一、基本概念

MessageFormat用来格式化一个消息，通常是一个字符串。MessageFormat模式的主要部分：

FormatElement:

         { ArgumentIndex }

         { ArgumentIndex , FormatType }

         { ArgumentIndex , FormatType , FormatStyle }

 

FormatType: 

         number

         date

         time

         choice(需要使用ChoiceFormat)

 

FormatStyle:

         short

         medium

         long

         full

         integer

         currency

         percent

         SubformatPattern(子模式)

 

{0}、{1,number,short}、{2,number,#.#}属于FormatElement，0,1,2是ArgumentIndex

{1,number,short}里面的number属于FormatType，short则属于FormatStyle

{1,number,#.#}里面的#.#就属于子格式模式

 

 

二、例子

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    import java.text.MessageFormat;
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    String str = "{0}{1}{2}{3}{4}{5}{6}{7}{8}{9}{10}{11}{12}{13}{14}{15}{16}";
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    Object[] array = new Object[]{"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q"};
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    String value = MessageFormat.format(str, array);
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    System.out.println(value); // ABCDEFGHIJKLMNOPQ
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    String message = "oh, {0} is a person";
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    Object[] array = new Object[]{"ZhangSan"};
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    String value = MessageFormat.format(message, array);
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    System.out.println(value); // oh, ZhangSan is a person
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    String message = "oh, {0,number,#.#} is a number";
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    Object[] array = new Object[]{new Double(3.1415)};
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    String value = MessageFormat.format(message, array);
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    System.out.println(value); // oh, 3.1 is a number
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    // MessageFormat的format方法源码
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    public static String format(String pattern, Object ... arguments)
  24.  

    {
  25.  

    MessageFormat temp = new MessageFormat(pattern);
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    return temp.format(arguments);
  27.  

    }

对字符串的匹配比较智能

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    String str = "{0} | {1} | {0} | {1}";
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    Object[] array = new Object[] { "A", "B" };
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    String value = MessageFormat.format(str, array);
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    System.out.println(value); // A | B | A | B