SpringBoot19 之环境变量读取和属性对象的绑定

凡是被Spring管理的类，实现接口 EnvironmentAware 重写方法 setEnvironment 可以在工程启动时，

获取到系 统环境变量和application配置文件中的变量。

@Configuration

public class MyEnvironmentAware implements EnvironmentAware {

//注入application.properties的属性到指定变量中.

@Value("${spring.datasource.url}")

private String myUrl;

@Override

public void setEnvironment(Environment environment) {

//打印注入的属性信息.

System.out.println("myUrl=" + myUrl);

//通过 environment 获取到系统属性.

System.out.println(environment.getProperty("JAVA_HOME"));

//通过 environment 同样能获取到application.properties配置的属性.

System.out.println(environment.getProperty("spring.datasource.url"));

//获取到前缀是"spring.datasource." 的属性列表值.

RelaxedPropertyResolver relaxedPropertyResolver = new RelaxedPropertyResolver(environment, "spring.datasource.");

System.out.println("spring.datasource.url=" + relaxedPropertyResolver.getProperty("url"));

System.out.println("spring.datasource.driverClassName=" + relaxedPropertyResolver.getProperty("driverClassName"));

}

}

@Controller @Service 等被Spring管理的类都支持，注意重写的方法 setEnvironment 是在系统启动的时候被执行。 或者如下Controller:

@Controller

public class PageController implements EnvironmentAware {

@Override

public void setEnvironment(Environment environment) {

String s = environment.getProperty("JAVA_HOME");

System.out.println(s);

}

}