BAEL-4498 JDBC Connection Status

persistence-modules/core-java-persistence-2/src/main/java/com/baeldung/connectionstatus/ConnectionValidation.java

@@ -0,0 +1,65 @@
+package com.baeldung.connectionstatus;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+
+public class ConnectionValidation
+{
+
+    public static Connection getConnection()
+            throws Exception
+    {
+        Class.forName("org.h2.Driver");
+        String url = "jdbc:h2:mem:testdb";
+        return DriverManager.getConnection(url, "user", "password");
+    }
+
+    public static void runIfOpened(Connection connection)
+            throws SQLException
+    {
+        if (connection != null && !connection.isClosed()) {
+            // run sql statements
+        }
+        else {
+            // handle closed connection
+        }
+    }
+
+    public static void runIfValid(Connection connection)
+            throws SQLException
+    {
+        // Try to validate connection with a 5 seconds timeout
+        if (connection.isValid(5)) {
+            // run sql statements
+        }
+        else {
+            // handle invalid connection
+        }
+    }
+
+    public static void runIfConnectionValid(Connection connection)
+    {
+        if (isConnectionValid(connection)) {
+            // run sql statements
+        }
+        else {
+            // handle invalid connection
+        }
+    }
+
+    public static boolean isConnectionValid(Connection connection)
+    {
+        try {
+            if (connection != null && !connection.isClosed()) {
+                // Running a simple validation query
+                connection.prepareStatement("SELECT 1");
+                return true;
+            }
+        }
+        catch (SQLException e) {
+            // log some useful data here
+        }
+        return false;
+    }
+}

persistence-modules/core-java-persistence-2/src/test/java/com/baeldung/connectionstatus/ConnectionValidationUnitTest.java

@@ -0,0 +1,38 @@
+package com.baeldung.connectionstatus;
+
+import org.junit.jupiter.api.Test;
+
+import java.sql.Connection;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class ConnectionValidationUnitTest
+{
+    @Test
+    void givenConnectionObject_whenCreated_thenIsNotClosed()
+            throws Exception
+    {
+        Connection connection = ConnectionValidation.getConnection();
+        assertNotNull(connection);
+        assertFalse(connection.isClosed());
+    }
+
+    @Test
+    void givenConnectionObject_whenCreated_thenIsValid()
+            throws Exception
+    {
+        Connection connection = ConnectionValidation.getConnection();
+        assertTrue(connection.isValid(0));
+    }
+
+    @Test
+    void givenConnectionObject_whenValidated_thenIsValid()
+            throws Exception
+    {
+        Connection connection = ConnectionValidation.getConnection();
+        assertTrue(ConnectionValidation.isConnectionValid(connection));
+    }
+
+}