我在外部类中创建新实例时，得到StackOverflow错误 [英] I get StackOverflow error when I create new instance in external class
本文介绍了我在外部类中创建新实例时，得到StackOverflow错误的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有我的主类CalculatorGUI.java和我的第二个类KeyHandler.java。如果我在外部类中创建我的主类的实例（例如CalculatorGUI one = new CalculatorGUI（）;），我得到：
I have my main class CalculatorGUI.java and my second class KeyHandler.java. If I create instance of my main class in external class (e.g. CalculatorGUI one = new CalculatorGUI();), I get:
Exception in thread "AWT-EventQueue-0" java.lang.StackOverflowError
为什么？我必须让这个实例使用y主GUI类的变量。
Why is that? I have to make this instance to use variables from y main GUI class.
这是我的CalculatorGUI类：
Here is my CalculatorGUI class:
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package gui;
/**
*
* @author Michał
*/
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.*;
public class CalculatorGUI extends javax.swing.JFrame {
public CalculatorGUI() {
initComponents();
}
private String value = "";
public void symbolControl(String s) {
//String str = String.valueOf(s);
boolean result;
result = value.endsWith(s);
if (result == true) {
int length = value.length();
value = value.substring(0, length - 1);
}
}
public void setValue(String s) {
value = s;
}
public String getValue() {
return value;
}
public void print(JButton b) {
value = value + b.getText();
jTextField1.setText(value);
}
KeyHandler keyboard = new KeyHandler();
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jTextField1 = new javax.swing.JTextField();
one = new javax.swing.JButton();
two = new javax.swing.JButton();
three = new javax.swing.JButton();
four = new javax.swing.JButton();
five = new javax.swing.JButton();
six = new javax.swing.JButton();
seven = new javax.swing.JButton();
eight = new javax.swing.JButton();
nine = new javax.swing.JButton();
zero = new javax.swing.JButton();
comma = new javax.swing.JButton();
multiply = new javax.swing.JButton();
plus = new javax.swing.JButton();
equals = new javax.swing.JButton();
divide = new javax.swing.JButton();
minus = new javax.swing.JButton();
del = new javax.swing.JButton();
lBracket = new javax.swing.JButton();
rBracket = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setTitle("Kalkulator");
jTextField1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jTextField1ActionPerformed(evt);
}
});
one.setText("1");
one.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
oneActionPerformed(evt);
}
});
one.addKeyListener(new java.awt.event.KeyAdapter() {
public void keyPressed(java.awt.event.KeyEvent evt) {
oneKeyPressed(evt);
}
});
two.setText("2");
two.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
twoActionPerformed(evt);
}
});
three.setText("3");
three.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
threeActionPerformed(evt);
}
});
four.setText("4");
four.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
fourActionPerformed(evt);
}
});
five.setText("5");
five.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
fiveActionPerformed(evt);
}
});
six.setText("6");
six.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
sixActionPerformed(evt);
}
});
seven.setText("7");
seven.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
sevenActionPerformed(evt);
}
});
eight.setText("8");
eight.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
eightActionPerformed(evt);
}
});
nine.setText("9");
nine.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
nineActionPerformed(evt);
}
});
zero.setText("0");
zero.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
zeroActionPerformed(evt);
}
});
comma.setText(".");
comma.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
commaActionPerformed(evt);
}
});
multiply.setText("*");
multiply.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
multiplyActionPerformed(evt);
}
});
plus.setText("+");
plus.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
plusActionPerformed(evt);
}
});
equals.setText("=");
equals.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
equalsActionPerformed(evt);
}
});
divide.setText("/");
divide.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
divideActionPerformed(evt);
}
});
minus.setText("-");
minus.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
minusActionPerformed(evt);
}
});
del.setText("<---");
del.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
delActionPerformed(evt);
}
});
lBracket.setText("(");
lBracket.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
lBracketActionPerformed(evt);
}
});
rBracket.setText(")");
rBracket.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
rBracketActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(jTextField1)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(four, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(seven, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(zero, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(one, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(two, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(five, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(eight, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(comma, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(nine, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(six, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(three, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
.addComponent(lBracket, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(plus, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(del, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
.addComponent(rBracket, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(minus, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(equals, javax.swing.GroupLayout.DEFAULT_SIZE, 48, Short.MAX_VALUE)))
.addGroup(layout.createSequentialGroup()
.addComponent(multiply, javax.swing.GroupLayout.PREFERRED_SIZE, 48, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(divide, javax.swing.GroupLayout.PREFERRED_SIZE, 48, javax.swing.GroupLayout.PREFERRED_SIZE)))))
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(one)
.addComponent(two)
.addComponent(three)
.addComponent(multiply)
.addComponent(divide))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(four)
.addComponent(five)
.addComponent(six)
.addComponent(plus)
.addComponent(minus))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(seven)
.addComponent(eight)
.addComponent(nine)
.addComponent(lBracket)
.addComponent(rBracket))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(zero)
.addComponent(comma)
.addComponent(del)
.addComponent(equals))
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void jTextField1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void equalsActionPerformed(java.awt.event.ActionEvent evt) {
}
private void oneActionPerformed(java.awt.event.ActionEvent evt) {
print(one);
}
private void twoActionPerformed(java.awt.event.ActionEvent evt) {
print(two);
}
private void threeActionPerformed(java.awt.event.ActionEvent evt) {
print(three);
}
private void fourActionPerformed(java.awt.event.ActionEvent evt) {
print(four);
}
private void fiveActionPerformed(java.awt.event.ActionEvent evt) {
print(five);
}
private void sixActionPerformed(java.awt.event.ActionEvent evt) {
print(six);
}
private void sevenActionPerformed(java.awt.event.ActionEvent evt) {
print(seven);
}
private void eightActionPerformed(java.awt.event.ActionEvent evt) {
print(eight);
}
private void nineActionPerformed(java.awt.event.ActionEvent evt) {
print(nine);
}
private void zeroActionPerformed(java.awt.event.ActionEvent evt) {
print(zero);
}
private void commaActionPerformed(java.awt.event.ActionEvent evt) {
String[] symbolArray = {"..", "+.", "-.", "*.", "/.", "(.", ")."};
value = value + comma.getText();
for (String symbolArray1 : symbolArray) {
symbolControl(symbolArray1);
}
jTextField1.setText(value);
}
private void multiplyActionPerformed(java.awt.event.ActionEvent evt) {
String symbol1 = "**";
String symbol2 = ".*";
value = value + multiply.getText();
symbolControl(symbol1);
symbolControl(symbol2);
jTextField1.setText(value);
}
private void divideActionPerformed(java.awt.event.ActionEvent evt) {
String symbol1 = "//";
String symbol2 = "./";
value = value + divide.getText();
symbolControl(symbol1);
symbolControl(symbol2);
jTextField1.setText(value);
}
private void plusActionPerformed(java.awt.event.ActionEvent evt) {
String symbol1 = "++";
String symbol2 = ".+";
value = value + plus.getText();
symbolControl(symbol1);
symbolControl(symbol2);
jTextField1.setText(value);
}
private void minusActionPerformed(java.awt.event.ActionEvent evt) {
String symbol1 = "--";
String symbol2 = ".-";
value = value + minus.getText();
symbolControl(symbol1);
symbolControl(symbol2);
jTextField1.setText(value);
}
private void delActionPerformed(java.awt.event.ActionEvent evt) {
int length = value.length();
String parametr = value.substring(0, length - 1);
value = parametr;
jTextField1.setText(value);
}
private void lBracketActionPerformed(java.awt.event.ActionEvent evt) {
String symbol1 = ")(";
String symbol2 = ".(";
value = value + lBracket.getText();
symbolControl(symbol1);
symbolControl(symbol2);
jTextField1.setText(value);
}
private void rBracketActionPerformed(java.awt.event.ActionEvent evt) {
String symbol1 = ".)";
String symbol2 = "()";
value = value + rBracket.getText();
symbolControl(symbol1);
symbolControl(symbol2);
jTextField1.setText(value);
}
private void oneKeyPressed(java.awt.event.KeyEvent evt) {
// TODO add your handling code here:
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(CalculatorGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(CalculatorGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(CalculatorGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(CalculatorGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new CalculatorGUI().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton comma;
private javax.swing.JButton del;
private javax.swing.JButton divide;
private javax.swing.JButton eight;
private javax.swing.JButton equals;
private javax.swing.JButton five;
private javax.swing.JButton four;
private javax.swing.JTextField jTextField1;
private javax.swing.JButton lBracket;
private javax.swing.JButton minus;
private javax.swing.JButton multiply;
private javax.swing.JButton nine;
public javax.swing.JButton one;
private javax.swing.JButton plus;
private javax.swing.JButton rBracket;
private javax.swing.JButton seven;
private javax.swing.JButton six;
private javax.swing.JButton three;
private javax.swing.JButton two;
private javax.swing.JButton zero;
// End of variables declaration
}
KayHandler.java：
KayHandler.java:
package gui;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
public class KeyHandler implements KeyListener {
CalculatorGUI elo = new CalculatorGUI();
/** Handle the key typed event from the text field. */
@Override
public void keyTyped(KeyEvent e) {
}
/** Handle the key-pressed event from the text field. */
@Override
public void keyPressed(KeyEvent e) {
}
/** Handle the key-released event from the text field. */
@Override
public void keyReleased(KeyEvent e) {
}
推荐答案
您有
class CalculatorGUI {
KeyHandler keyboard = new KeyHandler();
}
class KeyHandler {
CalculatorGUI elo = new CalculatorGUI();
}
创建一个新的CalculatorGUI创建一个新的KeyHandler，创建一个新的CalculatorGUI创建一个新的KeyHandler，创建一个新的CalculatorGUI，创建一个新的KeyHandler，创建一个新的CalculatorGUI，创建一个新的KeyHandler，... StackOverflow
Creating a new CalculatorGUI creates a new KeyHandler, which creates a new CalculatorGUI, which creates a new KeyHandler, which creates a new CalculatorGUI, which creates a new KeyHandler, which creates a new CalculatorGUI, which creates a new KeyHandler, ... StackOverflow
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