java .properties 文件中的条件语句
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/10899910/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
conditional statement in .properties file
提问by Piyush
Is there a way we can have conditional statement inside a .propertiesfile?
有没有办法在.properties文件中包含条件语句？
like:
喜欢：
if(condition1)
xyz = abc
else if(condition2)
xyz = efg
回答by Jigar Joshi
NoThere is no such conditional statement in properties file, May be you would write a wrapper over Propertiesto encapsulate your logic
否属性文件中没有这样的条件语句，可能您会编写一个包装器Properties来封装您的逻辑
Example:
例子：
class MyProperties extends Properties {
/**
*
*
*
* @param key
* @param conditionalMap
* @return
*/
public String getProperty(String key, List<Decision> decisionList) {
if (decisionList == null) {
return getProperty(key);
}
Long value = Long.parseLong(getProperty(key));
for (Decision decision : decisionList) {
if (Condition.EQUALS == decision.getCondition() && decision.getValue().equals(value)) {
return getProperty(decision.getTargetKey());
}
}
return super.getProperty(key);
}
}
and
和
enum Condition {
EQUALS, GREATER, LESSER
}
and
和
class Decision {
Condition condition;
String targetKey;
Long value;
//accessor
public Condition getCondition() {
return condition;
}
public void setCondition(Condition condition) {
this.condition = condition;
}
public String getTargetKey() {
return targetKey;
}
public void setTargetKey(String targetKey) {
this.targetKey = targetKey;
}
}
so now for example if you want to read the properties file, get category of age, if it is greater than 0 and less than 10 read kid
所以现在例如如果你想读取属性文件，获取年龄类别，如果它大于 0 且小于 10 读取 kid
so may be you could pass the list of such conditions,
所以也许你可以通过这些条件的列表，
note: This design can go under much improvement (not good design), it is just to illustrate how to wrap properties and add stuff that OP wants
注意：这个设计可以有很大的改进（不是好的设计），它只是为了说明如何包装属性和添加 OP 想要的东西
回答by JB Nizet
No, it's not possible. The file format is freely available: http://docs.oracle.com/javase/6/docs/api/java/util/Properties.html#load%28java.io.Reader%29.
不，这不可能。文件格式可免费获得：http: //docs.oracle.com/javase/6/docs/api/java/util/Properties.html#load%28java.io.Reader%29。
Do this in Java code:
在 Java 代码中执行此操作：
if (condition1) {
return properties.getProperty("xyz.1");
}
else if (condition2) {
return properties.getProperty("xyz.2");
}
回答by duffymo
If your problem is different properties for different environments (e.g. devl, test, perf, prod), the common solution is a different version of the properties file for each environment. Communicate environment info to your app and look for a file with the correct name appended to the file name.
如果您的问题是针对不同环境（例如 devl、test、perf、prod）的不同属性，常见的解决方案是针对每个环境使用不同版本的属性文件。将环境信息传达给您的应用程序，并查找在文件名后附加了正确名称的文件。
Something like this for Spring:
春天的事情是这样的：
Environment-specific configuration for a Spring-based web application?
回答by user949300
As @Jigar said, there is no conditional logic in a properties file. But you could have two lines in there, e.g. something like:
正如@Jigar 所说，属性文件中没有条件逻辑。但是你可以在那里有两行，例如：
xyz.condition1 = abs
xyz.condition2 = efg
and, in your code to access the property, append the proper condition to the key.
并且，在您访问该属性的代码中，将正确的条件附加到密钥。
回答by Alessandro
this is the way:
这是方法：
xyz[condition1]=abs
xyz[condition2]=efg
