java中集合的详细讲解(总结篇)

java中的集合有List，Set,Map之前一直混淆，尤其是遍历方法容易牛头不对马嘴，所以今天花点时间好好整理下：

本文只介绍ArrayList，HashSet，TreeSet,HashMap,TreeMap的添加和遍历,队列Queue和栈Stack的基本使用

List:

        List list = Arrays.asList("一","二","三","八","五","六","零","一");
        Iterator iterator = list.iterator();
        while(iterator.hasNext()){                       //使用迭代器遍历
            System.out.println(iterator.next());
        }
        for (String l:                         //for循环
                list) {
            System.out.println(l);
        }
        System.out.println(list.get(5));
        System.out.println(list.lastIndexOf("一"));
        ListIterator stringListIterator = list.listIterator(4);
        Spliterator spliterator = list.spliterator();//分迭代器
//        spliterator.forEachRemaining(lang -> System.out.println(lang));
        List strings = list.subList(2, 6);    //输出list中从下标2到6的元素

        for (String s : strings){
            System.out.println(s);
        }

HashSet的使用：Set hashset = new HashSet<>();
hashset.add("小二");
hashset.add("大二");
hashset.add("小二");
hashset.add("六");
hashset.add("炸");
Set humanSet =  new HashSet<>();
humanSet.add(new Human("1","2"));
humanSet.add(new Human("3","4"));
humanSet.add(new Human("5","6"));
Human[] s = humanSet.toArray();
Iterator iterator = hashset.iterator();
while(iterator.hasNext()){
    System.out.println(iterator.next());
}
Spliterator spliterator = hashset.spliterator();
spliterator.forEachRemaining(s -> System.out.println(s));

TreeSet的使用：Set treeHuman = new TreeSet<>(new Comparator() {
    @Override
    public int compare(Human o1, Human o2) {
        return -1;
    }
});
treeHuman.add(new Human("1","2"));
treeHuman.add(new Human("3","4"));
treeHuman.add(new Human("5","6"));
Iterator iterator = treeHuman.iterator();
while (iterator.hasNext()) {
    System.out.println(iterator.next());
}

Map之HashMap的使用：Map,String> hashMap = new TreeMap<>();
hashMap.put("123","qwe");
hashMap.put("234","asd");
hashMap.put("345","zxc");
Iterator, String>> iterator = hashMap.entrySet().iterator();//迭代器
while (iterator.hasNext()) {
    Map.Entry, String> next = iterator.next();
    String s1 = next.getKey();
    String s2 = next.getValue();
    System.out.println(s1+" "+s2);
}
Object[] objects = hashMap.entrySet().toArray();//数组
for (int i = 0 ; i < objects.length;i++){
    Map.Entry object = (Map.Entry) objects[i];
    Object key = object.getKey();
    Object value = object.getValue();

TreeMap的使用：

Map,Integer> treeMap = new TreeMap<>();
treeMap.put("123",1);
treeMap.put("234",2);
treeMap.put("345",3);
treeMap.put("456",4);
Set strings = treeMap.keySet();
Iterator iterator = strings.iterator();
while (iterator.hasNext()) {
    int s = treeMap.get(iterator.next());
    System.out.println(s);
}

    System.out.println(key+" " +value);
}

队列Queue和栈Stack的讲解:

package sample.org.jasen.TestQueueAndStack;

import java.util.LinkedList;
import java.util.Queue;
import java.util.Stack;



 class TestQueueAndStack {

        
        static void testQueue(){
            Queue queue=new LinkedList();
            //添加几个元素
            queue.offer("a");
            queue.offer("b");
            queue.offer("c");
            queue.offer("d");
            queue.offer("e");
            queue.add("1");
            queue.add("2");
            queue.add("3");
            queue.add("4");
            queue.add("5");
            System.out.println("队列中的元素是:"+queue);
            //弹出元素
            queue.poll();
            System.out.println("队列中的元素是:"+queue);
            //查看队列中首个元素，并不移除
            String peek=queue.peek();
            System.out.println("查看队列中首个元素，并不移除:"+peek);
            System.out.println("队列中的元素是:"+queue);
        }


        
        static void testStack(){
            Stack stack=new Stack();
            //添加几个元素
            stack.push("a");
            stack.push("b");
            stack.push("c");
            stack.push("d");
            stack.push("e");
            stack.add("1");
            stack.add("2");
            stack.add("3");
            stack.add("4");
            stack.add("5");
            System.out.println("栈中的元素是:"+stack);
            //弹出元素
            stack.pop();
            System.out.println("栈中的元素是:"+stack);
            //查看栈中首个元素，并不移除
            String peek=stack.peek();
            System.out.println("查看栈中首个元素，并不移除:"+peek);
            System.out.println("栈中的元素是:"+stack);
        }


        
        public static void main(String[] args) {
            testQueue();
            System.out.println("-------栈--------");
            testStack();
        }

    }