Java中的MessageFormat类的用法

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

import java.text.MessageFormat;

String str = "{0}{1}{2}{3}{4}{5}{6}{7}{8}{9}{10}{11}{12}{13}{14}{15}{16}";
Object[] array = new Object[]{"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q"};
String value = MessageFormat.format(str, array);
System.out.println(value); // ABCDEFGHIJKLMNOPQ


String message = "oh, {0} is a person";
Object[] array = new Object[]{"ZhangSan"};
String value = MessageFormat.format(message, array);
System.out.println(value); // oh, ZhangSan is a person


String message = "oh, {0,number,#.#} is a number";
Object[] array = new Object[]{new Double(3.1415)};
String value = MessageFormat.format(message, array);
System.out.println(value); // oh, 3.1 is a number


// MessageFormat的format方法源码
public static String format(String pattern, Object ... arguments) 
{
    MessageFormat temp = new MessageFormat(pattern);
    return temp.format(arguments);
}

对字符串的匹配比较智能

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

原帖地址(节选):http://zqc-0101.iteye.com/blog/1140140