如何将 JTextField 输入转换为 int 以进行验证？
How can I convert JTextField input into int for validation?
我需要帮助将文本字段输入转换为 int 以进行验证。
contactnum 来自字段 textFieldContactnum。
我想将 textFieldContactnum 的输入转换为 int。
我试过先将 textFieldContactnum.getText() 存储到一个字符串中，然后使用一个新的 int (contactnumber) 来解析 (Integer.parseInt)，就像下面的代码一样……
private void actionPerformedOk() {
String username = textFieldUsername.getText();
String password = passwordField.getText();
String email = textFieldEmail.getText();
String securityqn = textFieldSecurityqn.getText();
String securityanswer = textFieldSecurityanswer.getText();
contactnumber = textFieldContactnum.getText();
int contactnum = Integer.parseInt(contactnumber);
String firstname = textFieldFirstName.getText();
String lastname = textFieldLastName.getText();
String gender = genderSelected;
String nric = textFieldNRIC.getText();
String address = textFieldAddress.getText();
postalcode1 = textFieldPostalCode.getText();
int postalcode = Integer.parseInt(postalcode1);
String day = dayList.getSelectedItem().toString();
String month = monthList.getSelectedItem().toString();
String year = yearList.getSelectedItem().toString();
if (!day.equals("Day") && !month.equals("Month") && !year.equals("Year")) {
dateAsString = day + "/" + month + "/" + year;
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
try {
Date date = sdf.parse(dateAsString);
System.out.println(date);
} catch (ParseException e1) {}
}
dateAsString = day + ("/") + month + ("/") + year;
String date = dateAsString;
// retrieve the user input from the text box/area provided
if (validateInput()) {
username = textFieldUsername.getText();
if (actions.equalsIgnoreCase("Submit")){
signup = new hiroSIGNUP(username, password, email, securityqn, securityanswer, contactnum, firstname, lastname, gender, nric, address, postalcode, date);
actionPerformedCreate();
}
else{
// update the values of the current expense object
//update empty to some fields
signup.setUsername(username);
signup.setPassword(password);
signup.setEmail(email);
signup.setSecurityqn(securityqn);
signup.setSecurityanswer(securityanswer);
signup.setContactnum(contactnum);
signup.setFirstname(firstname);
signup.setLastname(lastname);
signup.setGender(gender);
signup.setNric(nric);
signup.setAddress(address);
signup.setPostalcode(postalcode);
signup.setDate(date);
actionPerformedUpdate();
}
}
}
/**
* Purpose: This method updates the expense record
* in the database.
* Input: Nil
* Return: void
*/
public void actionPerformedUpdate(){
// Update record in database and check return value
if (SignupDA.updatehiroSIGNUP(signup)) {
JOptionPane.showMessageDialog(myFrame,
"Record updated successfully", "Alert",
JOptionPane.INFORMATION_MESSAGE);
// reset text field for next record.
textFieldUsername.setEditable(false);
passwordField.setEditable(false);
textFieldEmail.setEditable(false);
textFieldSecurityqn.setEditable(false);
textFieldSecurityanswer.setEditable(false);
textFieldContactnum.setEditable(false);
textFieldFirstName.setEditable(false);
textFieldLastName.setEditable(false);
dayList.setEditable(false);
monthList.setEditable(false);
yearList.setEditable(false);
textFieldNRIC.setEditable(false);
textFieldAddress.setEditable(false);
textFieldPostalCode.setEditable(false);
}
else {
JOptionPane.showMessageDialog(myFrame,
"Database Error. Record not updated.", "Alert",
JOptionPane.ERROR_MESSAGE);
}
}
/**
* Purpose: This method creates the expense record
* in the database.
* Input: Nil
* Return: void
*/
public void actionPerformedCreate(){
// insert to database and check return value
if (SignupDA.createhiroSIGNUP(signup)) {
JOptionPane.showMessageDialog(myFrame,
"Record created successfully", "Alert",
JOptionPane.INFORMATION_MESSAGE);
// reset text field for next record.
// reset text field for next record.
textFieldUsername.setText("");
passwordField.setText("");
textFieldEmail.setText("");
textFieldSecurityqn.setText("");
textFieldSecurityanswer.setText("");
textFieldContactnum.setText("");
textFieldFirstName.setText("");
textFieldLastName.setText("");
group.clearSelection();
textFieldNRIC.setText("");
textFieldAddress.setText("");
textFieldPostalCode.setText("");
}
else
JOptionPane.showMessageDialog(myFrame,
"Database Error. Record not created.", "Alert",
JOptionPane.ERROR_MESSAGE);
}
private boolean validateInput() {
boolean result = false;
String msg = "";
int msgType = JOptionPane.ERROR_MESSAGE;
// retrieve the user input from the text box/area provided
String username = textFieldUsername.getText();
String password = passwordField.getText();
String email = textFieldEmail.getText();
String securityqn = textFieldSecurityqn.getText();
String securityanswer = textFieldSecurityanswer.getText();
int contactnum = Integer.parseInt(contactnumber);
String firstname = textFieldFirstName.getText();
String lastname = textFieldLastName.getText();
String gender = genderSelected;
//FIND OUT HOW TO VALIDATE GENDER RADIO BUTTON
String nric = textFieldNRIC.getText();
String address = textFieldAddress.getText();
int postalcode = Integer.parseInt(postalcode1);
String date = dateAsString;
if (username.length() == 0)
msg += "Please enter Username.\n";
if (password.length() == 0)
msg += "Please enter password.\n";
if (email.length() == 0)
msg += "Please enter Email.\n";
if (securityqn.length() == 0)
msg += "Please enter Security Question.\n";
if (securityanswer.length() == 0)
msg += "Please enter Security Answer\n";
if (contactnumber.length() == 0)
msg += "Please enter Contact Number\n";
if (firstname.length() == 0)
msg += "Please enter First name\n";
if (lastname.length() == 0)
msg += "Please enter Last name\n";
if (genderSelected.length() == 0)
msg += "Please enter Gender\n";
if (nric.length() == 0)
msg += "Please enter NRIC\n";
if (address.length() == 0)
msg += "Please enter Address\n";
if (postalcode1.length() == 0)
msg += "Please enter Postal code\n";
if (date.length() == 0)
msg += "Please enter Date\n";
if (msg.length() == 0)
result = true;
else
JOptionPane.showMessageDialog(myFrame, msg, "Alert", msgType);
return result;
}
/**
* @wbp.parser.constructor
*/
public hiroSIGNUPPanel(JFrame mf, String action, hiroSIGNUP s){
this(mf, action);
//display the current expense information
signup = s;
textFieldUsername.setText(s.getUsername());
passwordField.setText(s.getPassword());
textFieldEmail.setText(s.getEmail());
textFieldSecurityqn.setText(s.getSecurityqn());
textFieldSecurityanswer.setText(s.getSecurityanswer());
textFieldContactnum.setText(String.valueOf(s.getContactnum()));
textFieldFirstName.setText(s.getFirstname());
textFieldLastName.setText(s.getLastname());
//textFieldGender.setText(s.getGender());
textFieldNRIC.setText(s.getNric());
textFieldAddress.setText(s.getAddress());
textFieldPostalCode.setText(String.valueOf(s.getPostalcode()));
}
}
我的错误是
Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at hiroApp.ui.hiroSIGNUPPanel.actionPerformedOk(hiroSIGNUPPanel.java:781)
在解析之前你可以尝试检查
if(contactnumber.trim().length() == 0) {
}
您可能还想使用 long，因为 int 无法存储 10 位数字的联系电话。
您的答案在错误消息中：对于输入字符串：“”
注意它是一个空字符串。
所以当你调用以下...
int contactnum = Integer.parseInt(contactnumber);
Java 如果没有任何内容，则无法将字符串解析为 int。
你可以这样处理这个错误：
try{
int contactnum = Integer.parseInt(contactnumber);
catch(Exception e){
System.out.println("Your Textfield is empty or filled in with letters");
}
通过这种处理，程序会捕获错误并且不会崩溃。
我需要帮助将文本字段输入转换为 int 以进行验证。 contactnum 来自字段 textFieldContactnum。 我想将 textFieldContactnum 的输入转换为 int。 我试过先将 textFieldContactnum.getText() 存储到一个字符串中，然后使用一个新的 int (contactnumber) 来解析 (Integer.parseInt)，就像下面的代码一样……
private void actionPerformedOk() {
String username = textFieldUsername.getText();
String password = passwordField.getText();
String email = textFieldEmail.getText();
String securityqn = textFieldSecurityqn.getText();
String securityanswer = textFieldSecurityanswer.getText();
contactnumber = textFieldContactnum.getText();
int contactnum = Integer.parseInt(contactnumber);
String firstname = textFieldFirstName.getText();
String lastname = textFieldLastName.getText();
String gender = genderSelected;
String nric = textFieldNRIC.getText();
String address = textFieldAddress.getText();
postalcode1 = textFieldPostalCode.getText();
int postalcode = Integer.parseInt(postalcode1);
String day = dayList.getSelectedItem().toString();
String month = monthList.getSelectedItem().toString();
String year = yearList.getSelectedItem().toString();
if (!day.equals("Day") && !month.equals("Month") && !year.equals("Year")) {
dateAsString = day + "/" + month + "/" + year;
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
try {
Date date = sdf.parse(dateAsString);
System.out.println(date);
} catch (ParseException e1) {}
}
dateAsString = day + ("/") + month + ("/") + year;
String date = dateAsString;
// retrieve the user input from the text box/area provided
if (validateInput()) {
username = textFieldUsername.getText();
if (actions.equalsIgnoreCase("Submit")){
signup = new hiroSIGNUP(username, password, email, securityqn, securityanswer, contactnum, firstname, lastname, gender, nric, address, postalcode, date);
actionPerformedCreate();
}
else{
// update the values of the current expense object
//update empty to some fields
signup.setUsername(username);
signup.setPassword(password);
signup.setEmail(email);
signup.setSecurityqn(securityqn);
signup.setSecurityanswer(securityanswer);
signup.setContactnum(contactnum);
signup.setFirstname(firstname);
signup.setLastname(lastname);
signup.setGender(gender);
signup.setNric(nric);
signup.setAddress(address);
signup.setPostalcode(postalcode);
signup.setDate(date);
actionPerformedUpdate();
}
}
}
/**
* Purpose: This method updates the expense record
* in the database.
* Input: Nil
* Return: void
*/
public void actionPerformedUpdate(){
// Update record in database and check return value
if (SignupDA.updatehiroSIGNUP(signup)) {
JOptionPane.showMessageDialog(myFrame,
"Record updated successfully", "Alert",
JOptionPane.INFORMATION_MESSAGE);
// reset text field for next record.
textFieldUsername.setEditable(false);
passwordField.setEditable(false);
textFieldEmail.setEditable(false);
textFieldSecurityqn.setEditable(false);
textFieldSecurityanswer.setEditable(false);
textFieldContactnum.setEditable(false);
textFieldFirstName.setEditable(false);
textFieldLastName.setEditable(false);
dayList.setEditable(false);
monthList.setEditable(false);
yearList.setEditable(false);
textFieldNRIC.setEditable(false);
textFieldAddress.setEditable(false);
textFieldPostalCode.setEditable(false);
}
else {
JOptionPane.showMessageDialog(myFrame,
"Database Error. Record not updated.", "Alert",
JOptionPane.ERROR_MESSAGE);
}
}
/**
* Purpose: This method creates the expense record
* in the database.
* Input: Nil
* Return: void
*/
public void actionPerformedCreate(){
// insert to database and check return value
if (SignupDA.createhiroSIGNUP(signup)) {
JOptionPane.showMessageDialog(myFrame,
"Record created successfully", "Alert",
JOptionPane.INFORMATION_MESSAGE);
// reset text field for next record.
// reset text field for next record.
textFieldUsername.setText("");
passwordField.setText("");
textFieldEmail.setText("");
textFieldSecurityqn.setText("");
textFieldSecurityanswer.setText("");
textFieldContactnum.setText("");
textFieldFirstName.setText("");
textFieldLastName.setText("");
group.clearSelection();
textFieldNRIC.setText("");
textFieldAddress.setText("");
textFieldPostalCode.setText("");
}
else
JOptionPane.showMessageDialog(myFrame,
"Database Error. Record not created.", "Alert",
JOptionPane.ERROR_MESSAGE);
}
private boolean validateInput() {
boolean result = false;
String msg = "";
int msgType = JOptionPane.ERROR_MESSAGE;
// retrieve the user input from the text box/area provided
String username = textFieldUsername.getText();
String password = passwordField.getText();
String email = textFieldEmail.getText();
String securityqn = textFieldSecurityqn.getText();
String securityanswer = textFieldSecurityanswer.getText();
int contactnum = Integer.parseInt(contactnumber);
String firstname = textFieldFirstName.getText();
String lastname = textFieldLastName.getText();
String gender = genderSelected;
//FIND OUT HOW TO VALIDATE GENDER RADIO BUTTON
String nric = textFieldNRIC.getText();
String address = textFieldAddress.getText();
int postalcode = Integer.parseInt(postalcode1);
String date = dateAsString;
if (username.length() == 0)
msg += "Please enter Username.\n";
if (password.length() == 0)
msg += "Please enter password.\n";
if (email.length() == 0)
msg += "Please enter Email.\n";
if (securityqn.length() == 0)
msg += "Please enter Security Question.\n";
if (securityanswer.length() == 0)
msg += "Please enter Security Answer\n";
if (contactnumber.length() == 0)
msg += "Please enter Contact Number\n";
if (firstname.length() == 0)
msg += "Please enter First name\n";
if (lastname.length() == 0)
msg += "Please enter Last name\n";
if (genderSelected.length() == 0)
msg += "Please enter Gender\n";
if (nric.length() == 0)
msg += "Please enter NRIC\n";
if (address.length() == 0)
msg += "Please enter Address\n";
if (postalcode1.length() == 0)
msg += "Please enter Postal code\n";
if (date.length() == 0)
msg += "Please enter Date\n";
if (msg.length() == 0)
result = true;
else
JOptionPane.showMessageDialog(myFrame, msg, "Alert", msgType);
return result;
}
/**
* @wbp.parser.constructor
*/
public hiroSIGNUPPanel(JFrame mf, String action, hiroSIGNUP s){
this(mf, action);
//display the current expense information
signup = s;
textFieldUsername.setText(s.getUsername());
passwordField.setText(s.getPassword());
textFieldEmail.setText(s.getEmail());
textFieldSecurityqn.setText(s.getSecurityqn());
textFieldSecurityanswer.setText(s.getSecurityanswer());
textFieldContactnum.setText(String.valueOf(s.getContactnum()));
textFieldFirstName.setText(s.getFirstname());
textFieldLastName.setText(s.getLastname());
//textFieldGender.setText(s.getGender());
textFieldNRIC.setText(s.getNric());
textFieldAddress.setText(s.getAddress());
textFieldPostalCode.setText(String.valueOf(s.getPostalcode()));
}
}
我的错误是
Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at hiroApp.ui.hiroSIGNUPPanel.actionPerformedOk(hiroSIGNUPPanel.java:781)
在解析之前你可以尝试检查
if(contactnumber.trim().length() == 0) {
}
您可能还想使用 long，因为 int 无法存储 10 位数字的联系电话。
您的答案在错误消息中：对于输入字符串：“”
注意它是一个空字符串。
所以当你调用以下...
int contactnum = Integer.parseInt(contactnumber);
Java 如果没有任何内容，则无法将字符串解析为 int。
你可以这样处理这个错误：
try{
int contactnum = Integer.parseInt(contactnumber);
catch(Exception e){
System.out.println("Your Textfield is empty or filled in with letters");
}
通过这种处理，程序会捕获错误并且不会崩溃。