fix: 处理连接池为空的情况

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

@@ -35,8 +35,10 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR:" + e.getMessage(), e);
         } finally {
+            if(connection != null){
                 connection.close();
             }
+        }
         return list;
     }
 
@@ -52,9 +54,11 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR:" + e.getMessage(), e);
         } finally {
+            if(connection != null){
                 connection.close();
             }
         }
+    }
 
     @Override
     public List<String[]> fetchResult(DatasourceRequest datasourceRequest) throws Exception {
@@ -70,9 +74,11 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR:" + e.getMessage(), e);
         } finally {
+            if(connection != null){
                 connection.close();
             }
         }
+    }
 
     private List<String[]> fetchResult(ResultSet rs) throws Exception {
         List<String[]> list = new LinkedList<>();
@@ -110,9 +116,11 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR:" + e.getMessage(), e);
         } finally {
+            if(connection != null){
                 connection.close();
             }
         }
+    }
 
     @Override
     public Map<String, List> fetchResultAndField(DatasourceRequest datasourceRequest) throws Exception {
@@ -135,9 +143,11 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR:" + e.getMessage(), e);
         } finally {
+            if(connection != null){
                 connection.close();
             }
         }
+    }
 
     private List<TableFiled> fetchResultField(ResultSet rs) throws Exception {
         List<TableFiled> fieldList = new ArrayList<>();
@@ -175,9 +185,11 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR: " + e.getMessage(), e);
         } finally {
+            if(con != null){
                 con.close();
             }
         }
+    }
 
     @Override
     public List<TableFiled> getTableFileds(DatasourceRequest datasourceRequest) throws Exception {
@@ -214,8 +226,10 @@ public class JdbcProvider extends DatasourceProvider {
         } catch (Exception e) {
             throw new Exception("ERROR:" + e.getMessage(), e);
         } finally {
+            if(connection != null){
                 connection.close();
             }
+        }
         return list;
     }