加上 synchronized 減少資料庫查詢次數

src/main/java/org/ylhealth/ym/springtest/hibernate/I18NReadEventListener.java

@@ -22,6 +22,8 @@ import org.slf4j.LoggerFactory;
 import org.springframework.context.i18n.LocaleContextHolder;
 import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
+import com.google.common.collect.Interner;
+import com.google.common.collect.Interners;
 
 /** */
 public class I18NReadEventListener implements PostLoadEventListener {
@@ -32,6 +34,8 @@ public class I18NReadEventListener implements PostLoadEventListener {
 
   private SessionFactoryImplementor sessionFactory;
 
+  private Interner<String> pool = Interners.newWeakInterner();
+
   @SuppressWarnings("rawtypes")
   private Cache<String, Map> cache =
       CacheBuilder.newBuilder().expireAfterAccess(1, TimeUnit.MINUTES).build();
@@ -80,7 +84,7 @@ public class I18NReadEventListener implements PostLoadEventListener {
    * @throws InvocationTargetException
    */
   private Map<String, String> getTranslate(
-      StatelessSession session, I18NTranslates i18n, Object entity, Class clazz)
+      StatelessSession session, I18NTranslates i18n, Object entity, @SuppressWarnings("rawtypes") Class clazz)
       throws IllegalAccessException, InvocationTargetException {
     Object id = getPKValue(clazz, entity);
     String language = LocaleContextHolder.getLocale().toString();
@@ -93,6 +97,7 @@ public class I18NReadEventListener implements PostLoadEventListener {
     return translateTable.get(id);
   }
 
+  @SuppressWarnings("unchecked")
   private Map<String, Map<String, String>> translateTable(
       StatelessSession session,
       String table,
@@ -102,25 +107,33 @@ public class I18NReadEventListener implements PostLoadEventListener {
     String key = "Table:" + table + "_" + language;
     Map<String, Map<String, String>> result = cache.getIfPresent(key);
     if (result == null) {
-      logger.trace("translate query, table: {}", table);
-      String sql = String.format("select * from %s where languageCode = ?", table);
-      SQLQuery query1 = session.createSQLQuery(sql);
-      query1.setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP);
-      query1.addScalar(idColumn);
-      for (I18NTranslate i18nTranslate : mapping) {
-        query1.addScalar(i18nTranslate.column());
-      }
-      query1.setParameter(0, language);
-      List<Map<String, String>> result1 = query1.list();
-      result = new HashMap<>();
-      for (Map<String, String> map : result1) {
-        result.put(map.get(idColumn), map);
+      synchronized (pool.intern(key)) {
+        result = cache.getIfPresent(key);
+        if (result == null) {
+          logger.trace("translate query, table: {}", table);
+          String sql = String.format("select * from %s where languageCode = ?", table);
+          SQLQuery query1 = session.createSQLQuery(sql);
+          query1.setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP);
+          query1.addScalar(idColumn);
+          query1.addScalar("languageCode");
+          for (I18NTranslate i18nTranslate : mapping) {
+            query1.addScalar(i18nTranslate.column());
+          }
+          query1.setParameter(0, language);
+          List<Map<String, String>> result1 = query1.list();
+          result = new HashMap<>();
+          for (Map<String, String> map : result1) {
+            map.remove("languageCode");
+            result.put(map.get(idColumn), map);
+          }
+          cache.put(key, result);
+        }
       }
-      cache.put(key, result);
     }
     return result;
   }
 
+
   private Object getPKValue(Class<?> clazz, Object entity)
       throws IllegalArgumentException, IllegalAccessException, InvocationTargetException {
     Collection<Field> fields = getAllDeclaredFields(clazz);
@@ -132,29 +145,11 @@ public class I18NReadEventListener implements PostLoadEventListener {
     }
     for (Method method : clazz.getDeclaredMethods()) {
       if (method.getAnnotation(Id.class) != null) {
-        return method.invoke(entity, null);
+        return method.invoke(entity);
       }
     }
     return null;
   }
-  /**
-   * Returns the entity's @{@link I18NTranslate} fields.
-   *
-   * <p>These fields are made accessible.
-   */
-  private static Collection<Field> getLocalizedFields(Class<?> clazz) {
-    Collection<Field> fields = getAllDeclaredFields(clazz);
-    List<Field> localizedFields = new ArrayList<>();
-    fields
-        .stream()
-        .filter(field -> field.getAnnotation(I18NTranslate.class) != null)
-        .forEach(
-            field -> {
-              field.setAccessible(true);
-              localizedFields.add(field);
-            });
-    return localizedFields;
-  }
 
   private static Collection<Field> getAllDeclaredFields(Class<?> clazz) {
     List<Field> fields = new ArrayList<>();