文章目錄

• 7.高階裝配(一)
• 1. 環境與Profile
• 1.解決不同環境不同配置
• 2.配置方式
• 2. 條件化bean
• 1. 概念
• 2. 舉例

7.高階裝配(一)

1. 環境與Profile

1.解決不同環境不同配置

1. maven構建時，使用profiles來確定將哪一個配置編譯到可部署的應用
   1. 缺點：不同環境重新構建，可能引入bug
2. 使用Spring profile

2.配置方式

1. Java

   1. 可以放在類上和方法上，類上的級別會覆蓋方法上的，放在類級別上，表示該型別所有的bean都受此影響

      package com.desmond.springlearning.profiles;
      
      import com.desmond.springlearning.profiles.vo.Person;
      import org.springframework.context.annotation.Bean;
      import org.springframework.context.annotation.Configuration;
      import org.
       
      springframework.context.annotation.Profile;
      
      /**
       * Created by presleyli on 2018/4/6.
       */
      @Configuration
      @Profile("dev")
      public class ConfigurationConfig {
      
          @Bean
          @Profile("prod")
          public Person getProdPerson() {
              Person person = new Person();
              person.setName("prod");
      
              return
       
       person;
          }
      
          @Bean
          public String name() {
              return "prod";
          }
      
          @Bean
          @Profile("test")
          public Person getTestPerson() {
              Person person = new Person();
              person.setName("test");
      
              return person;
          }
      
          @Bean
          @Profile("dev")
          public Person getDevPerson() {
              Person person = new Person();
              person.setName("dev");
      
              return person;
          }
      }
      
      

   2. JVM配置 引數 -Dspring.profiles.default=dev

2. XML

   1. xml中只能放在上

   2. 程式碼

      <?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.xsd">
      
          <beans profile="prod">
              <bean id="person" class="com.desmond.springlearning.profiles.vo.Person">
                  <constructor-arg value="prod" />
              </bean>
          </beans>
      
          <beans profile="test">
              <bean id="testPerson" class="com.desmond.springlearning.profiles.vo.Person">
                  <constructor-arg value="test"/>
              </bean>
          </beans>
      
          <beans profile="dev">
              <bean id="devPerson" class="com.desmond.springlearning.profiles.vo.Person">
                  <constructor-arg value="dev"/>
              </bean>
          </beans>
      </beans>
      

      2. JVM配置 引數 -Dspring.profiles.default=dev

      3. 測試類

         package com.desmond.springlearning.profiles;
         
         import com.desmond.springlearning.profiles.vo.Person;
         import org.springframework.context.ApplicationContext;
         import org.springframework.context.annotation.AnnotationConfigApplicationContext;
         import org.springframework.context.support.ClassPathXmlApplicationContext;
         
         /**
          * @author presleyli
          * @date 2018/10/9 下午10:15
          */
         public class XmlTest {
             public static void main(String[] args) {
                 ApplicationContext context = new ClassPathXmlApplicationContext("profiles/config.xml");
         
                 Person person = context.getBean(Person.class);
         
                 System.out.println(person.getName());
             }
         }
         
         

   3. 啟用 profile

      1. 須依賴兩個屬性 spring.profiles.active和 spring.profiles.default, 如果設定了active, 先用active；否使用default. 如果兩者均未設定，則無啟用的profile, 也就只加載哪些沒有定義在profile裡的bean.
      2. 多種方式設定這兩個屬性
         1. DispatcherServlet 初始化引數
         2. Web應用上下文
         3. JNDI
         4. 環境變數
         5. JVM 變數 eg. -Dspring.profiles.default=dev
         6. 在整合測試類上，使用註解 @ActiveProfiles

2. 條件化bean

1. 概念

當一個或者多個bean需要遇到特定條件才建立

2. 舉例

1. 假設當Person類，當環境中設定人名為Tom時，才認為此人標籤為牛掰

2. 首先，定義一個條件類，實現Condition介面

   package com.desmond.springlearning.conditional;
   
   import org.springframework.context.annotation.Condition;
   import org.springframework.context.annotation.ConditionContext;
   import org.springframework.core.type.AnnotatedTypeMetadata;
   
   /**
    * @author presleyli
    * @date 2018/10/9 下午10:55
    */
   public class PersonCondition implements Condition{
       public boolean matches(ConditionContext conditionContext, AnnotatedTypeMetadata annotatedTypeMetadata) {
           String name = conditionContext.getEnvironment().getProperty("name");
   
           return "Tom".equalsIgnoreCase(name);
       }
   }
   
   

   3. 定義configuration

   package com.desmond.springlearning.conditional;
   
   /**
    * @author presleyli
    * @date 2018/10/9 下午10:53
    */
   
   import org.springframework.context.annotation.Bean;
   import org.springframework.context.annotation.Conditional;
   import org.springframework.context.annotation.Configuration;
   
   @Configuration
   public class ConConfiguration {
       @Bean
       @Conditional(PersonCondition.class)
       public Person person() {
           Person person = new Person();
   
           person.setNotes("此人牛掰.");
   
           return person;
       }
   }
   
   

3. Person

   package com.desmond.springlearning.conditional;
   
   import lombok.Data;
   
   /**
    * @author presleyli
    * @date 2018/10/9 下午10:52
    */
   @Data
   public class Person {
       public String notes;
   }
   
   

4. 測試

   package com.desmond.springlearning.conditional;
   
   import org.springframework.context.ApplicationContext;
   import org.springframework.context.annotation.AnnotationConfigApplicationContext;
   
   /**
    * @author presleyli
    * @date 2018/10/9 下午10:15
    */
   public class AnnoCondTest {
       public static void main(String[] args) {
           ApplicationContext context = new AnnotationConfigApplicationContext(ConConfiguration.class);
   
           Person person = context.getBean(Person.class);
   
           System.out.println(person.getNotes());
       }
   }
   
   

5. 新增環境變數 name=Tom

6. 結果
   此人牛掰. 否則找不到bean:

   Exception in thread "main" org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.desmond.springlearning.conditional.Person' available
   

7. 從4.0 @Profile也使用此法：

   1. 註解

      //
      // Source code recreated from a .class file by IntelliJ IDEA
      // (powered by Fernflower decompiler)
      //
      
      package org.springframework.context.annotation;
      
      import java.lang.annotation.Documented;
      import java.lang.annotation.ElementType;
      import java.lang.annotation.Retention;
      import java.lang.annotation.RetentionPolicy;
      import java.lang.annotation.Target;
      
      @Target({ElementType.TYPE, ElementType.METHOD})
      @Retention(RetentionPolicy.RUNTIME)
      @Documented
      
      @Conditional({ProfileCondition.class}) // 條件
      
      public @interface Profile {
          String[] value();
      }
      
      

   2. condition

      /*
       * Copyright 2002-2013 the original author or authors.
       *
       * Licensed under the Apache License, Version 2.0 (the "License");
       * you may not use this file except in compliance with the License.
       * You may obtain a copy of the License at
       *
       *      http://www.apache.org/licenses/LICENSE-2.0
       *
       * Unless required by applicable law or agreed to in writing, software
       * distributed under the License is distributed on an "AS IS" BASIS,
       * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
       * See the License for the specific language governing permissions and
       * limitations under the License.
       */
      
      package org.springframework.context.annotation;
      
      import org.springframework.core.type.AnnotatedTypeMetadata;
      import org.springframework.util.MultiValueMap;
      
      /**
       * {@link Condition} that matches based on the value of a {@link Profile @Profile}
       * annotation.
       *
       * @author Chris Beams
       * @author Phillip Webb
       * @author Juergen Hoeller
       * @since 4.0
       */
      class ProfileCondition implements Condition {
      
      	@Override
      	public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
      		if (context.getEnvironment() != null) {
      			MultiValueMap<String, Object> attrs = metadata.getAllAnnotationAttributes(Profile.class.getName());
      			if (attrs != null) {
      				for (Object value : attrs.get("value")) {
      					if (context.getEnvironment().acceptsProfiles(((String[]) value))) {
      						return true;
      					}
      				}
      				return false;
      			}
      		}
      		return true;
      	}
      
      }