方法重复输出 [英] Method duplicates output

问题描述

对 sling 和 Java 非常陌生，所以我提前道歉.但是有没有人知道为什么当我在根时它正在输出我的路径两次?奇怪的是它只发生在绝对根处.

Pretty new to sling and Java so I apologize in advance. But does anybody have any idea why when I'm at the root it's outputting my path twice? It's odd that it only happens at the absolute root.

public static String generateTest(Page page, Page rootPage, String bc) {

    Page parent = page.getParent();

    String bread = ""; 
    bread += (parent != null) ? "<li><a href=" + parent.getPath() + ">" + parent.getTitle() + "</a>" : "";
    bread += "<li>" + "<a href=" + page.getPath() + ">" + page.getTitle() + "</a></li>" + bc;
    return (ifAtRoot(parent , rootPage)) ? breadcrumb : generateTest(parent, rootPage, bread);

}

public static boolean ifAtRoot(Page page, Page root) {
    return (page == null || root.getPath() == page.getPath());
}

非常感谢任何帮助！

推荐答案

首先，ifAtRoot() 只会在 page 为 null 时返回 true> 因为您不能使用 == 比较对象(包括字符串).您应该使用 .equals() 代替:

First, ifAtRoot() will return true only if page is null because you cannot compare objects (including strings) using ==. You should use .equals() instead:

public static boolean ifAtRoot(Page page, Page root) {
    return (page == null || root.getPath().equals(page.getPath()));
}

在您的情况下，第一次调用 ifAtRoot() 返回 false，因此您第二次调用它递归传递刚刚创建的 brend.第二个调用再次创建 brend 并将 bc(包含先前创建的 brend)附加到它.ifAtRoot() 的第二次调用返回true.否则，您将进入无限递归并以 StackOverflowError 结束.

In your case first call of ifAtRoot() returned false, so you called it second time recursively passing brend that just has been created. The second call creates brend again and appends bc (that contains previously created brend) to it. The second call of ifAtRoot() for your luck returns true. Otherwise you'd enter infinite recursion and finish with StackOverflowError.

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