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<div align="center" class="title">JAVA程序員必讀：基礎篇（4）對象和簡單數據對象</div>
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<div align="center"><font color="#666666">編譯：ZSC/太平洋網絡學院</font></div>
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<div align="right" class="gray"><a href="mailto:tntst@pconline.com.cn">［責編:爆破手］</a></div>
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<p class="article"><b>對象和簡單數據對象</b></p>
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<p class="article"><b>（2）創建Strings 和StringBuffers</b></p>
<p class="article"> 字符串經常是由雙引號括起的一系列字符組成。比如，當有以下的字符串，JAVA平臺就創建一個String對象，它的數值為Goodluck。
</p>
<p class="article">"Goodluck"</p>
<p class="article">這個StringsDemo程序使用這個記述來創建字符串，它是由palindrome變量引用的：
</p>
<p class="article">String palindrome = "Dot saw I was Tod";</p>
<p class="article"> 同樣你可以利用其它方法來創建String對象：使用new關鍵字和構造函數。String類提供了幾個構造函數，它允許你提供字符串的初始值，它們是使用不同的資源的，比如字符的數組、字節的數組或者一個StringBuffer。</p>
<p class="article">char[] helloArray = { 'h', 'e', 'l', 'l', 'o' };</p>
<p class="article">helloString = new String(helloArray);</p>
<p class="article">System.out.println(helloString);</p>
<p class="article">上面的這段程序輸出為：hello。</p>
<p class="article"> 你必須使用new來創建一個StringBuffer。StringsDemo程序創建了SringBuffer，它是由dest引用的，這里使用了設置緩沖區容量的構造函數。
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<p class="article">String palindrome = "Dot saw I was Tod";</p>
<p class="article">int len = palindrome.length();</p>
<p class="article">StringBuffer dest = new StringBuffer(len);</p>
<p class="article"> 這個代碼創建了一個字符串的緩沖區，這個緩沖區的容量等于被palindrome引用的字符串的長度。這個確保了為dest只分配一個內存，因為它只有包含被復制的字符串那么大的空間。通過初始化字符串的緩沖區的容量，你最小化必須分配的內存空間。這就使得你的代碼更加有效，因為內存分配是相對高級的操作。</p>
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