我不明白为什么我会得到例外。这是我的代码：
这是我的HealthProfile课，我有吸气剂和制定者。
public class HealthProfile {
//creating the variables
private String name;
private int age;
private double weight;
private double heightInches;
private double bmi;
// creating the constructor
public HealthProfile() {
}
// setting up the SETS
public void setName(String name1) {
this.name = name1;
}
public void setAge(int age1) {
this.age = age1;
}
public void setWeight(double weight1) {
this.weight = weight1;
}
public void setHeight(double heightFeet, double heightInches) {
this.heightInches = heightFeet * 12 + heightInches;
}
public void setBmi(double bmi) {
this.bmi = bmi;
}
// setting up the GETS
public String getName() {
return name;
}
public int getAge() {
return age;
}
public double getWeight() {
return weight;
}
public double getHeightInches() {
return heightInches;
}
public double getBMI(double BMI) {
bmi = (weight * 703) / (heightInches * heightInches);
//rounding to one decimal
return Math.round(bmi * 10.0) / 10.0;
}
// get the category
public String getCategory(double bmi) {
if (bmi < 18.5) {
return "Underweight";
} else if (bmi >= 18.5 && bmi < 25) {
return "Normal weight";
} else if (bmi >= 25 && bmi < 30) {
return "Overweight";
} else if (bmi >= 30) {
return "Obese";
} else {
return "Unknown";
}
}
//maximum heart rate
public int getMaxHR(double getMaxHr) {
return 220 - getAge();
}
}
这是我的课程JFrame：
public class HealthProfileGUI extends JFrame {
private HealthProfile hp;
private JTextField txtName;
private JTextField txtAge;
private JTextField txtWeight;
private JTextField txtHeightF;
private JTextField txtHeighti;
private JTextField txtBmi;
private JTextField txtCategory;
private JTextField txtMaxHeartRate;
private JButton btnDisplay;
private JButton btnClear;
public HealthProfileGUI() {
super("BMI Calculator");
hp = new HealthProfile();
getContentPane().setLayout(null);
// LABEL NAME
JLabel lblName = new JLabel("Name: ");
lblName.setBounds(102, 11, 46, 14);
getContentPane().add(lblName);
// LABEL AGE
JLabel lblAge = new JLabel("Age:");
lblAge.setBounds(102, 51, 46, 14);
getContentPane().add(lblAge);
// LABEL WEIGHT
JLabel lblWeight = new JLabel("Weight:");
lblWeight.setBounds(102, 96, 46, 14);
getContentPane().add(lblWeight);
// LBL HEIGHT FEET
JLabel lblHeightfeet = new JLabel("Height-feet:");
lblHeightfeet.setBounds(102, 147, 83, 14);
getContentPane().add(lblHeightfeet);
// LABEL BMI
JLabel lblBmi = new JLabel("BMI:");
lblBmi.setBounds(102, 319, 46, 14);
getContentPane().add(lblBmi);
// LABEL CATEGORY
JLabel lblCategory = new JLabel("Category:");
lblCategory.setBounds(102, 368, 66, 14);
getContentPane().add(lblCategory);
// LABEL MAX HEART RATE
JLabel lblMaxHeartRate = new JLabel("Max Heart Rate:");
lblMaxHeartRate.setBounds(102, 418, 93, 14);
getContentPane().add(lblMaxHeartRate);
// LABEL HEIGHT INCHES
JLabel lblHeightInches = new JLabel("Height-Inches:");
lblHeightInches.setBounds(102, 195, 83, 14);
getContentPane().add(lblHeightInches);
// TEXT NAME
txtName = new JTextField();
txtName.setBounds(203, 8, 164, 20);
getContentPane().add(txtName);
txtName.setColumns(10);
// TEXT AGE
txtAge = new JTextField();
txtAge.setBounds(203, 48, 164, 20);
getContentPane().add(txtAge);
txtAge.setColumns(10);
// TEXT HEIGHT FEET
txtHeightF = new JTextField();
txtHeightF.setBounds(203, 144, 164, 20);
getContentPane().add(txtHeightF);
txtHeightF.setColumns(10);
// TEXT BMI
txtBmi = new JTextField();
txtBmi.setBounds(199, 316, 168, 20);
getContentPane().add(txtBmi);
txtBmi.setColumns(10);
// TEXT CATEGORY
txtCategory = new JTextField();
txtCategory.setBounds(199, 365, 168, 20);
getContentPane().add(txtCategory);
txtCategory.setColumns(10);
// TEXT HEART RATE
txtMaxHeartRate = new JTextField();
txtMaxHeartRate.setBounds(199, 415, 168, 20);
getContentPane().add(txtMaxHeartRate);
txtMaxHeartRate.setColumns(10);
// TEXT WEIGHT
txtWeight = new JTextField();
txtWeight.setBounds(203, 93, 164, 20);
getContentPane().add(txtWeight);
txtWeight.setColumns(10);
// TEXT HEIGHT INCHES
txtHeighti = new JTextField();
txtHeighti.setBounds(203, 192, 164, 20);
getContentPane().add(txtHeighti);
txtHeighti.setColumns(10);
// BUTTON DISPLAY
btnDisplay = new JButton("Display");
btnDisplay.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
hp.setName(txtName.getText());
hp.setAge(Integer.parseInt(txtAge.getText()));
hp.setWeight(Double.parseDouble(txtWeight.getText()));
hp.setHeight(Double.parseDouble(txtHeightF.getText()),
Double.parseDouble(txtHeighti.getText()));
hp.getBMI(Double.parseDouble(txtBmi.getText()));
hp.getCategory(Double.parseDouble(txtCategory.getText()));
hp.getMaxHR(Double.parseDouble(txtMaxHeartRate.getText()));
if (txtName.equals("")) {
JOptionPane.showMessageDialog(null, "Name cannot be blank!");
}
else if (txtAge.equals("")) {
JOptionPane.showMessageDialog(null, "Age cannot be blank!");
}
else if (txtWeight.equals("")) {
JOptionPane.showMessageDialog(null, "Weight cannot be blank!");
}
else if (txtHeightF.equals("")) {
JOptionPane.showMessageDialog(null, "Height cannot be blank!");
}
else if (txtHeighti.equals("")) {
JOptionPane.showMessageDialog(null, "Height cannot be blank!");
}
}
});
btnDisplay.setBounds(59, 250, 148, 31);
getContentPane().add(btnDisplay);
// BUTTON CLEAR
btnClear = new JButton("Clear");
btnClear.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
txtName.setText("");
txtAge.setText("");
txtWeight.setText("");
txtHeightF.setText("");
txtHeighti.setText("");
txtBmi.setText("");
txtCategory.setText("");
txtMaxHeartRate.setText("");
}
});
btnClear.setBounds(251, 250, 148, 31);
getContentPane().add(btnClear);
}
}
以下是我得到的例外情况：
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 com.samhorga.week2.HealthProfileGUI$1.actionPerformed(HealthProfileGUI.java:131)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
答案 0 :(得分：1)
在butnDisplay的actionPerformed方法中，你有：
btnDisplay.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
hp.setName(txtName.getText());
hp.setAge(Integer.parseInt(txtAge.getText()));
您看到的异常是因为调用Integer.parseInt（）并将空字符串作为参数。只有在那次通话之后，你才检查txtAge是否等于＆＃34;＆＃34;。
因此，请将hp.setAge（）等调用移至检查后的点（当然，对于每个错误情况，您都需要返回＆＃39;）