Set转逗号分隔字符串

rg.apache.commons.lang.StringUtils中的join方法可以将数组转化为字符串

Set转字符串，先将Set转数组，然后数组转字符串

@Test
public void run5() {
    Set<String> set = new HashSet<String>();
    set.add("lingq");
    set.add("dengp");
    set.add("liuw1");
    System.out.println(set);
    Object[] array = set.toArray();
    String splitSet = StringUtils.join(array);
    System.out.println("splitSet:" + splitSet);
    String splitSetWithComma = StringUtils.join(array, ",");
    System.out.println("splitSetWithComma:" + splitSetWithComma);
}