今天接手一個專案，專案中使用SpringBoot，發現之前實現Beetl自定義標籤註冊的方式有些傻大粗，做了些修改，整理之後釋出，作為回顧。

Beetl自定義標籤

下面說一下在SpringBoot中關於Beetl自定義標籤的定義以及注入：

1. 自定義標籤需要繼承 org.beetl.core.Tag 類，在 render() 方法中進行標籤功能實現；

2. 標籤註冊

   /**
    * Beetl配置類
    */
   @Configuration
   public class BeetlConfiguration {
       @Bean(initMethod = "init", name = "beetlConfig"
    
   )
       public BeetlGroupUtilConfiguration getBeetlConfig() {
           BeetlGroupUtilConfiguration beetlGroupUtilConfiguration = new BeetlGroupUtilConfiguration();
   
           // 1.單個標籤註冊
           beetlGroupUtilConfiguration.getGroupTemplate().registerTag("myTag", FindListTag.class);
   
           // 2.通過Spring Bean方式註冊
    
   
           SpringBeanTagFactory tagFactory = new SpringBeanTagFactory();
           // 此處使用的name為Spring中註冊的Bean的name
           tagFactory.setName("myTag");
           beetlGroupUtilConfiguration.getGroupTemplate().registerTagFactory("myTag", tagFactory);
   
           // 3.多標籤註冊
           SpringBeanTagFactory tag1 = new
    
    SpringBeanTagFactory();
           tag1.setName("myTag1");
           SpringBeanTagFactory tag2 = new SpringBeanTagFactory();
           tag2.setName("myTag2");
   
           Map<String, TagFactory> tags = new HashMap<>();
           tags.put("myTag1", tag1);
           tags.put("myTag2", tag2);
   
           beetlGroupUtilConfiguration.setTagFactorys(tags);
   
           return beetlGroupUtilConfiguration;
       }
   }

多個自定義標籤整合優化

由上節可以看出，當專案中需要自定義多個標籤時，Beetl配置類中需要反覆的新增標籤進行註冊。

1. 方便管理多個標籤，並且避免汙染Beetl配置類，於是將 Map<String, TagFactory> 使用Spring IoC進行管理注入

   /**
    * Beetl配置類
    */
   @Configuration
   public class BeetlConfiguration {
       @Bean(initMethod = "init", name = "beetlConfig")
       public BeetlGroupUtilConfiguration getBeetlConfig(@Qualifier("tagFactorys") Map<String, TagFactory> tagFactorys) {
           BeetlGroupUtilConfiguration beetlGroupUtilConfiguration = new BeetlGroupUtilConfiguration();
           beetlGroupUtilConfiguration.setTagFactorys(tagFactorys);
           return beetlGroupUtilConfiguration;
       }
   }

2. 配置TagFactory管理類

   @Component
   public class BeetlTagFactoryManager {
       @Bean(name = "tagFactorys")
       public Map<String, TagFactory> tagFactorys() {
           Map<String, TagFactory> tags = new HashMap<>();
           return tags;
       }
   }

   此時，如果專案中的多個自定義標籤並未加入到標籤工廠中

3. 獲取Spring中所有自定義標籤，並且注入到標籤工廠中

   @Component
   public class BeetlTagFactoryManager implements ApplicationContextAware {
       private ApplicationContext applicationContext;
   
       @Override
       public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
           this.applicationContext = applicationContext;
       }
   
       @Bean(name = "tagFactorys")
       public Map<String, TagFactory> tagFactorys() {
           Map<String, TagFactory> tags = new HashMap<>();
           Map<String, Tag> beans = applicationContext.getBeansOfType(Tag.class);
           for (String beanName : beans.keySet()) {
               tags.put(beanName, toSpringBeanTagFactory(beanName));
           }
           return tags;
       }
   
       private SpringBeanTagFactory toSpringBeanTagFactory(String beanName) {
           SpringBeanTagFactory springBeanTagFactory = new SpringBeanTagFactory();
           springBeanTagFactory.setName(beanName);
           return springBeanTagFactory;
       }
   }

4. 至此，自定義標籤注入已經完成。不過，又如何完成標籤的自定義呢？請看下節~~

使用註解進行自定義Beetl標籤名

1. Beetl本身並沒有提供自定義標籤名的註解，所以需要我們自己進行定義

   /**
    * Annotation - Beetl自定義標籤命名
    */
   @Target({ElementType.TYPE})
   @Retention(RetentionPolicy.RUNTIME)
   public @interface BeetlTagName {
       /**
        * 標籤名稱
        */
       String value() default "";
   }

2. 在自定義標籤上加上剛剛建立的註解

   import org.beetl.core.GeneralVarTagBinding;
   import org.springframework.context.annotation.Scope;
   import org.springframework.stereotype.Service;
   
   @Service
   @Scope("prototype")
   @BeetlTagName("my_tag")
   public class MyTag extends GeneralVarTagBinding {
       @Override
       public void render() {
           // TODO 標籤處理
       }
   }

   注： org.beetl.core.GeneralVarTagBinding 是 org.beetl.core.Tag 的一個更友好的抽象實現類。在Beetl模板中使用時，標籤名為 @BeetlTagName 中的所寫，此處為 my_tag。使用方法如下：

   <#my_tag>
       <!--標籤處理-->
   </#my_tag>

3. 修改 BeetlTagFactoryManager ，讀取自定義標籤名

   @Component
   public class BeetlTagFactoryManager implements ApplicationContextAware {
       private ApplicationContext applicationContext;
   
       @Override
       public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
           this.applicationContext = applicationContext;
       }
   
       @Bean(name = "tagFactorys")
       public Map<String, TagFactory> tagFactorys() {
           Map<String, TagFactory> tags = new HashMap<>();
           Map<String, Tag> beans = applicationContext.getBeansOfType(Tag.class);
           for (String beanName : beans.keySet()) {
               // 讀取自定義標籤名
               BeetlTagName tagAnno = beans.get(beanName).getClass().getAnnotation(BeetlTagName.class);
               String tagName = tagAnno != null ? tagAnno.value() : beanName;
               tags.put(tagName, toSpringBeanTagFactory(beanName));
           }
           return tags;
       }
   
       private SpringBeanTagFactory toSpringBeanTagFactory(String beanName) {
           SpringBeanTagFactory springBeanTagFactory = new SpringBeanTagFactory();
           springBeanTagFactory.setName(beanName);
           return springBeanTagFactory;
       }
   }

4. 建立新的自定義標籤時，只需要在標籤上加入 @BeetlTagName 並且寫上你喜歡的標籤名即可使用。至此，大功告成啦~快去體驗吧！