Java 嵌套方法中的while循环后无法返回值

我在添加第二个while循环后返回DVDs对象时遇到问题。此函数在添加while循环之前工作得非常好。编译期间出错-找不到符号：变量currentDVD

public DVDs getNewDVDInfo() {
    boolean keepRunning = true;
    boolean promptAddAgain = true;
    while (keepRunning) {
        String title = input.readString("Please enter the move title.");
        String releaseDate = input.readString("Please enter the release date.");
        String MPAArating = input.readString("Please enter the MPAA rating.");
        String directorName = input.readString("Please enter the director name.");
        String studio = input.readString("Please enter the name of the studio.");
        String userRating = input.readString("Please type in any comment you would "
                + "like to leave for this movie below.");

        DVDs currentDVD = new DVDs(releaseDate, MPAArating, directorName, studio, userRating);
        currentDVD.setTitle(title);

        while (promptAddAgain) {
            String userAns = input.readString("Would you like to add another DVD to the library?");
            if (userAns.equals("n")) {
                input.print("Thank you.  Returning to main menu.");
                keepRunning = false;
                promptAddAgain = false;
            } else if (userAns.equals("y")) {
                input.print("\n");
            } else {
                input.print("Unknown input, please try again.");
                keepRunning = false;
            }
        }
    }
    return currentDVD; //<--- error
}

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出现错误的原因是currentDVD当前是在外部while循环内定义的，但在它超出范围后，您在该循环外引用它。解决此问题的一种方法是在第一个while循环之前声明currentDVD：

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请记住，使用上述方法，您的getNewDVDInfo方法可能会返回null，因此调用者应该知道这一点。

解决了这个问题。没有注意到那里的范围。谢谢当然，就是这样；

DVDs currentDVD = null;
while (keepRunning) {
    ...
}
return currentDVD;