@PropertySource讀取配置文件經過@Value進行參數注入

有參數文件以下test.properties

project.author=wpfc
project.create_time=2018/3/29

在系統中讀取對應的數據，並注入到屬性中

@Configuration
@ComponentScan("cn.edu.ntu")
@PropertySource("classpath:test.properties")
public class ElConfig {

	@Value("#{systemProperties['os.name']}")
	private String osName;
	
	//要想使用@Value 用${}佔位符注入屬性，這個bean是必須的(PropertySourcesPlaceholderConfigurer)，
    //這個就是佔位bean,
	//另外一種方式是不用value直接用Envirment變量直接getProperty('key')  
	@Value("${project.author}")
	public String author;
    
	@Autowired
	private Environment environment;
	
	//You need this if you use @PropertySource + @Value
    @Bean
    public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
       return new PropertySourcesPlaceholderConfigurer();
    }
	
	public void printProperties(){
		System.out.println("os name : " + osName);
		System.out.println("author  : " + author);
		System.out.println("env     : " + environment.getProperty("project.create_time"));
	}
	
}

測試方法：

public class MainApplication {

	public static void main(String[] args){
		AnnotationConfigApplicationContext context = null;
		context = new AnnotationConfigApplicationContext(ElConfig.class);
		ElConfig bean = context.getBean(ElConfig.class);
		bean.printProperties();
	}
	
}

測試結果：

os name : Windows 7
author  : wpfc
env     : 2018/3/29

@Import  引入javaConfig配置的配置類
@ImportResource   引入xml對應的配置文件