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<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;J<span style="background-color: rgb(255, 255, 255); color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size: 15px;">DK1.5引入了新的类型——枚举。在 Java 中它虽然算个“小”功能，却给我的开发带来了“大”方便。</span></p><p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"><strong style="border: 0px; margin: 0px; padding: 0px;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;用法一：常量</strong></p><p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;在JDK1.5 之前，我们定义常量都是： public static fianl…. 。现在好了，有了枚举，可以把相关的常量分组到一个枚举类型里，而且枚举提供了比常量更多的方法。</p><p style="text-align: center"><img src="/Public/forum/ueditor/image/20170630/1498786465388980.jpg" alt="1498786465388980.jpg"/></p><p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"><strong style="border: 0px; margin: 0px; padding: 0px;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;用法二：switch</strong></p><p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"><strong style="border: 0px; margin: 0px; padding: 0px;"></strong>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;JDK1.6之前的switch语句只支持int,char,enum类型，使用枚举，能让我们的代码可读性更强。</p><p style="text-align: center"><img src="/Public/forum/ueditor/image/20170630/1498786486920261.jpg" alt="1498786486920261.jpg"/></p><p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"><strong style="border: 0px; margin: 0px; padding: 0px;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;用法三：向枚举中添加新方法</strong></p><p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;如果打算自定义自己的方法，那么必须在enum实例序列的最后添加一个分号。而且 Java 要求必须先定义 enum实例。</p><p style="text-align: center"><img src="/Public/forum/ueditor/image/20170630/1498786506226840.jpg" alt="1498786506226840.jpg"/></p><p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"><strong style="border: 0px; margin: 0px; padding: 0px;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;用法四：覆盖枚举的方法</strong></p><p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"><strong style="border: 0px; margin: 0px; padding: 0px;"></strong>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;下面给出一个toString()方法覆盖的例子。</p><p style="text-align: center"><img src="/Public/forum/ueditor/image/20170630/1498786528627919.jpg" alt="1498786528627919.jpg"/></p><p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"><strong style="border: 0px; margin: 0px; padding: 0px;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;用法五：实现接口</strong></p><p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;所有的枚举都继承自java.lang.Enum类。由于Java 不支持多继承，所以枚举对象不能再继承其他类。</p><p style="text-align: center"><img src="/Public/forum/ueditor/image/20170630/1498786547488386.jpg" alt="1498786547488386.jpg"/></p><p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<strong style="border: 0px; margin: 0px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);">用法六：使用接口组织枚举</strong></p><p style="text-align: center"><img src="/Public/forum/ueditor/image/20170630/1498786779855679.jpg" alt="1498786779855679.jpg"/></p><p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"><strong style="border: 0px; margin: 0px; padding: 0px;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;用法七：关于枚举集合的使用</strong></p><p style="border: 0px; margin-top: 0px; margin-bottom: 20px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"><strong style="border: 0px; margin: 0px; padding: 0px;"></strong>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;java.util.EnumSet和java.util.EnumMap是两个枚举集合。EnumSet保证集合中的元素不重复；EnumMap中的key是enum类型，而value则可以是任意类型。关于这个两个集合的使用就不在这里赘述，可以参考JDK文档。</p><p><strong style="border: 0px; margin: 0px; padding: 0px; font-size: 15px; color: rgb(46, 46, 46); font-family: &quot;Microsoft YaHei&quot;, 宋体, &quot;Myriad Pro&quot;, Lato, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; white-space: normal; background-color: rgb(255, 255, 255);"></strong><br/></p>

论坛站务软件水平考试华为认证计算机等级PMP认证思科认证Photoshop3DMAX编程语言移动开发系统运维产品运营淘宝营销办公软件Ps修图云计算大数据摄影就业