Java集合的接口和类层次结构图以及代码示例

男娘i 2022-05-24 00:41 156阅读 0赞

### 1. Collection vs Collections ###

首先，“Collection”和“Collections”是两个不同的概念。正如你从下面结构图看到的，“Collection”是集合层次结构中的根接口，而“Collections”是一个类，它提供了一系列静态方法来操作集合。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzODczNDMx_size_16_color_FFFFFF_t_70][]

### 2. Collection层次结构 ###

下图展示了Collection的类层次结构。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzODczNDMx_size_16_color_FFFFFF_t_70 1][]

### 3.Map层次结构 ###

以下是Map的类层次结构。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzODczNDMx_size_16_color_FFFFFF_t_70 2][]

### 4.总结 ###

![2019040911302645.png][]

### 5.代码示例 ###

下面是一个简单的例子来说明一些集合类型：

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);

输出：

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\}

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzODczNDMx_size_16_color_FFFFFF_t_70 1]: /images/20220524/f5c1ef29e9ca48d8804749b48edd2ab3.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzODczNDMx_size_16_color_FFFFFF_t_70 2]: /images/20220524/a4bc1c6437304418b225eb1b7a4f40ed.png
[2019040911302645.png]: /images/20220524/707598c79bbc484289dc5aeb7513cecf.png