java - for 循环内的 if else 语句与 Hashmap 相关

Question

基本上，我的 if 语句遇到了问题。我想说“没有找到” + val 的 CD，但是这是我得到的输出:

    Welcome to the CD Database
    Enter search, add, name, list, or quit:
    name
    Enter the full or partial name:
    asdfa
    Enter search, add, name, list, or quit:

如您所见，它没有返回任何内容。

我的代码:

public void printByName(String val) {

    int i = 0;
    for (CompactDisc values : database.values()) {

        if (values.getArtist().contains(val)) {

            System.out.println(values);

        } else if (i > database.size() && !values.getArtist().contains(val)) {

            System.out.println("No CDs found for " + val);

        }

       i++; 
}
}

由于某种原因，我的计数器没有迭代，这让我发疯了好几个小时。我希望它在循环遍历 HashMap 后没有找到 CD，并且没有找到用户输入的字符串的部分匹配

附加输出:

Welcome to the CD Database
Enter search, add, name, list, or quit:
name
Enter the full or partial name:
Mo
Artist:Modest Mouse Title:We Were Dead Before the Ship Even Sank price:5.99
Artist:Thelonious Monk Title:Monk's Dream price:5.99
Enter search, add, name, list, or quit:
list
Artist:Isley Brothers Title:Funky Family price:5.99
Artist:Muddy Waters Title:At Newport price:6.99
Artist:Sly & The Family Stone Title:Greatest Hits price:6.99
Artist:Modest Mouse Title:We Were Dead Before the Ship Even Sank price:5.99
Artist:St. Germain Title:Tourist price:5.99
Artist:Bob Dylan Title:Desire price:6.99
Artist:The Beatles Title:Abbey Road price:6.99
Artist:Los Straitjackets Title:The Velvet Touch of... price:5.99
Artist:The Velvet Underground Title:Peel Slowly and See price:6.99
Artist:Thelonious Monk Title:Monk's Dream price:5.99
Enter search, add, name, list, or quit:
quit
Program ending.

Answer 1

条件i > database.size()永远不会为真，因为循环将在i达到数据库大小之前退出。尝试将您的代码更改为:

public void printByName(String val) {
    for (CompactDisc values : database.values()) {
        if (values.getArtist().contains(val)) {
            System.out.println(values);
        } else {
            System.out.println("No CDs found for " + val);
        }

    }
}