SECONDLESS:
                errMsg += "Please input the second parameter\n";
                break;
            case THIRDLESS:
                errMsg += "Please input the third parameter\n";
                break;
            case SECONDTYPEERROR:
                errMsg += "The second parameter must be a integer, like 1,2,3,...,9,10,11,...\n";
                break;
            case THIRDTYPEERROR:
                errMsg += "The third parameter must be a integer, like 1,2,3,...,9,10,11,...\n";
                break;
            case SECONDOUTBAND:
                errMsg += "The second parameter out of the String's length\n";
                break;
            case THIRDOUTBAND:
                errMsg += "The third parameter is too big, try a small one\n";
                break;
            default:
                break;
        }
    }

    @Override
    public String toString() {
        return errMsg;
    }
}