In the Java language, a text file with a .properties extension is used as a resource file. The content format of this type of file is similar to:

#Comment statement
some_key=some_value

form. Lines starting with # are used as comment lines and will be ignored when processed by the ResourceBundle class; the remaining lines can be described in the form of key name=value.

Java's ResourceBundle class can handle files in this form.

The use of the ResourceBundle class is also very simple. Let's use an example to illustrate.

We assume that we have the following 2 properties files:

TestProperties.properties???view?plainprint???#key=value?????userIdLabel=User?Id:??????userNameLabel=User?Name:?????#key=value?userIdLabel=User?Id:???userNameLabel=User?Name:???TestProperties_zh_CN.properties???view?plainprint???#key=value?????userIdLabel=用戶ID:??????userNameLabel=用戶名：?????#key=value?userIdLabel=用戶ID:???userNameLabel=用戶名：

You may notice that there is a _zh_CN name in the TestProperties_zh_CN.properties file name, which is actually used for localization of resource files. . What is localization? Let us briefly explain: When we develop the system, we often need to prepare different interfaces for users in different regions. For example, if a system is targeted at both English-speaking users and Chinese users, we must prepare 2 sets of interfaces for the system. The interface (including messages), one set is English interface and the other is Chinese interface. Of course, apart from the different interfaces, the system processes are exactly the same. Of course, it is impossible for us to develop two different systems for them respectively. What should we do? This requires localization of resources. In other words, different resource files are prepared according to the region or language of the user, so that different interfaces can be prepared for different users but the same set of system logic is used.

The two files above are two different sets of resources.

We use the ResourceBundle class to process the code of different resources:

TestProperties.java???view?plainprint???package?com.test.properties;??????????import?java.util.Enumeration;?????import?java.util.Locale;?????import?java.util.ResourceBundle;??????????public?class?TestProperties??{??????????????public?static?void?main(String?[]args)?{?????String?resourceFile?=?"com.test.properties.TestProperties";?????//創(chuàng)建一個默認的ResourceBundle對象?????//ResourceBundle會查找包com.test.properties下的TestProperties.properties的文件?????//com.test.properties是資源的包名，它跟普通java類的命名規(guī)則完全一樣：?????//-?區(qū)分大小寫?????//-?擴展名?.properties?省略。就像對于類可以省略掉?.class擴展名一樣?????//-?資源文件必須位于指定包的路徑之下（位于所指定的classpath中）?????//另外，對于非西歐字符（比如中日韓文等），需要使用native2ascii命令或類似工具將其轉換成ascii碼文件格式，否則會顯示亂碼。?????System.out.println("---Default?Locale---");?????ResourceBundle?resource?=?ResourceBundle.getBundle(resourceFile);??????????testResourceBundle(resource);??????????System.out.println("---Locale.SIMPLIFIED_CHINESE---");??????????//創(chuàng)建一個指定Locale（本地化）的ResourceBundle對象，這里指定為Locale.SIMPLIFIED_CHINESE?????//所以ResourceBundle會查找com.test.properties.TestProperties_zh_CN.properties的文件?????//?????//中文相關的Locale有：?????//Locale.SIMPLIFIED_CHINESE?:?zh_CN?????resource?=?ResourceBundle.getBundle(resourceFile,?Locale.SIMPLIFIED_CHINESE);?????//Locale.CHINA??:?zh_CN?????//Locale.CHINESE:?zh?????testResourceBundle(resource);??????????//顯示?????//?????????}??????????????????private?static?void?testResourceBundle(ResourceBundle?resource)?{?????//取得指定關鍵字的value值?????String?userIdLabel?=?resource.getString("userIdLabel");?????System.out.println(userIdLabel);??????????//取得所有key值?????Enumeration?enu?=?resource.getKeys();??????????System.out.println("keys:");?????while(enu.hasMoreElements())?{?????????System.out.println(enu.nextElement());?????}?????????}?????}?????package?com.test.properties;???import?java.util.Enumeration;??import?java.util.Locale;??import?java.util.ResourceBundle;???public?class?TestProperties??{???????public?static?void?main(String?[]args)?{??String?resourceFile?=?"com.test.properties.TestProperties";??//創(chuàng)建一個默認的ResourceBundle對象??//ResourceBundle會查找包com.test.properties下的TestProperties.properties的文件??//com.test.properties是資源的包名，它跟普通java類的命名規(guī)則完全一樣：??//-?區(qū)分大小寫??//-?擴展名?.properties?省略。就像對于類可以省略掉?.class擴展名一樣??//-?資源文件必須位于指定包的路徑之下（位于所指定的classpath中）??//另外，對于非西歐字符（比如中日韓文等），需要使用native2ascii命令或類似工具將其轉換成ascii碼文件格式，否則會顯示亂碼。??System.out.println("---Default?Locale---");??ResourceBundle?resource?=?ResourceBundle.getBundle(resourceFile);???testResourceBundle(resource);???System.out.println("---Locale.SIMPLIFIED_CHINESE---");???//創(chuàng)建一個指定Locale（本地化）的ResourceBundle對象，這里指定為Locale.SIMPLIFIED_CHINESE??//所以ResourceBundle會查找com.test.properties.TestProperties_zh_CN.properties的文件??//??//中文相關的Locale有：??//Locale.SIMPLIFIED_CHINESE?:?zh_CN??resource?=?ResourceBundle.getBundle(resourceFile,?Locale.SIMPLIFIED_CHINESE);??//Locale.CHINA??:?zh_CN??//Locale.CHINESE:?zh??testResourceBundle(resource);???//顯示??//??????}????????????private?static?void?testResourceBundle(ResourceBundle?resource)?{??//取得指定關鍵字的value值??String?userIdLabel?=?resource.getString("userIdLabel");??System.out.println(userIdLabel);???//取得所有key值??Enumeration?enu?=?resource.getKeys();???System.out.println("keys:");??while(enu.hasMoreElements())?{??????System.out.println(enu.nextElement());??}??????}??}

Explanation:

1, for ease of understanding, we put the explanation in the Java source code, here No more details.

2. For the Chinese resource file TestProperties_zh_CN.properties, you need to use the native2ascii command to convert it to ascii code. For example:

native2ascii -encoding UTF-8 c:\TestProperties_zh_CN.properties c:\java\com\test\properties\TestProperties_zh_CN.properties

As for the detailed usage of native2ascii, I will not go into details here. .

3. Save the above three files in the c:\java\com\test\properties\ directory. Among them, TestProperties_zh_CN.properties is a file converted by native2ascii.

4, compile and execute, it will be displayed on the screen:

c:\java\javac com.test.properties.TestProperties.java

c:\java\ java com.test.properties.TestProperties
---Default Locale---
User Id:
keys:
userNameLabel
userIdLabel
---Locale.SIMPLIFIED_CHINESE---
User ID:
keys:
userNameLabel
userIdLabel

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