@Profile註解與@Conditional註解

@Profile註解：是spring爲咱們提供的能夠根據當前環境，動態的激活和切換一系列組件的功能。

@Conditional：按照必定的條件進行判斷，知足條件則給容器中注入bean

@Profile代碼示例：

package common.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.EmbeddedValueResolverAware;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Profile;
import org.springframework.context.annotation.PropertySource;
import org.springframework.util.StringValueResolver;

import javax.sql.DataSource;

@Configuration
@PropertySource("classpath:/dbconfig.properties")
public class MainConfigProfile implements EmbeddedValueResolverAware {
    @Value("${db.username}")
    private String userName;

    private StringValueResolver valueResolver;

    private String driver;

    @Profile("dev")
    @Bean("devDataSource")
    public DataSource dataSourceDev(@Value("${db.password}")String pwd){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUsername(userName);
        dataSource.setPassword(pwd);
        dataSource.setUrl("dbc:mysql://localhost:3306/dev");
        dataSource.setDriverClassName(driver);
        return dataSource;
    }

    @Profile("test")
    @Bean("testDataSource")
    public DataSource dataSourceTest(@Value("${db.password}")String pwd){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUsername(userName);
        dataSource.setPassword(pwd);
        dataSource.setUrl("dbc:mysql://localhost:3306/test");

        dataSource.setDriverClassName(driver);
        return dataSource;
    }

    @Profile("prod")
    @Bean("prodDataSource")
    public DataSource dataSourceProd(@Value("${db.password}")String pwd){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUsername(userName);
        dataSource.setPassword(pwd);
        dataSource.setUrl("dbc:mysql://localhost:3306/prod");
        dataSource.setDriverClassName(driver);
        return dataSource;
    }

    @Override
    public void setEmbeddedValueResolver(StringValueResolver resolver) {
        this.valueResolver = resolver;
        driver = valueResolver.resolveStringValue("${db.driverClass}");
    }
}

測試類：

package common;

import common.config.MainConfigProfile;
import org.junit.Test;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class ProFileTest {

    //1.使用命令行動態參數: 在虛擬機參數位置加載 -Dspring.profiles.active=test
    //二、代碼的方式激活某種環境；
    @Test
    public void test(){
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MainConfigProfile.class);
//        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
//        context.getEnvironment().setActiveProfiles("dev");
//        context.register(MainConfigProfile.class);
//        context.refresh();

        String[] names = context.getBeanDefinitionNames();
        for (String s: names){
            System.out.println(s);
        }
    }
}

測試結果的輸出能夠看出使用了@Profile註解後，能夠指定組件在哪一個環境的狀況下才能被註冊到容器中，不指定，任何環境都能註冊這個組件。

@Condition示例

配置類：

package common.config;

import common.bean.Red;
import common.bean.Yellow;
import condition.WindowsCondition;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;

/**
 * @Conditional註解加在配置類上，不知足條件時，配置類都不會注入到容器中
 */
@Configuration
public class MainConfigCondition {

    @Bean
    public Red red(){
        return new Red();
    }
    @Conditional(WindowsCondition.class)
    @Bean
    public Yellow yellow(){
        return new Yellow();
    }
}

 

package condition;

import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.env.Environment;
import org.springframework.core.type.AnnotatedTypeMetadata;

public class WindowsCondition implements Condition {
    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
        Environment environment = context.getEnvironment();
        String property = environment.getProperty("os.name");
        if(property.contains("Windows")){
            return false;
        }
        return true;
    }
}

測試類：

package common;

import common.config.MainConfigCondition;
import common.config.MainConfigProfile;
import org.junit.Test;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class ProFileTest {

    @Test
    public void test(){
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MainConfigCondition.class);
        String[] names = context.getBeanDefinitionNames();
        for (String s: names){
            System.out.println(s);
        }
    }
}

測試結果：

八月 29, 2018 4:11:43 下午 org.springframework.context.annotation.AnnotationConfigApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@2a3046da: startup date [Wed Aug 29 16:11:43 CST 2018]; root of context hierarchy
org.springframework.context.annotation.internalConfigurationAnnotationProcessor
org.springframework.context.annotation.internalAutowiredAnnotationProcessor
org.springframework.context.annotation.internalRequiredAnnotationProcessor
org.springframework.context.annotation.internalCommonAnnotationProcessor
org.springframework.context.event.internalEventListenerProcessor
org.springframework.context.event.internalEventListenerFactory
mainConfigCondition
red