英文:
How an object can be available to all classes in java?
问题
我正在创建一个包含许多Java类的应用程序。为了存储可配置信息，比如用户名、网址、文件路径等，我正在使用resources/app.properties文件。
为了从这个文件中读取值，我正在使用以下代码
InputStream input = new FileInputStream("../resources/app.properties");
Properties prop = new Properties();
prop.load(input);
System.out.println("print the url" + prop.getProperty("username"));
正如我们从代码中可以看到的那样，要从app.properties文件中读取任何属性，我们需要prop对象。
我们是否可以以这样的方式编写代码，即在主类中只需编写前3行一次，然后我们可以在整个应用程序的任何类中调用**prop.getProperty("username")**呢？
英文:
I am creating an application with many java classes. for keeping the configurable information like username, urls', file paths etc, I am using resources/app.properties file.
For reading values from this file, I am using below code
InputStream input = new FileInputStream("../resources/app.properties");
Properties prop = new Properties();
prop.load(input);
System.out.println("print the url" + prop.getProperty("username"));
as we can see from the code, for reading any property from app.properties file, we need prop
object.
can we write this code in such a way that we just need to write first 3 lines once in the code in the main calss and then we can call prop.getProperty("username") from any class in our whole application?
答案1
得分: 1
很简单。
定义配置，如下：
@Configuration
public class TestConfiguration {
@Value("classpath:test.properties")
private Resource resource;
@SneakyThrows // 这是来自 lombok 依赖。你可以处理异常
@Bean
public Properties getProperties() {
Properties properties = new Properties();
properties.load(this.resource.getInputStream());
return properties;
}
}
在需要的地方自动装配这个类。
@Autowired
private TestConfiguration configuration;
使用：this.configuration.getProperties().getProperty("username") 来获取用户名，其他字段也同理。
通过这种方式，你可以实现单例设计模式。
英文:
It's pretty simple.
Define configuration, like
@Configuration
public class TestConfiguration {
@Value("classpath:test.properties")
private Resource resource;
@SneakyThrows // this is from lombok dependency. You can handle exception
@Bean
public Properties getProperties() {
Properties properties = new Properties();
properties.load(this.resource.getInputStream());
return properties;
}
}
Autowire this class wherever you need it.
@Autowired private TestConfiguration configuration;
Use: this.configuration.getProperties().getProperty("username") to get username and same for other fields.
By doing this way, you can achieve a singleton design pattern.
答案2
得分: 0
你可以考虑静态方法...
或者考虑单例模式。
英文:
You could think about static methods...
or maybe think about the singleton pattern.
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