spring中@Profile的作用

根据系统环境的不同，Profile可以用来切换数据源。例如切换开发，测试，生产环境的数据源。

举个例子：

先创建配置类MainProfileConfig：

@Configuration
@PropertySource("classpath:/jdbc.properties")
public class MainProfileConfig implements EmbeddedValueResolverAware {
 
    @Value("${db.user}")
    private String user;
 
    private String driverClass;
 
    private StringValueResolver stringValueResolver;
 
    @Profile("test")
    @Bean("testDataSource")
    public  DataSource getTestDataSource(@Value("${db.password}") String pwd) throws PropertyVetoException {
        ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
        comboPooledDataSource.setUser(user);
        comboPooledDataSource.setPassword(pwd);
        comboPooledDataSource.setDriverClass(driverClass);
        return comboPooledDataSource;
    }
 
    @Profile("dev")
    @Bean("devDataSource")
    public  DataSource getDevDataSource(@Value("${db.password}") String pwd) throws PropertyVetoException {
        ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
        comboPooledDataSource.setUser(user);
        comboPooledDataSource.setPassword(pwd);
        comboPooledDataSource.setDriverClass(driverClass);
        return comboPooledDataSource;
    }
 
    @Profile("pro")
    @Bean("proDataSource")
    public  DataSource getproDataSource(@Value("${db.password}") String pwd) throws PropertyVetoException {
        ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
        comboPooledDataSource.setUser(user);
        comboPooledDataSource.setPassword(pwd);
        comboPooledDataSource.setDriverClass(driverClass);
        return comboPooledDataSource;
    }
 
    @Override
    public void setEmbeddedValueResolver(StringValueResolver stringValueResolver) {
        this.stringValueResolver = stringValueResolver;
        driverClass = stringValueResolver.resolveStringValue("${db.driverClass}");
    }
}

这里使用@Value和StringValueResolver来给属性赋值

测试：运行的时候设置环境   -Dspring.profiles.active=dev

public class ProFileTest {
 
    @Test
    public void  test(){
        AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(MainProfileConfig.class);
 
        String[] beanNamesForType = applicationContext.getBeanNamesForType(DataSource.class);
        for (String name : beanNamesForType){
            System.out.println(name);
        }
        applicationContext.close();
    }
}

打印输出：

devDataSource

也可以使用代码的方式设置系统环境，创建容器的时候使用无参构造方法，然后设置属性。

@Test
    public void  test(){
        //创建容器
        AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext();
        //设置需要激活的环境
        applicationContext.getEnvironment().setActiveProfiles("test");
        //设置主配置类
        applicationContext.register(MainProfileConfig.class);
        //启动刷新容器
        applicationContext.refresh();
 
        String[] beanNamesForType = applicationContext.getBeanNamesForType(DataSource.class);
        for (String name : beanNamesForType){
            System.out.println(name);
        }
        applicationContext.close();
    }

打印输出：

testDataSource

setActiveProfiles设置环境的时候可以传入多个值，它的方法可以接受多个参数。

public interface ConfigurableEnvironment extends Environment, ConfigurablePropertyResolver {
    void setActiveProfiles(String... var1);