java – 我在调用构造函数时遇到错误(我认为)不知道如何解决它
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我在Java课程中有这个项目,我选择制作超市送货服务,它提供以下内容：
– 产品及其价格.
– 选择产品数量的能力.
– 用户提供他的电话号码,因此送货员可以联系他们以获取指示.
– 用户可以输入折扣代码.
– 用户可以取消订单或确认订单,当用户确认时,帐单上印有订单即将到达的备注.
– 用户可以输入他们将交付的金额,因此送货员可以带来变更.
我修改了这个代码一百万次,但我仍然犯了愚蠢的错误,因为我对这些错误视而不见
这次我的错误就像netBeans告诉我的那样
Exception in thread "main" java.lang.StackOverflowError
at java.awt.Insets.<init>(Insets.java:103)
at sun.awt.windows.WToolkit.getScreenInsets(Native Method)
at sun.awt.windows.WToolkit.getScreenInsets(WToolkit.java:580)
at java.awt.Window.init(Window.java:498)
at java.awt.Window.<init>(Window.java:536)
at java.awt.Frame.<init>(Frame.java:420)
at java.awt.Frame.<init>(Frame.java:385)
at javax.swing.JFrame.<init>(JFrame.java:180)
at supermarket.SuperMarket.<init>(SuperMarket.java:61)
at supermarket.SuperMarket.<init>(SuperMarket.java:132)
package supermarket;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import static javax.swing.JFrame.EXIT_ON_CLOSE;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingConstants;
public class SuperMarket extends JFrame implements ActionListener {
double juice = 1, tuna = 4, bread = 7, shampoo = 25;
double discount = 0, subTotal = 0, total = 0, d=0;
double jnum=0, tnum=0, bnum=0, snum=0;
double shN, brN, tuN, juN;
double shd, brd, tud, jud;
private JTextField shField;
private JTextField brField;
private JTextField tuField;
private JTextField juField;
private JButton cancelButton;
private JButton confirmButton;
private JTextField nmField;
private JLabel shLabel;
private JLabel brLabel;
private JLabel tuLabel;
private JLabel juLabel;
private JLabel shAmount;
private JLabel brAmount;
private JLabel tuAmount;
private JLabel juAmount;
private JPanel buttonPanel;
private JLabel shError;
private JLabel brError;
private JLabel tuError;
private JLabel juError;
private SuperMarket mainFrm;
private SuperMarket childFrm;
/**
* Create the order form.
*/
public SuperMarket() {
shLabel=new JLabel ("Shampoo Price: 25 ",SwingConstants.LEFT);
shField = new JTextField(10);
shAmount = new JLabel(shLabel+"Amount: "+shField);
try{
shd = Double.parseDouble(shField.getText());
}
catch(NumberFormatException shE){
shField.setToolTipText("You must enter integers.");
shField.setText("");
}
shN = (int) shd;
snum=shN*shampoo;
brLabel=new JLabel ("Bread Price: 7 ",SwingConstants.LEFT);
brField = new JTextField(10);
brAmount= new JLabel(brLabel+"Amount: "+brField);
try{
brd = Double.parseDouble(brField.getText());
}
catch(NumberFormatException shE){
brField.setToolTipText("You must enter integers.");
brField.setText("");
}
brN = (int) brd;
bnum=brN*bread;
tuLabel=new JLabel ("Tuna Price: 4 ",SwingConstants.LEFT);
tuField = new JTextField(10);
tuAmount = new JLabel(tuLabel+"Amount: "+tuField);
try{
tud = Double.parseDouble(tuField.getText());
}
catch(NumberFormatException shE){
tuField.setToolTipText("You must enter integers.");
tuField.setText("");
}
tuN = (int) tud;
tnum=tuN*tuna;
juLabel=new JLabel ("Juice Price: 1 ",SwingConstants.LEFT);
juField = new JTextField(10);
juAmount = new JLabel(juLabel+"Amount: "+juField);
try{
jud = Double.parseDouble(juField.getText());
}
catch(NumberFormatException shE){
juField.setToolTipText("You must enter integers.");
juField.setText("");
}
juN = (int) jud;
jnum=juN*juice;
// Order and cancel buttons
buttonPanel = new JPanel();
confirmButton = new JButton("Confirm");
buttonPanel.add(confirmButton);
cancelButton = new JButton("Cancel order");
buttonPanel.add(cancelButton);
mainFrm=new SuperMarket();
confirmButton.addActionListener(this);
cancelButton.addActionListener(this);
add(shLabel);
add(shAmount);
add(tuLabel);
add(tuAmount);
add(brLabel);
add(brAmount);
add(juLabel);
add(juAmount);
add(buttonPanel);
setVisible(true);
pack();
}
public static void main(String[] args) {
SuperMarket market=new SuperMarket();
market.setLayout(new FlowLayout());
market.setTitle("AHL Supermarket Delivery Service");
market.setSize(800, 700);
market.setDefaultCloseOperation(EXIT_ON_CLOSE);
market.setVisible(true);
}
@Override
public void actionPerformed(ActionEvent buttonEvent) {
if (buttonEvent.getSource() == confirmButton) {
childFrm=new SuperMarket();
JButton dnBtn=new JButton("Done");
childFrm.setLayout(new FlowLayout());
childFrm.setSize(200, 200);
JPanel nmPanel = new JPanel();
nmPanel.add(new JLabel("Name: "));
nmField = new JTextField(10);
nmPanel.add(nmField);
childFrm.add(nmPanel);
childFrm.add(dnBtn);
dnBtn.addActionListener(this);
childFrm.setVisible(true);
}
clearForm();
}
/**
* Clear all entries in the order form.
*/
private void clearForm() {
shField.setText("");
tuField.setText("");
juField.setText("");
}
}
我仍然没有添加输出,也没有添加总和折扣,但是当我当前的问题得到修复时,我将处理这个问题.
如果有人能帮助我,我会非常感激,因为我完全感到沮丧.
(你可以从不必要的变量数量来判断：[]
解决方法:
您正在构造函数中创建同一个类的新实例.
mainFrm=new SuperMarket();
这意味着你将再次调用构造函数,这将创建一个新实例,它将再次调用构造函数,依此类推,直到你用完“内存”(在这种情况下是堆栈空间,因此是StackOverflowError).
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