幾幅圖讓你認識Java集合
1.Collection 和 Collections
首先Collection和Collections是兩個完全不同的範疇。正如下圖,Collection是所有集合的root接口,而Collections僅僅是一個工具類,它提供了很多靜態的工具方法來操作一個集合。

2. 集合的繼承樹

3.Map的繼承樹

4.總結

5.示例代碼
Code:
List<String> a1 = new ArrayList<String>(); a1.add("Program"); a1.add("Creek"); a1.add("Java"); a1.add("Java");System.out.println("ArrayList Elements");System.out.print("\t" + a1 + "\n"); List<String> l1 = new LinkedList<String>(); l1.add("Program"); l1.add("Creek"); l1.add("Java"); l1.add("Java");System.out.println("LinkedList Elements");System.out.print("\t" + l1 + "\n"); Set<String> s1 = new HashSet<String>(); // or new TreeSet() will order the elements; s1.add("Program"); s1.add("Creek"); s1.add("Java"); s1.add("Java"); s1.add("tutorial");System.out.println("Set Elements");System.out.print("\t" + s1 + "\n"); Map<String, String> m1 = new HashMap<String, String>(); // or new TreeMap() will order based on keys m1.put("Windows", "2000"); m1.put("Windows", "XP"); m1.put("Language", "Java"); m1.put("Website", "programcreek.com");System.out.println("Map Elements");System.out.print("\t" + m1);Output:
ArrayList Elements [Program, Creek, Java, Java] LinkedList Elements [Program, Creek, Java, Java] Set Elements [tutorial, Creek, Program, Java] Map Elements {Windows=XP, Website=programcreek.com, Language=Java}
最後更新:2017-04-03 05:40:12