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1 版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/qq_33451004/article/details/71247041 </div>
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5 <p>java中对bigdimical比较大小一般用的是bigdemical的compareTo方法；</p>
<pre class="prettyprint" name="code"><code class="hljs livecodeserver has-numbering">int <span class="hljs-operator">a</span> = bigdemical.compareTo(bigdemical2) <span class="hljs-operator">a</span> = -<span class="hljs-number">1</span>,表示bigdemical小于bigdemical2； <span class="hljs-operator">a</span> = <span class="hljs-number">0</span>,表示bigdemical等于bigdemical2； <span class="hljs-operator">a</span> = <span class="hljs-number">1</span>,表示bigdemical大于bigdemical2； </code><ul class="pre-numbering" style=""><li style="color: rgb(153, 153, 153);">1</li><li style="color: rgb(153, 153, 153);">2</li><li style="color: rgb(153, 153, 153);">3</li><li style="color: rgb(153, 153, 153);">4</li><li style="color: rgb(153, 153, 153);">5</li><li style="color: rgb(153, 153, 153);">6</li></ul></pre>
<p>2 bigdemical详解</p>
<pre class="prettyprint" name="code"><code class="hljs avrasm has-numbering"> BigDecimal bigDecimal = new BigDecimal(<span class="hljs-string">"4.44"</span>)<span class="hljs-comment">;</span> BigDecimal decimal = new BigDecimal(<span class="hljs-number">4.44</span>)<span class="hljs-comment">;</span> BigDecimal valueOf = BigDecimal<span class="hljs-preprocessor">.valueOf</span>(<span class="hljs-number">4.44</span>)<span class="hljs-comment">;</span> BigDecimal bigDecimal2 = new BigDecimal(<span class="hljs-number">999999999999</span>L)<span class="hljs-comment">;</span> BigDecimal valueOf2 = BigDecimal<span class="hljs-preprocessor">.valueOf</span>(<span class="hljs-number">999999999999</span>L)<span class="hljs-comment">;</span> System<span class="hljs-preprocessor">.err</span><span class="hljs-preprocessor">.println</span>(<span class="hljs-string">"bigDecimal="</span>+bigDecimal)<span class="hljs-comment">;</span> System<span class="hljs-preprocessor">.err</span><span class="hljs-preprocessor">.println</span>(<span class="hljs-string">"decimal="</span>+decimal)<span class="hljs-comment">;</span> System<span class="hljs-preprocessor">.err</span><span class="hljs-preprocessor">.println</span>(<span class="hljs-string">"valueOf="</span>+valueOf)<span class="hljs-comment">; </span> System<span class="hljs-preprocessor">.err</span><span class="hljs-preprocessor">.println</span>(<span class="hljs-string">"bigDecimal2="</span>+bigDecimal2)<span class="hljs-comment">;</span> System<span class="hljs-preprocessor">.err</span><span class="hljs-preprocessor">.println</span>(<span class="hljs-string">"valueOf2="</span>+valueOf2)<span class="hljs-comment">;</span> bigDecimal=<span class="hljs-number">4.44</span> decimal=<span class="hljs-number">4.44000000000000039079850466805510222911834716796875</span> valueOf=<span class="hljs-number">4.44</span> bigDecimal2=<span class="hljs-number">999999999999</span> valueOf2=<span class="hljs-number">999999999999</span> </code><ul class="pre-numbering" style=""><li style="color: rgb(153, 153, 153);">1</li><li style="color: rgb(153, 153, 153);">2</li><li style="color: rgb(153, 153, 153);">3</li><li style="color: rgb(153, 153, 153);">4</li><li style="color: rgb(153, 153, 153);">5</li><li style="color: rgb(153, 153, 153);">6</li><li style="color: rgb(153, 153, 153);">7</li><li style="color: rgb(153, 153, 153);">8</li><li style="color: rgb(153, 153, 153);">9</li><li style="color: rgb(153, 153, 153);">10</li><li style="color: rgb(153, 153, 153);">11</li><li style="color: rgb(153, 153, 153);">12</li><li style="color: rgb(153, 153, 153);">13</li><li style="color: rgb(153, 153, 153);">14</li><li style="color: rgb(153, 153, 153);">15</li><li style="color: rgb(153, 153, 153);">16</li><li style="color: rgb(153, 153, 153);">17</li><li style="color: rgb(153, 153, 153);">18</li><li style="color: rgb(153, 153, 153);">19</li><li style="color: rgb(153, 153, 153);">20</li></ul></pre>
<p>可以看出，double类型的数，在new bigdemical（）和Bigdemical.valueof()求出的结果是不一样的，因为new bigdemical（）内部是利用的double的构造方法，而这个构造方法jdk的描述是，其结果具有一定的不可预料性，很难对小数做出精确的描述；所以，在我们利用bigdemical的时候应尽量将参数变为字符串再进行计算；否则，针对double类型的小数就要用Bigdemical.valueOf(double d)了；</p>
<p>3 bigdemical的大于等于；</p>
<pre class="prettyprint" name="code"><code class="hljs livecodeserver has-numbering">其实很简单：<span class="hljs-built\_in">new</span> bigdemica(<span class="hljs-operator">a</span>).compareTo(<span class="hljs-built\_in">new</span> bigdemical(b)) >= <span class="hljs-number">0</span> 表示<span class="hljs-operator">a</span>大于等于b；小于等于同理；</code><ul class="pre-numbering" style=""><li style="color: rgb(153, 153, 153);">1</li></ul></pre> </div>
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