好吧，我知道我抓住并抛出例外情况很糟糕，但我无法解决这些问题。我想我可以通过几种不同的方式来实现它们。任何人都可以指导我正确的方向（不寻找完整的答案，只是代码应该是什么样的）？它被卡在＆＃34;抛出new（）;＆＃34;线和捕获块。其他一切似乎都没有任何问题。它应该是对以前项目http://pastebin.com/sjR0BZBY的改进。你可以运行这个，如果你想看看程序应该做什么，如果有帮助的话。
public class Project6 extends JFrame
{
// Declaring variables
private JLabel enterLabel, resultsLabel, errorLabel;
private JTextField queryField, errorField;
private JButton goB, clearB;
private JTextArea textArea;
private Container c;
private JPanel panel;
// main method
public static void main(String[] args)
{
Project6 p6 = new Project6();
p6.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
p6.setSize(new Dimension(455, 550));
p6.setVisible(true);
}
// creating JFrame
public Project6()
{
c = getContentPane();
c.setLayout(new FlowLayout());
setTitle("");
c.setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));
ButtonHandler handler = new ButtonHandler();
enterLabel = new JLabel("Enter query here:");
c.add(enterLabel);
queryField = new JTextField(35);
c.add(queryField);
goB = new JButton("GO!");
c.add(goB);
goB.addActionListener(handler);
resultsLabel = new JLabel("Results:");
c.add(resultsLabel);
textArea = new JTextArea(20, 30);
c.add(textArea);
errorLabel = new JLabel("-------------Error messages:");
c.add(errorLabel);
errorField = new JTextField(35);
c.add(errorField);
clearB = new JButton("Clear");
c.add(clearB);
clearB.addActionListener(handler);
}
// ActionListener for buttons
private class ButtonHandler implements ActionListener{
public void actionPerformed(ActionEvent e){
// Go! button
if (e.getSource() == goB){
String str = queryField.getText();
StringTokenizer tokens = new StringTokenizer(str, ", ");
int numToks = tokens.countTokens();
String[] tokenArray = new String[numToks];
int i = 0;
// creating all tokenizing, validations, and the works. Try and bear with it, it works but it's a rough trip
while (tokens.hasMoreTokens()){
// while loop to create tokens
while (tokens.hasMoreTokens()){
str = tokens.nextToken();
tokenArray[i] = str;
System.out.println(tokenArray[i]);
i++; }
// start if verifications, everything else
String query = tokenArray[3];
String optok = tokenArray[4];
String index = tokenArray[5];
String qField = queryField.getText();
try {
if (qField.equals(""))
throw new MissingInputException();
else {
if (numToks != 6)
throw new IncorrectFormatException();
else {
if (tokenArray[0].equalsIgnoreCase("Report"))
{
if (tokenArray[1].equalsIgnoreCase("all"))
{
if (tokenArray[2].equals("where"))
{
if (tokenArray[3].equals("basePrice") || tokenArray[3].equals("quality") || tokenArray[3].equals("numInStock"))
{
if (tokenArray[4].equals("<") || tokenArray[4].equals(">") || tokenArray[4].equals(">=")||tokenArray[4].equals("<=")||tokenArray[4].equals("=="))
{
if (query.equals("basePrice"))
{ BasePriceM(query, index, optok); }
else if (query.equals("quality"))
{ QualityM(query, index, optok); }
else if (query.equals("numInStock"))
{ NumInStockM(query, index, optok); }
}
else
throw new InvalidOperatorException();
}
else
throw new InvalidLValueException();
}
else
throw new InvalidQualifierException();
}
else
throw new InvalidSelectorException();
}
else
throw new IllegalStartOfQueryException();
}
}
} // end try
catch(MissingInputException aa)
{
errorField.setText("Enter an expression");
queryField.setText("");
}
catch(IncorrectFormatException ab)
{
errorField.setText("Error, field too large or small");
queryField.setText("");
}
catch(IllegalStartOfQueryException ac)
{
errorField.setText("Error, report expected");
queryField.setText("");
}
catch(InvalidSelectorException ad)
{
errorField.setText("Error, all expected");
queryField.setText("");
}
catch(InvalidQualifierException ae)
{
errorField.setText("Error, where expected");
queryField.setText("");
}
catch(InvalidLValueException af)
{
errorField.setText("Error, basePrice, Quality, numInStock expected");
queryField.setText("");
}
catch(InvalidOperatorException ag)
{
errorField.setText("Error, < > >= <= == expected");
queryField.setText("");
}
catch(NumberFormatException af)
{
}
}// end of while loop
} // end go button
// clear all button
if (e.getSource() == clearB)
{
queryField.setText("");
textArea.setText("");
errorField.setText("");
}
}
} // end buttons
// methods for printing
public void BasePriceM(String query, String index, String optok)
{
int pos = 0;
int index1 = index.indexOf(".", pos);
if (index1 > -1)
{
double b = Double.parseDouble(index);
if (b > 0.05 && b < 5400.0)
{printBasePrice(query, optok, b);}
else{
errorField.setText("Invalid query, must be between 0.05 and 5400.0");
queryField.setText(""); }}
}
public void QualityM(String query, String index, String optok)
{
int pos2 = 0;
int index2 = index.indexOf(".", pos2);
if (index2 == -1)
{
int n = Integer.parseInt(index);
if (n > 0)
{
printBasePrice(query, optok, n);
}
else{
errorField.setText("Invalid query, must be greater than 0");
queryField.setText(""); }}
}
public void NumInStock(String query, String index, String optok)
{
int pos2 = 0;
int index2 = index.indexOf(".", pos2);
if (index2 == -1)
{
int n = Integer.parseInt(index);
if (n > 0)
{
printBasePrice(query, optok, n);
}
else{
errorField.setText("Invalid query, must be greater than 0");
queryField.setText("");} }
}
public void printQuality(String query, String optok, int p)
{
textArea.append("Search for " + query +" "+ optok +" "+ p + "\n");
}
public void printBasePrice(String query, String optok, double b)
{
textArea.append("Search for " + query +" "+ optok +" "+ b + "\n");
}
public void printNumInStock(String query, String optok, int n)
{
textArea.append("Search for " + query +" "+ optok +" "+ n + "\n");
}
} // end program`enter code here`