Java 相当于 app.config？
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Java equivalent to app.config?
提问by Omar Kooheji
Is there a Java equivalent to .NET's App.Config?
是否有相当于 .NET 的 App.Config 的 Java？
If not is there a standard way to keep you application settings, so that they can be changed after an app has been distributed?
如果没有，是否有一种标准方法可以保留您的应用程序设置，以便在分发应用程序后可以更改它们？
采纳答案by Powerlord
For WebApps, web.xml can be used to store application settings.
对于 WebApps，web.xml 可用于存储应用程序设置。
Other than that, you can use the Propertiesclass to read and write properties files.
除此之外，您可以使用Properties类来读取和写入属性文件。
You may also want to look at the Preferencesclass, which is used to read and write system and user preferences. It's an abstract class, but you can get appropriate objects using the userNodeForPackage(ClassName.class)and systemNodeForPackage(ClassName.class).
您可能还想查看Preferences类，该类用于读取和写入系统和用户首选项。它是一个抽象类，但您可以使用userNodeForPackage(ClassName.class)and获取适当的对象systemNodeForPackage(ClassName.class)。
回答by JeeBee
The simple way is to simply have a properties file, e.g., myapp.properties, with all your settings in. It's not a very advanced way to do settings but it suffices, or you can have your own XML based setup, or get them from a database, etc.
简单的方法是简单地拥有一个属性文件，例如 myapp.properties，其中包含所有设置。这不是一种非常高级的设置方法，但它就足够了，或者您可以拥有自己的基于 XML 的设置，或者从数据库等
回答by Pursuit
To put @Powerlord's suggestion (+1) of using the Propertiesclass into example code:
将@Powerlord 使用Properties该类的建议 (+1)放入示例代码中：
public class SomeClass {
public static void main(String[] args){
String dbUrl = "";
String dbLogin = "";
String dbPassword = "";
if (args.length<3) {
//If no inputs passed in, look for a configuration file
URL configFile = SomeClass.class.getClass().getResource("/Configuration.cnf");
try {
InputStream configFileStream = configFile.openStream();
Properties p = new Properties();
p.load(configFileStream);
configFileStream.close();
dbUrl = (String)p.get("dbUrl");
dbLogin = (String)p.get("dbUser");
dbPassword = (String)p.get("dbPassword");
} catch (Exception e) { //IO or NullPointer exceptions possible in block above
System.out.println("Useful message");
System.exit(1);
}
} else {
//Read required inputs from "args"
dbUrl = args[0];
dbLogin = args[1];
dbPassword = args[2];
}
//Input checking one three items here
//Real work here.
}
}
Then, at the root of the container (e.g. top of a jar file) place a file Configuration.cnfwith the following content:
然后，在容器的根目录（例如 jar 文件的顶部）放置一个Configuration.cnf包含以下内容的文件：
#Comments describing the file
#more comments
dbUser=username
dbPassword=password
dbUrl=jdbc\:mysql\://servername/databasename
This feel not perfect (I'd be interested to hear improvements) but good enough for my current needs.
这感觉并不完美（我有兴趣听到改进）但足以满足我当前的需求。
