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<div align="center" class="title">JAVA程序员必读：基础篇（4）对象和简单数据对象</div>
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<div align="center"><font color="#666666">编译：ZSC/太平洋网络学院</font></div>
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<div align="right" class="gray"><a href="mailto:tntst@pconline.com.cn">［责编:爆破手］</a></div>
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<p class="article"><b>对象和简单数据对象</b></p>
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<p></p>
<p> <span class="article"><b>（4）修改StringBuffers</b> </span></p>
<p class="article"> reverseIt方法使用StringBuffer的append方法来增加一个字符到dest字符串末尾：
</p>
<p class="article">class ReverseString {</p>
<p class="article"> public static String reverseIt(String source)
{</p>
<p class="article"> int i, len = source.length();</p>
<p class="article"> StringBuffer dest = new StringBuffer(len);</p>
<p></p>
<p class="article"> for (i = (len - 1); i >= 0; i--) {</p>
<p class="article"> dest.append(source.charAt(i));</p>
<p class="article"> }</p>
<p class="article"> return dest.toString();</p>
<p class="article"> }</p>
<p class="article">}</p>
<p class="article"> 如果这个被增加的字符导致StringBuffer的大小超过当前的容量，这个StringBuffer就会为它分配更多的内存。因为内存分配示相对高级的操作，所以你可以同时初始化StringBuffer的容量为较合理的大小来使你的代码更有效率。比如reverseIt方法以初始的容量来构造StringBuffer等于源字符串的长度，以只为dest分配一次内存。</p>
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