📄 全面接触java集合框架 -.htm
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Collection</SPAN><SPAN
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</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">Object[]
toArray() </SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">：返回一个内含集合所有元素的</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">array</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">Object[]
toArray(Object[] a) </SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">：返回一个内含集合所有元素的</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">array</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">。运行期返回的</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">array</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">和参数</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">a</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">的型别相同，需要转换为正确型别。</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt"><BR><BR></SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt"> 此外，您还可以把集合转换成其它任何其它的对象数组。但是，您不能直接把集合转换成基本数据类型的数组，因为集合必须持有对象。</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt"><BR><BR></SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt"> </SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">“</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">斜体接口方法是可选的。因为一个接口实现必须实现所有接口方法，调用程序就需要一种途径来知道一个可选的方法是不是不受支持。如果调用一种可选方法时，一个</SPAN><SPAN
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UnsupportedOperationException </SPAN><SPAN
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RuntimeException </SPAN><SPAN
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try-catch </SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">”</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt"> </SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">Collection</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">get()</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">方法。如果要遍历</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">Collectin</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">Iterator</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt"> </SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">1.1.AbstractCollection
</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">AbstractCollection
</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">“</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">集合框架</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">”</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">类的基本功能。虽然您可以自行实现</SPAN><SPAN
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Collection </SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">接口的所有方法，但是，除了</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">iterator()</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">和</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">size()</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">方法在恰当的子类中实现以外，其它所有方法都由</SPAN><SPAN
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AbstractCollection </SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">类来提供实现。如果子类不覆盖某些方法，可选的如</SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">add()</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">之类的方法将抛出异常。</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt"><BR><BR></SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt"> </SPAN><SPAN
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style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">1.2.Iterator
</SPAN><SPAN
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lang=EN-US
style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt"><BR><BR></SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt"> </SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">Collection
</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">接口的</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">iterator()</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">方法返回一个</SPAN><SPAN
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Iterator</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">。</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">Iterator</SPAN><SPAN
style="FONT-SIZE: 9pt; FONT-FAMILY: 宋体; mso-font-kerning: 0pt; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-size: 12.0pt">接口方法能以迭代方式逐个访问集合中各个元素，并安全的从</SPAN><SPAN
lang=EN-US
style="FONT-SIZE: 9pt; FONT-FAMILY: Arial; mso-font-kerning: 0pt; mso-bidi-font-size: 12.0pt">Collection
</SPAN><SPAN
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