将双精度转换为2位小数

Question

I got a table column with decimal(18,2) data type as price in database. When I create a product, let's say I enter $15.50, it's stored as 15.50 in database. But however, when I try to retrieve the value from database as Double and display in table, it shows 15.5. This is how I set up my price in table:

 TableColumn prodPriceCol = new TableColumn("PRICE ($)");
 prodPriceCol.setCellValueFactory(new PropertyValueFactory<Product, Double>("prodPrice"));
 prodPriceCol.setMinWidth(100);

Then inside my product class:

private SimpleDoubleProperty prodPrice;

 public void setprodPrice(double value) {
    prodPriceProperty().set(value);
}

public Double getprodPrice() {
    return prodPriceProperty().get();
}

public SimpleDoubleProperty prodPriceProperty() {
    if (prodPrice == null) {
        prodPrice = new SimpleDoubleProperty(this, "prodPrice");
    }
    return prodPrice;
}

And my SQL:

String sql = "SELECT * FROM sm_product WHERE productCategory = '" + category + "'";
        ResultSet rs = null;
        // Call readRequest to get the result
        rs = db.readRequest(sql);

        while (rs.next()) {
            String ID = rs.getString("productID");
            String name = rs.getString("productName");
            String desc = rs.getString("productDescription");
            double price = rs.getDouble("productPrice");

By the way I am doing it in JavaFX.

Answer 1

Format your double value to formated string using DecimalFormat .

String priceString = new DecimalFormat("$##.##").format(price);

Output -

$15.50

Answer 2

You can format by using BigDecimal :

double value= 255.956666;

BigDecimal bd = new BigDecimal(value).setScale(2, RoundingMode.HALF_UP);
System.out.println("value=" + bd);

Answer 3

I would suggest, get the value in the form of String.

String price = rs.getString("productPrice");

And where-ever you need to display the result display the string and for the calculation part convert it into Double and then use it.

Answer 4

You can format the price using NumberFormat :

  NumberFormat nf = new NumberFormat() ;
    nf.setMaximumFractionDigits(2) 
    nf.setMinimumFractionDigits(2)  


        nf.format(ton_double)
         while (rs.next()) {
                    String ID = rs.getString("productID");
                    String name = rs.getString("productName");
                    String desc = rs.getString("productDescription");
            double priceNF = rs.getDouble("productPrice");

                    double price = Double.valueOf(nf.format(priceNf));
        }

Answer 5

You shouldn't store your values as Double s. BigDecimal is the standard type for monetary values.