集合類接口和類層次關係圖

1. Collection vs Collections

首先,「Collection」和「Collections」是兩個不一樣的概念。你能夠從下面的層次關係圖中看到,」Collection」是集合層次的頂層接口,而」Collections」是提供了操做集合類型的靜態方法的類。java

2. 集合類層次關係圖

下圖是集合類的層次關係圖git

3. Map的類層次結構關係圖

下圖是Map的類層次結構關係圖github

4. 集合類總結

5. 代碼示例

下面是一個簡單的集合的例子:spa

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List a1 = new ArrayList();
a1.add( "Program" );
a1.add( "Creek" );
a1.add( "Java" );
a1.add( "Java" );
System.out.println( "ArrayList Elements" );
System.out.print( "\t" + a1 + "\n" );
 
List l1 = new LinkedList();
l1.add( "Program" );
l1.add( "Creek" );
l1.add( "Java" );
l1.add( "Java" );
System.out.println( "LinkedList Elements" );
System.out.print( "\t" + l1 + "\n" );
 
Set s1 = new HashSet(); // 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 m1 = new HashMap(); // 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);

輸出:code

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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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