文件大小单位转换代码,Java代码库,德仔网

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【Java】文件大小单位转换
作者: / 发布于2011/1/14/ 544
<div><span style="color: #0000ff">import</span><span style="color: #000000"> java.text.DecimalFormat;
</span><span style="color: #0000ff">import</span><span style="color: #000000"> java.util.Hashtable;

</span><span style="color: #008000">/**</span><span style="color: #008000">
* 文件大小单位转换
* </span><span style="color: #808080">@author</span><span style="color: #008000"> Administrator
* 
</span><span style="color: #008000">*/</span><span style="color: #000000">
</span><span style="color: #0000ff">public</span><span style="color: #000000"> </span><span style="color: #0000ff">class</span><span style="color: #000000"> UnitsConversion </span><span style="color: #0000ff">extends</span><span style="color: #000000"> DecimalFormat {

 </span><span style="color: #0000ff">private</span><span style="color: #000000"> </span><span style="color: #0000ff">static</span><span style="color: #000000"> </span><span style="color: #0000ff">final</span><span style="color: #000000"> </span><span style="color: #0000ff">long</span><span style="color: #000000"> serialVersionUID </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #000000">3168068393840262910L</span><span style="color: #000000">;
 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 存放有效单位的数组
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">private</span><span style="color: #000000"> </span><span style="color: #0000ff">static</span><span style="color: #000000"> Hashtable</span><span style="color: #000000"><</span><span style="color: #000000">String, String</span><span style="color: #000000">></span><span style="color: #000000"> validUnits </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #0000ff">new</span><span style="color: #000000"> Hashtable</span><span style="color: #000000"><</span><span style="color: #000000">String, String</span><span style="color: #000000">></span><span style="color: #000000">();
 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 限制文件大小上限为1G
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">private</span><span style="color: #000000"> </span><span style="color: #0000ff">static</span><span style="color: #000000"> </span><span style="color: #0000ff">int</span><span style="color: #000000"> GB_MAX_SIZE </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #000000">1</span><span style="color: #000000">;
 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 最大的MB值
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">private</span><span style="color: #000000"> </span><span style="color: #0000ff">static</span><span style="color: #000000"> </span><span style="color: #0000ff">int</span><span style="color: #000000"> MB_MAX_SIZE </span><span style="color: #000000">=</span><span style="color: #000000"> GB_MAX_SIZE </span><span style="color: #000000">*</span><span style="color: #000000"> </span><span style="color: #000000">1024</span><span style="color: #000000">;
 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 最大的KB值
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">private</span><span style="color: #000000"> </span><span style="color: #0000ff">static</span><span style="color: #000000"> </span><span style="color: #0000ff">int</span><span style="color: #000000"> KB_MAX_SIZE </span><span style="color: #000000">=</span><span style="color: #000000"> MB_MAX_SIZE </span><span style="color: #000000">*</span><span style="color: #000000"> </span><span style="color: #000000">1024</span><span style="color: #000000">;
 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 最大的Bytes值
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">private</span><span style="color: #000000"> </span><span style="color: #0000ff">static</span><span style="color: #000000"> </span><span style="color: #0000ff">int</span><span style="color: #000000"> BYTES_MAX_SIZE </span><span style="color: #000000">=</span><span style="color: #000000"> KB_MAX_SIZE </span><span style="color: #000000">*</span><span style="color: #000000"> </span><span style="color: #000000">1024</span><span style="color: #000000">;
 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 数字部分的值
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">private</span><span style="color: #000000"> Double numPart;
 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 原始的单位字符串
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">private</span><span style="color: #000000"> String originalUnit;
 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 标准的单位字符串
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">private</span><span style="color: #000000"> String unit;
 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 转换后的结果
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">private</span><span style="color: #000000"> String result;

 </span><span style="color: #008000">//</span><span style="color: #008000"> 添加所有有效单位</span><span style="color: #008000">
</span><span style="color: #000000"> </span><span style="color: #0000ff">static</span><span style="color: #000000"> {
 validUnits.put(</span><span style="color: #000000">"</span><span style="color: #000000">字节</span><span style="color: #000000">"</span><span style="color: #000000">, </span><span style="color: #000000">"</span><span style="color: #000000">Bytes</span><span style="color: #000000">"</span><span style="color: #000000">);
 validUnits.put(</span><span style="color: #000000">"</span><span style="color: #000000">bytes</span><span style="color: #000000">"</span><span style="color: #000000">, </span><span style="color: #000000">"</span><span style="color: #000000">Bytes</span><span style="color: #000000">"</span><span style="color: #000000">);
 validUnits.put(</span><span style="color: #000000">"</span><span style="color: #000000">byte</span><span style="color: #000000">"</span><span style="color: #000000">, </span><span style="color: #000000">"</span><span style="color: #000000">Bytes</span><span style="color: #000000">"</span><span style="color: #000000">);
 validUnits.put(</span><span style="color: #000000">"</span><span style="color: #000000">kb</span><span style="color: #000000">"</span><span style="color: #000000">, </span><span style="color: #000000">"</span><span style="color: #000000">KB</span><span style="color: #000000">"</span><span style="color: #000000">);
 validUnits.put(</span><span style="color: #000000">"</span><span style="color: #000000">k</span><span style="color: #000000">"</span><span style="color: #000000">, </span><span style="color: #000000">"</span><span style="color: #000000">KB</span><span style="color: #000000">"</span><span style="color: #000000">);
 validUnits.put(</span><span style="color: #000000">"</span><span style="color: #000000">兆</span><span style="color: #000000">"</span><span style="color: #000000">, </span><span style="color: #000000">"</span><span style="color: #000000">MB</span><span style="color: #000000">"</span><span style="color: #000000">);
 validUnits.put(</span><span style="color: #000000">"</span><span style="color: #000000">mb</span><span style="color: #000000">"</span><span style="color: #000000">, </span><span style="color: #000000">"</span><span style="color: #000000">MB</span><span style="color: #000000">"</span><span style="color: #000000">);
 validUnits.put(</span><span style="color: #000000">"</span><span style="color: #000000">m</span><span style="color: #000000">"</span><span style="color: #000000">, </span><span style="color: #000000">"</span><span style="color: #000000">MB</span><span style="color: #000000">"</span><span style="color: #000000">);
 validUnits.put(</span><span style="color: #000000">"</span><span style="color: #000000">gb</span><span style="color: #000000">"</span><span style="color: #000000">, </span><span style="color: #000000">"</span><span style="color: #000000">GB</span><span style="color: #000000">"</span><span style="color: #000000">);
 validUnits.put(</span><span style="color: #000000">"</span><span style="color: #000000">g</span><span style="color: #000000">"</span><span style="color: #000000">, </span><span style="color: #000000">"</span><span style="color: #000000">GB</span><span style="color: #000000">"</span><span style="color: #000000">);
 }

 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 构造方法：指定了数字格式，初始所有属性为NULL
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">public</span><span style="color: #000000"> UnitsConversion() {
 </span><span style="color: #0000ff">super</span><span style="color: #000000">(</span><span style="color: #000000">"</span><span style="color: #000000">########.##</span><span style="color: #000000">"</span><span style="color: #000000">);
 numPart </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #0000ff">null</span><span style="color: #000000">;
 result </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #0000ff">null</span><span style="color: #000000">;
 unit </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #0000ff">null</span><span style="color: #000000">;
 originalUnit </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #0000ff">null</span><span style="color: #000000">;
 }

 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 根据单位、数字大小按照常用的转换原则进行转换
 * 
 * </span><span style="color: #808080">@param</span><span style="color: #008000"> input
 * </span><span style="color: #808080">@return</span><span style="color: #008000"> 成功转换后的结果是非空字符串；若失败了，结果为空字符串
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">public</span><span style="color: #000000"> String defaultConversion(String input) {
 analyzeString(input);
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (result </span><span style="color: #000000">!=</span><span style="color: #000000"> </span><span style="color: #0000ff">null</span><span style="color: #000000">) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> result;
 }
 </span><span style="color: #008000">//</span><span style="color: #008000"> 单位 Bytes</span><span style="color: #008000">
</span><span style="color: #000000"> </span><span style="color: #0000ff">if</span><span style="color: #000000"> (unit.equals(</span><span style="color: #000000">"</span><span style="color: #000000">Bytes</span><span style="color: #000000">"</span><span style="color: #000000">)) {
 </span><span style="color: #0000ff">int</span><span style="color: #000000"> numPart2Int </span><span style="color: #000000">=</span><span style="color: #000000"> numPart.intValue();
 </span><span style="color: #008000">//</span><span style="color: #008000"> 输入大小与1G相差0.5M之内，返回1GB</span><span style="color: #008000">
</span><span style="color: #000000"> </span><span style="color: #0000ff">if</span><span style="color: #000000"> ((BYTES_MAX_SIZE </span><span style="color: #000000">-</span><span style="color: #000000"> numPart2Int) </span><span style="color: #000000"><</span><span style="color: #000000"> (</span><span style="color: #000000">1024</span><span style="color: #000000"> </span><span style="color: #000000">*</span><span style="color: #000000"> </span><span style="color: #000000">1024</span><span style="color: #000000">) </span><span style="color: #000000">/</span><span style="color: #000000"> </span><span style="color: #000000">2</span><span style="color: #000000">) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #000000">"</span><span style="color: #000000">1 GB</span><span style="color: #000000">"</span><span style="color: #000000">;
 }
 </span><span style="color: #008000">//</span><span style="color: #008000"> (0,1KB)</span><span style="color: #008000">
</span><span style="color: #000000"> </span><span style="color: #0000ff">if</span><span style="color: #000000"> (numPart2Int </span><span style="color: #000000"><</span><span style="color: #000000"> </span><span style="color: #000000">1024</span><span style="color: #000000">) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> numPart2Int </span><span style="color: #000000">+</span><span style="color: #000000"> </span><span style="color: #000000">"</span><span style="color: #000000"> Bytes</span><span style="color: #000000">"</span><span style="color: #000000">;
 }
 </span><span style="color: #008000">//</span><span style="color: #008000"> [1KB,1023KB]</span><span style="color: #008000">
</span><span style="color: #000000"> </span><span style="color: #0000ff">if</span><span style="color: #000000"> (numPart2Int </span><span style="color: #000000">>=</span><span style="color: #000000"> </span><span style="color: #000000">1024</span><span style="color: #000000"> </span><span style="color: #000000">&&</span><span style="color: #000000"> numPart2Int </span><span style="color: #000000"><=</span><span style="color: #000000"> (</span><span style="color: #000000">1024</span><span style="color: #000000"> </span><span style="color: #000000">-</span><span style="color: #000000"> </span><span style="color: #000000">1</span><span style="color: #000000">) </span><span style="color: #000000">*</span><span style="color: #000000"> </span><span style="color: #000000">1024</span><span style="color: #000000">) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> format(numPart </span><span style="color: #000000">/</span><span style="color: #000000"> </span><span style="color: #000000">1024</span><span style="color: #000000">) </span><span style="color: #000000">+</span><span style="color: #000000"> </span><span style="color: #000000">"</span><span style="color: #000000"> KB</span><span style="color: #000000">"</span><span style="color: #000000">;
 }
 </span><span style="color: #008000">//</span><span style="color: #008000"> (1023KB,1GB)</span><span style="color: #008000">
</span><span style="color: #000000"> </span><span style="color: #0000ff">if</span><span style="color: #000000"> (numPart2Int </span><span style="color: #000000">></span><span style="color: #000000"> (</span><span style="color: #000000">1024</span><span style="color: #000000"> </span><span style="color: #000000">-</span><span style="color: #000000"> </span><span style="color: #000000">1</span><span style="color: #000000">) </span><span style="color: #000000">*</span><span style="color: #000000"> </span><span style="color: #000000">1024</span><span style="color: #000000"> </span><span style="color: #000000">&&</span><span style="color: #000000"> numPart2Int </span><span style="color: #000000"><</span><span style="color: #000000"> BYTES_MAX_SIZE) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> format(numPart </span><span style="color: #000000">/</span><span style="color: #000000"> (</span><span style="color: #000000">1024</span><span style="color: #000000"> </span><span style="color: #000000">*</span><span style="color: #000000"> </span><span style="color: #000000">1024</span><span style="color: #000000">)) </span><span style="color: #000000">+</span><span style="color: #000000"> </span><span style="color: #000000">"</span><span style="color: #000000"> MB</span><span style="color: #000000">"</span><span style="color: #000000">;
 } </span><span style="color: #0000ff">else</span><span style="color: #000000">
 result </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #000000">""</span><span style="color: #000000">;
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> result;
 }

 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (unit.equals(</span><span style="color: #000000">"</span><span style="color: #000000">KB</span><span style="color: #000000">"</span><span style="color: #000000">)) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #000000">"</span><span style="color: #000000">还没实现....</span><span style="color: #000000">"</span><span style="color: #000000">;
 }

 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (unit.equals(</span><span style="color: #000000">"</span><span style="color: #000000">MB</span><span style="color: #000000">"</span><span style="color: #000000">)) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #000000">"</span><span style="color: #000000">还没实现....</span><span style="color: #000000">"</span><span style="color: #000000">;
 }

 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (unit.equals(</span><span style="color: #000000">"</span><span style="color: #000000">GB</span><span style="color: #000000">"</span><span style="color: #000000">)) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #000000">"</span><span style="color: #000000">还没实现....</span><span style="color: #000000">"</span><span style="color: #000000">;
 }
 result </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #000000">""</span><span style="color: #000000">;
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> result;
 }

 </span><span style="color: #008000">/**</span><span style="color: #008000">
* 把字符串的数字部分与单位分离，并对数字、单位的有效性进行检验， 若有非法状况，把结果赋值为 "" ，将其返回给用户
*
* </span><span style="color: #808080">@param</span><span style="color: #008000"> input
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">public</span><span style="color: #000000"> </span><span style="color: #0000ff">void</span><span style="color: #000000"> analyzeString(String input) {
 </span><span style="color: #008000">//</span><span style="color: #008000"> 初步检验输入的字符串</span><span style="color: #008000">
</span><span style="color: #000000"> </span><span style="color: #0000ff">if</span><span style="color: #000000"> (input </span><span style="color: #000000">==</span><span style="color: #000000"> </span><span style="color: #0000ff">null</span><span style="color: #000000"> </span><span style="color: #000000">||</span><span style="color: #000000"> input.trim().length() </span><span style="color: #000000"><</span><span style="color: #000000"> </span><span style="color: #000000">2</span><span style="color: #000000">) {
 System.out.println(</span><span style="color: #000000">"</span><span style="color: #000000">输入的字符串有误</span><span style="color: #000000">"</span><span style="color: #000000">);
 result </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #000000">""</span><span style="color: #000000">;
 </span><span style="color: #0000ff">return</span><span style="color: #000000">;
 }
 input </span><span style="color: #000000">=</span><span style="color: #000000"> input.replaceAll(</span><span style="color: #000000">"</span><span style="color: #000000"> </span><span style="color: #000000">"</span><span style="color: #000000">, </span><span style="color: #000000">""</span><span style="color: #000000">);
 </span><span style="color: #0000ff">int</span><span style="color: #000000"> firstIndexOfUnit;</span><span style="color: #008000">//</span><span style="color: #008000"> 单位的起始位置</span><span style="color: #008000">
</span><span style="color: #000000"> String strOfNum;</span><span style="color: #008000">//</span><span style="color: #008000"> 数字部分的字符串
 </span><span style="color: #008000">//</span><span style="color: #008000"> 从尾部开始遍历字符串</span><span style="color: #008000">
</span><span style="color: #000000"> </span><span style="color: #0000ff">for</span><span style="color: #000000"> (</span><span style="color: #0000ff">int</span><span style="color: #000000"> i </span><span style="color: #000000">=</span><span style="color: #000000"> input.length() </span><span style="color: #000000">-</span><span style="color: #000000"> </span><span style="color: #000000">1</span><span style="color: #000000">; i </span><span style="color: #000000">>=</span><span style="color: #000000"> </span><span style="color: #000000">0</span><span style="color: #000000">; i</span><span style="color: #000000">--</span><span style="color: #000000">) {
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (Character.isDigit(input.charAt(i))) {
 firstIndexOfUnit </span><span style="color: #000000">=</span><span style="color: #000000"> i </span><span style="color: #000000">+</span><span style="color: #000000"> </span><span style="color: #000000">1</span><span style="color: #000000">;
 originalUnit </span><span style="color: #000000">=</span><span style="color: #000000"> input.substring(firstIndexOfUnit,
 input.length()).toLowerCase();
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (</span><span style="color: #000000">!</span><span style="color: #000000">isValidUnit(originalUnit)) {
 System.out.println(</span><span style="color: #000000">"</span><span style="color: #000000">无效单位。</span><span style="color: #000000">"</span><span style="color: #000000">);
 result </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #000000">""</span><span style="color: #000000">;
 </span><span style="color: #0000ff">return</span><span style="color: #000000">;
 }
 unit </span><span style="color: #000000">=</span><span style="color: #000000"> validUnits.get(originalUnit);
 strOfNum </span><span style="color: #000000">=</span><span style="color: #000000"> input.substring(</span><span style="color: #000000">0</span><span style="color: #000000">, firstIndexOfUnit);
 numPart </span><span style="color: #000000">=</span><span style="color: #000000"> Double.parseDouble(strOfNum);
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (</span><span style="color: #000000">!</span><span style="color: #000000">isValidNum(numPart, unit)) {
 System.out.println(</span><span style="color: #000000">"</span><span style="color: #000000">文件大小非法</span><span style="color: #000000">"</span><span style="color: #000000">);
 result </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #000000">""</span><span style="color: #000000">;
 </span><span style="color: #0000ff">return</span><span style="color: #000000">;
 }
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (numPart </span><span style="color: #000000">==</span><span style="color: #000000"> </span><span style="color: #000000">0</span><span style="color: #000000">) {
 result </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #000000">"</span><span style="color: #000000">0 Bytes</span><span style="color: #000000">"</span><span style="color: #000000">;
 </span><span style="color: #0000ff">return</span><span style="color: #000000">;
 }
 </span><span style="color: #0000ff">break</span><span style="color: #000000">;
 }
 }
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (unit </span><span style="color: #000000">==</span><span style="color: #000000"> </span><span style="color: #0000ff">null</span><span style="color: #000000"> </span><span style="color: #000000">||</span><span style="color: #000000"> numPart </span><span style="color: #000000">==</span><span style="color: #000000"> </span><span style="color: #0000ff">null</span><span style="color: #000000">) {
 System.out.println(</span><span style="color: #000000">"</span><span style="color: #000000">输入的字符串有误</span><span style="color: #000000">"</span><span style="color: #000000">);
 result </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #000000">""</span><span style="color: #000000">;
 </span><span style="color: #0000ff">return</span><span style="color: #000000">;
 }

 }

 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 文件大小越界检查
 * 
 * </span><span style="color: #808080">@param</span><span style="color: #008000"> num
 * </span><span style="color: #808080">@param</span><span style="color: #008000"> unit
 * </span><span style="color: #808080">@return</span><span style="color: #008000"> 在1G范围内（包括1G），返回true；否则返回false
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">public</span><span style="color: #000000"> </span><span style="color: #0000ff">boolean</span><span style="color: #000000"> isValidNum(Double num, String unit) {
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (num </span><span style="color: #000000">==</span><span style="color: #000000"> </span><span style="color: #0000ff">null</span><span style="color: #000000"> </span><span style="color: #000000">||</span><span style="color: #000000"> num </span><span style="color: #000000"><</span><span style="color: #000000"> </span><span style="color: #000000">0</span><span style="color: #000000"> </span><span style="color: #000000">||</span><span style="color: #000000"> num </span><span style="color: #000000">></span><span style="color: #000000"> BYTES_MAX_SIZE) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #0000ff">false</span><span style="color: #000000">;
 }
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (unit.equals(</span><span style="color: #000000">"</span><span style="color: #000000">KB</span><span style="color: #000000">"</span><span style="color: #000000">) </span><span style="color: #000000">&&</span><span style="color: #000000"> num </span><span style="color: #000000">></span><span style="color: #000000"> KB_MAX_SIZE) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #0000ff">false</span><span style="color: #000000">;
 }
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (unit.equals(</span><span style="color: #000000">"</span><span style="color: #000000">MB</span><span style="color: #000000">"</span><span style="color: #000000">) </span><span style="color: #000000">&&</span><span style="color: #000000"> num </span><span style="color: #000000">></span><span style="color: #000000"> MB_MAX_SIZE) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #0000ff">false</span><span style="color: #000000">;
 }
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (unit.equals(</span><span style="color: #000000">"</span><span style="color: #000000">GB</span><span style="color: #000000">"</span><span style="color: #000000">) </span><span style="color: #000000">&&</span><span style="color: #000000"> num </span><span style="color: #000000">></span><span style="color: #000000"> GB_MAX_SIZE) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #0000ff">false</span><span style="color: #000000">;
 }
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #0000ff">true</span><span style="color: #000000">;
 }

 </span><span style="color: #008000">/**</span><span style="color: #008000">
 * 检查原始单位originalUnit是否有效
 * 
 * </span><span style="color: #808080">@param</span><span style="color: #008000"> originalUnit
 * </span><span style="color: #808080">@return</span><span style="color: #008000"> 若originalUnit为空，那么会给他赋默认值 bytes ，并返回true；
 * 若originalUnit是有效单位集合中之一，返回true。
 </span><span style="color: #008000">*/</span><span style="color: #000000">
 </span><span style="color: #0000ff">public</span><span style="color: #000000"> </span><span style="color: #0000ff">boolean</span><span style="color: #000000"> isValidUnit(String originalUnit) {
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (originalUnit </span><span style="color: #000000">==</span><span style="color: #000000"> </span><span style="color: #0000ff">null</span><span style="color: #000000"> </span><span style="color: #000000">||</span><span style="color: #000000"> originalUnit.trim().length() </span><span style="color: #000000"><</span><span style="color: #000000"> </span><span style="color: #000000">1</span><span style="color: #000000">) {
 originalUnit </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #000000">"</span><span style="color: #000000">bytes</span><span style="color: #000000">"</span><span style="color: #000000">;
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #0000ff">true</span><span style="color: #000000">;
 }
 </span><span style="color: #0000ff">for</span><span style="color: #000000"> (String validUnit : validUnits.keySet()) {
 </span><span style="color: #0000ff">if</span><span style="color: #000000"> (validUnit.equalsIgnoreCase(originalUnit)) {
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #0000ff">true</span><span style="color: #000000">;
 }
 }
 </span><span style="color: #0000ff">return</span><span style="color: #000000"> </span><span style="color: #0000ff">false</span><span style="color: #000000">;
 }
 </span><span style="color: #008000">//</span><span style="color: #008000">测试</span><span style="color: #008000">
</span><span style="color: #000000"> </span><span style="color: #0000ff">public</span><span style="color: #000000"> </span><span style="color: #0000ff">static</span><span style="color: #000000"> </span><span style="color: #0000ff">void</span><span style="color: #000000"> main(String[] args) {
 System.out.println(</span><span style="color: #000000">"</span><span style="color: #000000">-------------</span><span style="color: #000000">"</span><span style="color: #000000">);
 </span><span style="color: #0000ff">for</span><span style="color: #000000"> (</span><span style="color: #0000ff">int</span><span style="color: #000000"> i </span><span style="color: #000000">=</span><span style="color: #000000"> </span><span style="color: #000000">1020</span><span style="color: #000000"> </span><span style="color: #000000">*</span><span style="color: #000000"> </span><span style="color: #000000">1024</span><span style="color: #000000">; i </span><span style="color: #000000"><=</span><span style="color: #000000"> </span><span style="color: #000000">1024</span><span style="color: #000000"> </span><span style="color: #000000">*</span><span style="color: #000000"> </span><span style="color: #000000">1111</span><span style="color: #000000">; i </span><span style="color: #000000">+=</span><span style="color: #000000"> </span><span style="color: #000000">9</span><span style="color: #000000">) {
 String input </span><span style="color: #000000">=</span><span style="color: #000000"> i </span><span style="color: #000000">+</span><span style="color: #000000"> </span><span style="color: #000000">"</span><span style="color: #000000"> </span><span style="color: #000000">"</span><span style="color: #000000">;
 System.out.println(input </span><span style="color: #000000">+</span><span style="color: #000000"> </span><span style="color: #000000">"</span><span style="color: #000000"> ---> </span><span style="color: #000000">"</span><span style="color: #000000">
 </span><span style="color: #000000">+</span><span style="color: #000000"> </span><span style="color: #0000ff">new</span><span style="color: #000000"> UnitsConversion().defaultConversion(input));
 }
 }

}

</span></div>
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