元素遍历以逗号拼接
原生遍历写法
//通过遍历列表拼接获取 ids
public static void main(String[] args) {
//方式一
ArrayList<Integer> idList = Lists.newArrayList(1, 2, 3, 4);
//方式二
// ArrayList idList = new ArrayList();
// idList.add(1);
// idList.add(2);
// idList.add(3);
// idList.add(4);
System.out.println("打印初始列表为:" + idList);
StringBuffer stringBuffer = new StringBuffer();
for (Object e : idList) {
stringBuffer.append(e).append(",");
}
String str = stringBuffer.toString();
str = str.substring(0, str.length() - 1);
System.out.printf("最终输出结果为:" + str);
}
StringUtils写法
//通过StringUtils.join(idList.toArray(), ",")更方便
public static void main() {
ArrayList<Integer> idList = Lists.newArrayList(1,2,3,4,5);
System.out.println("打印初始列表为:" + idList);
// 一行代码就可以 import org.apache.commons.lang.StringUtils注意包别导错
String ids = StringUtils.join(idList.toArray(), ",");
System.out.printf("最终输出结果为:" + ids);
}