第3章—高级装配—配置profile bean

配置profile bean

3.1.@profile注解是spring提供的一个用来标明当前运行环境的注解。

我们正常开发的过程中经常遇到的问题是，开发环境是一套环境，qa测试是一套环境，线上部署又是一套环境。这样从开发到测试再到部署，会对程序中的配置修改多次，尤其是从qa到上线这个环节，让qa的也不敢保证改了哪个配置之后能不能在线上运行。

为了解决上面的问题，我们一般会使用一种方法，就是配置文件，然后通过不同的环境读取不同的配置文件，从而在不同的场景中跑我们的程序。

那么，spring中的@profile注解的作用就体现在这里。在spring使用DI来依赖注入的时候，能够根据当前制定的运行环境来注入相应的bean。最常见的就是使用不同的DataSource了。

下面详细的介绍一下，如何通过spring的@profile注解实现上面的功能。

创建一个Maven项目,其中的配置如下:

pom.xml:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.home</groupId>
  <artifactId>ProfileTest</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>ProfileTest Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
      <springframework.version>4.3.7.RELEASE</springframework.version>
  </properties>
  <dependencies>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>${springframework.version}</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-test -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>${springframework.version}</version>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.junit.jupiter</groupId>
      <artifactId>junit-jupiter-api</artifactId>
      <version>RELEASE</version>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>compile</scope>
    </dependency>
  </dependencies>

  <build>
    <finalName>ProfileTest</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.0.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.7.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.20.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

App:

package com.hom.demo;

import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

/**
 * Hello world!
 // */
@Configuration
@ComponentScan(basePackages = {"com.hom.demo"})
public class App {
    public static void main(String[] args) {
        ConfigurableApplicationContext context = new AnnotationConfigApplicationContext(com.hom.demo.App.class);
        Person p = context.getBean(Person.class);
        p.speak();
    }
}

接口MoveFactor:

package com.hom.demo;
public interface MoveFactor {
    void speak();
}

Chines:

package com.hom.demo;

import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Profile;
import org.springframework.stereotype.Component;

@Configuration
@Profile(value = "dev")
@Component
public class Chinese implements MoveFactor {
    @Override
    public void speak() {
        System.out.println("我是中国人");
    }
}

English:

package com.hom.demo;

import org.springframework.context.annotation.Profile;
import org.springframework.stereotype.Component;

@Component
@Profile("qa")
public class English implements MoveFactor{
    @Override
    public void speak() {
        System.out.println("i am an English");
    }
}

German:

package com.hom.demo;
import org.springframework.context.annotation.Profile;
import org.springframework.stereotype.Component;
@Component
@Profile("prod")
public class German implements MoveFactor{
    @Override
    public void speak() {
        System.out.println("i am a German");
    }
}

Person:

package com.hom.demo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component
public class Person {
    @Autowired
    private MoveFactor moveFactor;
    public void speak(){
        moveFactor.speak();
    }
}

SpringTest:

package com.hom.demo;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ActiveProfiles;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = App.class)
@ActiveProfiles("dev")
public class SpringTest {
    @Autowired
    Person p;
    @Test
    public void testProfile(){
        p.speak();
    }
}

运行后的结果如下:

当修改@ActiveProfile中的值时，输出的内容也会随之改变。

如果使用的是main函数进行真正的开发、测试和上线时，我们需要设置一下运行参数：

-Dspring.profiles.active=prod

3.2.XML中配置profile

application.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
			http://www.springframework.org/schema/beans/spring-beans-4.3.xsd"
           profile="dev">

<bean id="chinese" class="com.hom.demo.Chinese"></bean>

</beans>

我们还可以在<beans>中嵌套定义<beans>元素,而不是为没个环境都创建一个profile.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
			http://www.springframework.org/schema/beans/spring-beans-4.3.xsd"
      >
<beans profile="dev"> <!--这里可以指定需要的profile名-->
<bean id="chinese" class="com.hom.demo.Chinese"></bean>
</beans>
<beans profile="qa">
<bean id="english" class="com.hom.demo.English"></bean>
</beans>
</beans>

3.3.激活profile

​ Spring在确定那个profile处于激活状态时,需要依赖两个独立的属性:

spring.Profile.active(激活的Profile)

spring.Profile.default(默认的Profile)

这里有多种方式来设置这两个属性:

• 作为DispathServlet的初始参数
• 作为Web应用的上下文参数
• 作为JNDI条目
• 作为环境变量
• 作为JVM的系统属性
• 在集成测试类上,使用@ActiveProfile注解设置

我所喜欢的一种方式是使用DispatcherServlet的参数将spring.rpofiles.default设置开发环境的Profile,我会在Servlet上下文中配置,如下所示:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0" id="WebApp_1525601902125">
  <display-name>Archetype Created Web Application</display-name>
																				  <context-param>
    <param-name>contextConfigLoacation</param-name>
    <param-value>application.xml</param-value>
  </context-param>
  <!--为上下文设置默认的profile-->
<context-param>
  <param-name>spring.rpofiles.default</param-name>
  <param-value>dev</param-value>
</context-param>

  <listener>
    <listener-class>  org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>

    <!--为Servlet设置默认的profile-->
<servlet>
    <servlet-name>appServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>spring.rpofiles.default</param-name>
        <param-value>dev</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>
    <servlet-mapping>
        <servlet-name>appServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

Spring提供了@ActiveProfile注解设置激活状态