可能重复：
Causes of 'java.lang.NoSuchMethodError: main Exception in thread “main”'
我收到以下错误：
java.lang.NoSuchMethodError：main 线程“main”中的异常
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.util.*;
import java.io.*;
public class SwimCalc extends JFrame implements ActionListener {
private JTabbedPane jtabbedPane;
private JPanel Customers;
JTextArea NameTextCustomers, ExistTextCustomers, NameTextContractors,
ExistTextContractors;
public SwimCalc() {
setTitle("Volume Calculator");
setSize(300, 200);
JPanel topPanel = new JPanel();
topPanel.setLayout(new BorderLayout());
getContentPane().add(topPanel);
createCustomers();
jtabbedPane = new JTabbedPane();
jtabbedPane.addTab("Customers", Customers);
topPanel.add(jtabbedPane, BorderLayout.CENTER);
}
/* CREATE CUSTOMERS */
public JPanel createCustomers() {
Customers = new JPanel();
Customers.setLayout(null);
NameTextCustomers = new JTextArea();
NameTextCustomers.setBounds(10, 10, 350, 150);
NameTextCustomers.setLineWrap(true);
Customers.add(NameTextCustomers);
JButton Exit = new JButton("Exit");
Exit.setBounds(30, 170, 80, 20);
Exit.addActionListener(this);
Exit.setBackground(Color.white);
Customers.add(Exit);
JButton AddCustomers = new JButton("Add Customer");
AddCustomers.setBounds(130, 170, 120, 20);
AddCustomers.setBackground(Color.white);
Customers.add(AddCustomers);
JButton Refresh = new JButton("Refresh");
Refresh.setBounds(260, 170, 80, 20);
Refresh.setBackground(Color.white);
Customers.add(Refresh);
ExistTextCustomers = new JTextArea();
ExistTextCustomers.setBounds(10, 200, 350, 60);
ExistTextCustomers.setLineWrap(true);
Customers.add(ExistTextCustomers);
final JTextArea custArea = new JTextArea(6, 30);
final JTextArea custMessage = null;
AddCustomers.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
new Customer("Customer");
}
});
Customers.add(custArea);
Customers.add(AddCustomers);
Customers.add(Refresh);
Customers.add(custMessage);
Refresh.setMnemonic('R');
Refresh.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
custMessage.setText("");
try {
File custOpen = new File("customer.txt");
FileReader custAreaIn = new FileReader(custOpen);
custArea.read(custAreaIn, custOpen.toString());
custMessage.setText("The file exists and can be read from.");
} catch (IOException e3) {
custMessage.setText("The file could not be read. "
+ e3.getMessage());
}
}
});
return Customers;
}
class Customer extends JFrame {
private String[] states = { "AL", "AK", "AZ", "AR", "CA", "CO", "CT",
"DE", "FL", "GA", "HI", "ID", "IL", "IN", "IA", "KS", "KY", "LA",
"ME", "MD", "MA", "MI", "MN", "MS", "MO", "MT", "NE", "NV", "NH",
"NJ", "NM", "NY", "NC", "ND", "OH", "OK", "OR", "PA", "RI", "SC",
"SD", "TN", "TX", "UT", "VT", "VA", "WA", "WV", "WI", "WY" };
private JComboBox StateList = new JComboBox(states);
private JTextField NameText = new JTextField(25);
private JTextField AddressText = new JTextField(25);
private JTextField CityText = new JTextField(25);
private JTextField ZipText = new JTextField(9);
private JTextField PhoneText = new JTextField(10);
private JTextField PopMessageText = new JTextField(30);
private static final long serialVersionUID = 1L;
private AddCustButtonHandler addCusHandler = new AddCustButtonHandler();
public Customer(String who) {
popUpWindow(who);
}
public void popUpWindow(final String who) {
final JFrame popWindow;
popWindow = new JFrame(who);
popWindow.setSize(425, 350);
popWindow.setLocation(100, 100);
popWindow.setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
Container c = new Container();
popWindow.add(c);
c.setLayout(new FlowLayout());
JPanel one = new JPanel();
JPanel two = new JPanel();
JPanel three = new JPanel();
JPanel four = new JPanel();
JPanel five = new JPanel();
JPanel six = new JPanel();
one.add(new JLabel(who + " Name "));
one.add(NameText);
two.add(new JLabel("Address "));
two.add(AddressText);
three.add(new JLabel("City "));
three.add(CityText);
four.add(new JLabel("State "));
StateList.setSelectedIndex(0);
four.add(StateList);
four.add(new JLabel("ZIP"));
four.add(ZipText);
four.add(new JLabel("Phone"));
four.add(PhoneText);
JButton addwho = new JButton("Add " + who);
addwho.setMnemonic('A');
JButton close = new JButton("Close");
close.setMnemonic('C');
JButton deleteFile = new JButton("Delete File");
deleteFile.setMnemonic('D');
five.add(addwho);
five.add(close);
five.add(deleteFile);
PopMessageText.setEditable(false);
PopMessageText.setHorizontalAlignment(JTextField.CENTER);
six.add(PopMessageText);
c.add(one);
c.add(two);
c.add(three);
c.add(four);
c.add(five);
c.add(six);
deleteFile.setToolTipText("Delete File");
addwho.setToolTipText("Add " + who);
close.setToolTipText("Close");
if (who == "Customer")
addwho.addActionListener(addCusHandler);
close.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
NameText.setText("");
AddressText.setText("");
CityText.setText("");
ZipText.setText("");
PhoneText.setText("");
PopMessageText.setText("");
popWindow.dispose();
}
});
deleteFile.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
PopMessageText.setText("");
if (who == "Customer") {
File file = new File("Customer.txt");
boolean cusFileDeleted = file.delete();
if (cusFileDeleted) {
PopMessageText.setText("Customer file has been deleted");
} else {
PopMessageText
.setText("There was an erron in deleting file");
}
}
}
});
}
class AddCustButtonHandler implements ActionListener {
public void actionPerformed(ActionEvent addCusHandler) {
int StateIndex;
try {
File file = new File("Customer.txt");
boolean success = file.createNewFile();
if (success) {
PopMessageText
.setText("Customer.txt file created file added");
} else if (file.canWrite()) {
PopMessageText
.setText("Writing data to Customer.txt, file added");
} else {
PopMessageText.setText("Cannot create file: Customer.txt");
}
try {
FileWriter fileW = new FileWriter("Customer.txt", true);
fileW.write(NameText.getText());
fileW.write(",");
fileW.write(AddressText.getText());
fileW.write(",");
fileW.write(CityText.getText());
fileW.write(",");
StateIndex = StateList.getSelectedIndex();
fileW.write(states[StateIndex]);
fileW.write(",");
fileW.write(ZipText.getText());
fileW.write(",");
fileW.write(PhoneText.getText());
fileW.write("\r\n");
fileW.close();
PopMessageText.setText("A new Customer has been added!");
FileReader fileR = new FileReader("Customer.txt");
BufferedReader buffIn = new BufferedReader(fileR);
String textData = buffIn.readLine();
buffIn.close();
} catch (IOException e1) {
JOptionPane.showMessageDialog(null, e1.getMessage(), "ERROR",
2);
}
NameText.setText("");
AddressText.setText("");
CityText.setText("");
ZipText.setText("");
PhoneText.setText("");
} catch (IOException e1) {
}
}
}
public void actionPerformed(ActionEvent event) {
}
private void Exit_pressed() {
System.exit(0);
}
public void main(String[] args) {
JFrame frame = new SwimCalc();
frame.setSize(380, 350);
frame.setVisible(true);
}
}
public void actionPerformed(ActionEvent e) {
}
}
错误：
java.lang.NoSuchMethodError：main 线程“main”中的异常
public void actionPerformed(ActionEvent e) {
}
public static void main(String[] args){
JFrame frame = new SwimCalc();
frame.setSize(380, 350);
frame.setVisible(true);
}
}
答案 0 :(得分：7)
main需要是静态方法。
public static void main(String[] args){
JFrame frame = new SwimCalc();
frame.setSize(380, 350);
frame.setVisible(true);
}
此外，main方法应该在SwimCalc类或其他一些顶级类中。将方法移动到SwimCalc类（不在Customer类中）并使用java SwimCalc来调用它。您不能在内部类中声明main。
答案 1 :(得分：2)
看来您的main方法实际上是 你的actionPerformed方法。你显然不能这样做。声明需要在您的SwimCalc课程中。那种疯狂是你试图运行的实际代码吗？你到处都有括号和流浪的括号，没有缩进;如果你只是清理你的代码，问题会更容易找到。
和
public void main(String[] args){
应该是
public static void main(String[] args){
还有这样的废话：} );。你有很多语法错误...
答案 2 :(得分：2)
是签名应该是
public static void main(String[] args)
即使错过了args，eclipse也会抛出此错误。
答案 3 :(得分：0)
public **static** void main(String[] args){
答案 4 :(得分：0)
主要方法必须是公共静态
public static void main(String[] args)
答案 5 :(得分：0)
main()必须是静态的。完整的签名是：
public static void main(String[] args)
答案 6 :(得分：0)
应该是
public static void main(String[] args){
而不是public void main ...
答案 7 :(得分：0)
您的主要方法需要是静态的。这应该是签名：
public static void main(String[] args)