import org.apache.commons.lang.StringUtils;
public class Test {
public static void main(String[] args){
String[] str = {"a","b","c","d","e"};
String join = StringUtils.join(str, ",");
System.out.println(join); //a,b,c,d,e
String str2 = String.format("%s,%s,%s", str);
System.out.println(str2); //a,b,c
List<String> errClassList = Arrays.asList("a","a","a","a");
String join1 = StringUtils.join(errClassList, ",");
System.out.println(join1);//a,a,a,a
}
}