Java 检查字段是否为空，然后使用0值自动填充

因此，我尝试在这里添加，它将发现如果留空并自动填充0。我尝试了if.empty语句，但无法使其工作。我想我可以改变getText.equals，但似乎我还有问题，你们能帮我吗？有什么建议吗？多谢各位

私有void jButton23ActionPerformedjava.awt.event.ActionEvent evt{

double lab=Double.parseDouble(jTextField2.getText());
double tav=Double.parseDouble(jTextField3.getText());
double cle=Double.parseDouble(jTextField4.getText());
double wal=Double.parseDouble(jTextField5.getText());         
double has=Double.parseDouble(jTextField11.getText());



double r,v,m,i,x,total;



if(!(jCheckBox1.isSelected()) && (!(jCheckBox2.isSelected())))
{
   jTextField1.setText(" Calculations Here");
   jTextField2.setText("");
   jTextField3.setText("");
   jTextField4.setText("");
   jTextField5.setText("");
   jTextField6.setText("");
   jTextField7.setText("");
   jTextField15.setText("");
   jTextField16.setText("");
   jTextField17.setText("");
   jTextField11.setText("");
   
    
}

if(jCheckBox3.isSelected())
{
    r=((lab*labour)+(tav*travel)+(cle*clean));
    String end_r;
    end_r = String.format("%.2f", r);
    jTextField17.setText(end_r);
    
    v=(lab*labour);
    m=(tav*travel);
    i=((cle*clean)+(wal*walk)+(has*hassle));
    
    String job=String.format("%.2f", v);
    String miles=String.format("%.2f", m);
    String manual=String.format("%.2f", i);
    
    jTextField6.setText(manual);
    jTextField7.setText(miles);
    jTextField12.setText(job);
    
}

if(jCheckBox4.isSelected())
{
    r=((lab*labour)+(tav*travel)+(cle*clean));
    String end_r;
    end_r = String.format("%.2f", r);
    jTextField17.setText(end_r);
    
    v=(lab*labour);
    m=(tav*travel);
    i=((cle*clean)+(wal*walk)+(has*hassle));
    
    String job=String.format("%.2f", v);
    String miles=String.format("%.2f", m);
    String manual=String.format("%.2f", i);
    
    jTextField6.setText(manual);
    jTextField7.setText(miles);
    jTextField12.setText(job);
    
}

if(jCheckBox6.isSelected())
{
    r=((lab*labour)+(tav*travel)+(cle*clean));
    String end_r;
    end_r = String.format("%.2f", r);
    jTextField17.setText(end_r);
    
    v=(lab*labour);
    m=(tav*travel);
    i=((cle*clean)+(wal*walk)+(has*hassle));
    
    String job=String.format("%.2f", v);
    String miles=String.format("%.2f", m);
    String manual=String.format("%.2f", i);
    
    jTextField6.setText(manual);
    jTextField7.setText(miles);
    jTextField12.setText(job);
    
}