fix(paging item reader): Staying simple and and passing

 all tests locally.

Author: Julien KLAER

src/main/java/org/mybatis/spring/batch/MyBatisPagingItemReader.java

@@ -92,22 +92,11 @@ public void afterPropertiesSet() throws Exception {
     notNull(queryId, "A queryId is required.");
   }
 
-  @Override
-  protected void doOpen() throws Exception {
-    super.doOpen();
-    sqlSessionTemplate = new SqlSessionTemplate(sqlSessionFactory, ExecutorType.BATCH);
-  }
-
-  @Override
-  protected void doClose() throws Exception {
-    if (sqlSessionTemplate != null) {
-      sqlSessionTemplate.close();
-    }
-    super.doClose();
-  }
-
   @Override
   protected void doReadPage() {
+    if (sqlSessionTemplate == null) {
+      sqlSessionTemplate = new SqlSessionTemplate(sqlSessionFactory, ExecutorType.BATCH);
+    }
     Map<String, Object> parameters = new HashMap<>();
     if (parameterValues != null) {
       parameters.putAll(parameterValues);