【Java】【集合框架】集合框架（list）

集合框架（list）

1. ArrayList（数组集合）查询与修改快

迭代器
@SuppressWarnings({ "rawtypes", "unchecked" })
public class Demo1_Collection {

    public static void main(String[] args) {
        ArrayList<Student> list = new ArrayList<>();
        list.add(new Student("张三", 23));
        list.add(new Student("李四", 24));
        list.add(new Student("王五", 25));
    
        Iterator<Student> iterator = list.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next());
        }
        
    }
}

2. 迭代器并发修改异常解决方案

@SuppressWarnings({ "rawtypes", "unchecked" })
public class Demo1_Collection {

    public static void main(String[] args) {
        ArrayList list = new ArrayList();
        list.add("a");
        list.add("b");
        list.add("c");
    
        ListIterator listIterator = list.listIterator();
        while(listIterator.hasNext()){
            String string = (String)listIterator.next();
            if("c".equals(string)){
                listIterator.add("JavaEE");
            }
        }
        System.out.println(list);
    }
}

3. LinkedList 增删快

@SuppressWarnings({ "rawtypes", "unchecked" })
public class Demo1_Collection {

    public static void main(String[] args) {
        LinkedList list = new LinkedList();
        list.add("a");
        list.add("b");
        list.add("c");
    
        ListIterator listIterator = list.listIterator();
        while(listIterator.hasNext()){
            String string = (String)listIterator.next();
            if("c".equals(string)){
                listIterator.add("JavaEE");
            }
        }
        System.out.println(list);
    }
}

4. ArrayList去除重复内容 当我们重写数据模型equals方法后也可以通过这种方式去重引用类型内容

@SuppressWarnings({ "rawtypes", "unchecked" })
public class Demo1_Collection {

    public static void main(String[] args) {
        ArrayList list = new ArrayList();
        list.add("a");
        list.add("b");
        list.add("b");
        list.add("c");
        list.add("c");
        list.add("b");
        list.add("b");
        list.add("a");
        System.out.println(getSingle(list));
    }

    public static ArrayList getSingle(ArrayList list) {
        ArrayList newList = new ArrayList<>();
        Iterator it = list.iterator();
    
        while (it.hasNext()) {
            Object obj = (Object)it.next();
            if (!newList.contains(obj)) {
                newList.add(obj);
            }
        }
    
        return newList;
    }
}