在一次做项目的过程中要遍历 list 集合,然后根据条件删除 list 集合中不需要的对象,尝试了 list.remove() 方法,根本达不到目的,最后在网上看了几个帖子后才知道,要想根据条件删除 list 集合里面的对象,一定要使用 Iterator 遍历删除
如下示例
public class ListDemo {
public static void main(String[] args) {
List<Fruit> fruitList = new ArrayList<>();
fruitList.add(new Fruit(1, "apple", "红色", 120.00));
fruitList.add(new Fruit(2, "orange", "黄色", 140.00));
fruitList.add(new Fruit(3, "guava", "灰色", 160.00));
fruitList.add(new Fruit(4, "pear", "黄色", 180.00));
fruitList.add(new Fruit(5, "mango", "黄色", 240.00));
fruitList.add(new Fruit(6, "watermelon", "绿色", 260.00));
if (Objects.nonNull(fruitList) && !fruitList.isEmpty()) {
for (Fruit fruit : fruitList) {
if (Objects.equals(fruit.getColor(), "黄色")) {
fruitList.remove(fruit);
}
}
}
}
}
执行上面的代码时会出现如下报错
对于 List 集合来说,如果你想移除 List 集合中的元素,必须要使用 Iterator 进行迭代遍历
public class ListDemo {
public static void main(String[] args) {
List<Fruit> fruitList = new ArrayList<>();
fruitList.add(new Fruit(1, "apple", "红色", 120.00));
fruitList.add(new Fruit(2, "orange", "黄色", 140.00));
fruitList.add(new Fruit(3, "guava", "灰色", 160.00));
fruitList.add(new Fruit(4, "pear", "黄色", 180.00));
fruitList.add(new Fruit(5, "mango", "黄色", 240.00));
fruitList.add(new Fruit(6, "watermelon", "绿色", 260.00));
if (Objects.nonNull(fruitList) && !fruitList.isEmpty()) {
ListIterator<Fruit> iterator = fruitList.listIterator();
while(iterator.hasNext()){
// 注意,进行元素移除的时候只能出现一次 iterator.next()
if(Objects.equals(iterator.next().getColor(),"黄色")){
iterator.remove();
}
}
}
}
}