将Java框中的消息头更改为；如果；及；否则"；

如果有多个字符串和整数一起工作，如何更改showMessageDialog中的消息头

这就是我如何让它工作的方法：

showMessageDialog (null, "string", "where I change the name of the box", INFORMATION_MESSAGE);

if (price >= 300) {
    deduction = price * 0.10;
    price = price - deduction;

    showMessageDialog (null, "Total price: ", 
                "where I want to change the        name", INFORMATION_MESSAGE 
                + price + " ." + " Received deduction: " + deduction);

这是我无法让它工作的地方：

showMessageDialog (null, "string", "where I change the name of the box", INFORMATION_MESSAGE);

if (price >= 300) {
    deduction = price * 0.10;
    price = price - deduction;

    showMessageDialog (null, "Total price: ", 
                "where I want to change the        name", INFORMATION_MESSAGE 
                + price + " ." + " Received deduction: " + deduction);

Eclipse给出以下错误消息：

中的方法showMessageDialog（组件、对象、字符串、int） 类型JOptionPane不适用于参数（null、String、， String，String）“并建议我创建方法showMessageDialog （对象，字符串，字符串，字符串）

---

有什么建议吗？：）

信息\u消息是定义消息类型的常量。请尝试使用以下方法：

showMessageDialog(null, "Total price: ", price + " ." + " Received deduction: " + deduction, INFORMATION_MESSAGE);

---

我不能说我真的理解这个问题，尽管试试看

showMessageDialog (null, "Total price: " + 
    + price + " ." + " Received deduction: " + deduction,
    "where I want to change the name", INFORMATION_MESSAGE);