java字符串与集合转换工具使用
我们知道在Java 中有几种集合类,比如 List,Set,还有 Map,List集合一般是存放的元素是有序可重复的,Set 存放的元素则是无序不可重复的,而 Map 集合存放的是键值对。
/**
* 将字符串转换为集合
* @param string
* @return
*/
private static List<String> getList(String string) {
String[] split = string.split(",");
List<String> strings = Arrays.asList(split);
return strings;
}
我们知道集合中有个上层接口 List,其有个典型实现类 ArrayList
public class ArrayList<E> extends AbstractList<E>
implements List<E>, RandomAccess, Cloneable, java.io.Serializable
所以我们可以用 instanceof 运算符判断 某个对象是否是 List 接口的实现类,如果是返回 true,否则返回 false
ArrayList arrayList = new ArrayList();
System.out.println(arrayList instanceof List);//true
java判断数组中是否包含某个元素
String[] orgString = {"2018-01","2018-02","2018-03","2018-04","2018-05","2018-06","2018-07","2018-08","2018-09","2018-10","2018-11","2018-12"};
for (LeakPointVO leakPointVO : realRushCount) {
String counts = leakPointVO.getNormalValue();
String checkDate = leakPointVO.getCheckDate();
if(!Arrays.asList(orgString).contains(checkDate)||null==checkDate) {
continue;
}
String checkDateName = compareDic(checkDate);
datelist.add(checkDateName);
Numlist.add(counts);
}