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java核心类学习之Collection基础类

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作者 正文
   发表时间:2011-10-31  

         Collection 集合类,基础
1. 所有的集合操作都实现了Collection这个基类接口
2. 继承了Collection的接口有:List,Set 这2个接口
3. 实现了Collection的类有:AbstractCollection这个抽象类
4. Collection接口定义的方法解析如下:
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Priority="69" SemiHidden="false" UnhideWhenUsed="false" Name="Medium Grid 3 Accent 5"/> <w:LsdException Locked="false" Priority="70" SemiHidden="false" UnhideWhenUsed="false" Name="Dark List Accent 5"/> <w:LsdException Locked="false" Priority="71" SemiHidden="false" UnhideWhenUsed="false" Name="Colorful Shading Accent 5"/> <w:LsdException Locked="false" Priority="72" SemiHidden="false" UnhideWhenUsed="false" Name="Colorful List Accent 5"/> <w:LsdException Locked="false" Priority="73" SemiHidden="false" UnhideWhenUsed="false" Name="Colorful Grid Accent 5"/> <w:LsdException Locked="false" Priority="60" SemiHidden="false" UnhideWhenUsed="false" Name="Light Shading Accent 6"/> <w:LsdException Locked="false" Priority="61" SemiHidden="false" UnhideWhenUsed="false" Name="Light List Accent 6"/> <w:LsdException Locked="false" Priority="62" SemiHidden="false" UnhideWhenUsed="false" Name="Light Grid Accent 6"/> <w:LsdException Locked="false" Priority="63" SemiHidden="false" UnhideWhenUsed="false" Name="Medium Shading 1 Accent 6"/> <w:LsdException Locked="false" Priority="64" SemiHidden="false" UnhideWhenUsed="false" Name="Medium Shading 2 Accent 6"/> <w:LsdException Locked="false" Priority="65" SemiHidden="false" UnhideWhenUsed="false" Name="Medium List 1 Accent 6"/> <w:LsdException Locked="false" Priority="66" SemiHidden="false" UnhideWhenUsed="false" Name="Medium List 2 Accent 6"/> <w:LsdException Locked="false" Priority="67" SemiHidden="false" UnhideWhenUsed="false" Name="Medium Grid 1 Accent 6"/> <w:LsdException Locked="false" Priority="68" SemiHidden="false" UnhideWhenUsed="false" Name="Medium Grid 2 Accent 6"/> <w:LsdException Locked="false" Priority="69" SemiHidden="false" UnhideWhenUsed="false" Name="Medium Grid 3 Accent 6"/> <w:LsdException Locked="false" Priority="70" SemiHidden="false" UnhideWhenUsed="false" Name="Dark List Accent 6"/> <w:LsdException Locked="false" Priority="71" SemiHidden="false" UnhideWhenUsed="false" Name="Colorful Shading Accent 6"/> 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Name="TOC Heading"/> </w:LatentStyles> </xml><![endif]--><!-- [if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:普通表格; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.5pt; mso-bidi-font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-font-kerning:1.0pt;} </style> <![endif]-->

Method…..
  1.int Size();

   返回此集合中的所有元素数量 , 返回值 int,

  2.boolean isEmpty();

   返回此集合中不包含的元素 , 返回值 boolean

  3.boolean contains(Object o);

   判断此集合中是否有某个对象,返回值 boolean

  4.Iterator<E> iterator();

   返回此集合的泛型迭代器 ( 可以是任意类型的 ), 返回值 Iterator<E>

  5.Object[] toArray();

   将集合转换为数组,如果该集合被迭代过,那么转换的数组与迭代后的保持一致的顺序。

  6.<T> T[] to Array(T[] a);

   将集合转换为数组,返回类型为泛型

  7.boolean add(E e);

   添加集合元素对象, E 对象为 Collection<E> 指定的泛型对象,返回是否添加成功 ,Boolean

  8.boolean remove(Object o);

   删除集合元素对象,返回是否删除成功 boolean

  9.boolean containsAll(Collection<?> c)

   判断此集合中的 u 所有元素是否存在于参数 C 集合中,返回值 boolean

  10.boolean addAll(Collection<? Extends E> c);

   把参数集合 C 的所有元素一次性 添加到此集合中,返回值 boolean

  11.boolean removeAll(Collection<?> c);

   删除此集合中存在于参数 C 集合中的所有元素,返回值 boolean

  12.boolean retainAll(Collection<?> c);

   保留此集合中与集合参数 C 中相同的所有元素,与 removeAll 相反返回值 boolean,

  13.void clear();

清空集合所有元素对象 .

  14.boolean equals(Object o);

比较此集合对象与集合参数 o 对象是否相等,返回值 boolean

  15int hashCode();

    返回此集合的哈希代码值 , 返回值 int.

 

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