fix: 处理连接池为空的情况

backend/src/main/java/io/dataease/datasource/provider/JdbcProvider.java

@@ -35,7 +35,9 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR:" + e.getMessage(), e);
         } finally {
-            connection.close();
+            if(connection != null){
+                connection.close();
+            }
         }
         return list;
     }
@@ -52,7 +54,9 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR:" + e.getMessage(), e);
         } finally {
-            connection.close();
+            if(connection != null){
+                connection.close();
+            }
         }
     }
 
@@ -70,7 +74,9 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR:" + e.getMessage(), e);
         } finally {
-            connection.close();
+            if(connection != null){
+                connection.close();
+            }
         }
     }
 
@@ -110,7 +116,9 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR:" + e.getMessage(), e);
         } finally {
-            connection.close();
+            if(connection != null){
+                connection.close();
+            }
         }
     }
 
@@ -135,7 +143,9 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR:" + e.getMessage(), e);
         } finally {
-            connection.close();
+            if(connection != null){
+                connection.close();
+            }
         }
     }
 
@@ -175,7 +185,9 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR: " + e.getMessage(), e);
         } finally {
-            con.close();
+            if(con != null){
+                con.close();
+            }
         }
     }
 
@@ -214,7 +226,9 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR:" + e.getMessage(), e);
         } finally {
-            connection.close();
+            if(connection != null){
+                connection.close();
+            }
         }
         return list;
     }