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Commit a914c65

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owen1190
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‎contents/lookup-enum-by-string-value.md

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#通过String值查找enum中常量
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## 问题
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假设有一个枚举值
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public enum Blah
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{
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A,B,C,D
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}
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想通过一个String类型,找到所需要的枚举值。
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例如"A"->Blah.A
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是使用Enum.valueOf()方法吗?该如何使用
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## 回答
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Blah.valueOf("A")会得到Blah.A
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虽然api文档确实有静态方法valueOf()和values(),但是二者在编译期时才出现,而且在没出现在源程序中。
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例如可以采用Dialog.ModalityType显示了两种方法来处理这种情况。
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备注:Blah.valueOf("A")的方法是区分大小写,且不能含有空格。
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如果String值与enum中不相同的查找方法:
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public enum Blah
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{
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A("text1"),
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B("text2"),
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C("text3"),
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D("text4");
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private String text;
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Blah(String text)
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{
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this.text = text;
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}
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public String getText()
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{
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return this.text;
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}
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public static Blah fromString(String text)
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{
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if (text != null)
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{
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for (Blah b : Blah.values())
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{
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if (text.equalsIgnoreCase(b.text))
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{
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return b;
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}
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}
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}
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return null;
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}
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}
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备注:throw new IllegalArgumentException("No constant with text"+text+"found")会比直接抛出null更好
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原文链接:
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> http://stackoverflow.com/questions/604424/lookup-enum-by-string-value#

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