Java：如何通过jcombo列表获取表达式

Question

How do i create the one line expression using Java swing, link image picture . the every minute, every day,every month, every weekday and every hour need to convert it to "*" and also all the combo box contain the list of number list number link and weekday contain the click the picture

what i want is, if the user select "Every Minute" , "Every day","month = 2", "Weekday = monday", "hour= 3"

note of weekday JCombo : sunday = 0 , monday = 1, tuesday = 2 .....

the output will print as : * * 2 1 3

thanks alot.

i already tried this , my beginning code but cant do much :

String sjcb_EM = jcb_EM.getSelectedItem().toString();
    String sjcb_EH = jcb_EH.getSelectedItem().toString();
    String sjcb_ED = jcb_ED.getSelectedItem().toString();
    String sjcb_EEM = jcb_EEM.getSelectedItem().toString();
    String sjcb_EW = jcb_EW.getSelectedItem().toString();

    String vb_1 = sjcb_EM + " " + sjcb_EH + " " + sjcb_ED + " " + sjcb_EEM + " " + sjcb_EW;

System.out.println(vb_1);

now i stuck, how to make the expression that i wanted.

Answer 1

Start by building a class which can hold both the display value and the query value...

public class WorkoutUnit {
    private String displayValue;
    private String queryValue;

    public WorkoutUnit(String displayValue, String queryValue) {
        this.displayValue = displayValue;
        this.queryValue = queryValue;
    }

    public String getDisplayValue() {
        return displayValue;
    }

    public String getQueryValue() {
        return queryValue;
    }

    @Override
    public String toString() {
        return displayValue;
    }
}

Build a ComboBoxModel using these values...

DefaultComboBoxModel<WorkoutUnit> model = new DefaultComboBoxModel<>();
model.addElement(new WorkoutUnit("Every Minute", "*"));
for (int index = 10; index < 61; index += 10) {
    model.addElement(new WorkoutUnit(Integer.toString(index), Integer.toString(index)));
}
JComboBox<WorkoutUnit> cb = new JComboBox(model);

When needed, get the selected item from the combo box and get its query value...

WorkoutUnit unit = (WorkoutUnit)cb.getSelectedItem();
System.out.println("Query = " + unit.getQueryValue());

In this example, I've used toString to provide the display value to the JComboBox , this is not my preferred solution, I'd prefer to use a ListCellRenderer as demonstrated here

Oh, and because it looks like you're heading down a database query route, you should also have a look at Using Prepared Statements