如何在for-each循环中的每个元素之间添加分隔符？

List<String> list = Arrays.asList("元素1", "元素2", "元素3", "元素4");
String separator = ", ";
boolean isFirst = true;

for (String element : list) {
    if (isFirst) {
        isFirst = false;
    } else {
        System.out.print(separator);
    }
    System.out.print(element);
}

List<String> list = Arrays.asList("元素1", "元素2", "元素3", "元素4");
String separator = ", ";
StringBuilder result = new StringBuilder();

for (String element : list) {
    result.append(element).append(separator);
}

if (result.length() > 0) {
    result.setLength(result.length() - separator.length());
}

System.out.println(result.toString());