// Collections,工具类 public static void main(String[] args) { List<Integer> list = new ArrayList<Integer>(); // Collections,为List增加内容 Collections.addAll(list, 10, 1, 2, 34, 5, 6, 653, 211, 23); Iterator<Integer> iterator = list.iterator(); while (iterator.hasNext()) { Integer integer = iterator.next(); System.out.print(integer + "."); } System.out.println("=============================="); Collections.reverse(list);// 反转内容 Iterator<Integer> iterator2 = list.iterator(); while (iterator2.hasNext()) { Integer integer = iterator2.next(); System.out.print(integer + "."); } System.out.println("=============================="); // 检索内容,输出位置 int i = Collections.binarySearch(list, 5); System.out.println("位置在: " + i); System.out.println("=============================="); //替换内容 if (Collections.replaceAll(list, 23, 30)) { System.out.println("替换成功"); } System.out.println("=============================="); //排序 //要求排序的对象实现了Comparable接口 List<String> arrayList = new ArrayList<String>(); Collections.addAll(arrayList, "123","qwe","asd","34"); Collections.addAll(arrayList, "we"); Collections.addAll(arrayList, "看看","不小心"); Collections.sort(arrayList); Iterator<String> iterator3 = arrayList.iterator(); while(iterator3.hasNext()){ String next = iterator3.next(); System.out.print(next+"."); } System.out.println("=============================="); //交换指定位置的元素 List<Integer> arrayList2 = new ArrayList<Integer>(); Collections.addAll(arrayList2, 1,2,3); Collections.swap(arrayList2, 0, 2);//交换位置1和位置3的 Iterator<Integer> iterator4 = arrayList2.iterator(); while (iterator4.hasNext()) { Integer next = iterator4.next(); System.out.print(next+" "); }
Java.Collections,工具类
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