https://jira.baeldung.com/browse/BAEL-7958

Author: Michaelin007

persistence-modules/core-java-persistence-3/src/main/java/storefileblob/JdbcConnection.java

@@ -0,0 +1,105 @@
+package storefileblob;
+
+import java.io.IOException;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.ByteArrayOutputStream;
+import java.sql.ResultSet;
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.Statement;
+import java.sql.SQLException;
+import java.io.FileOutputStream;
+import java.io.InputStream;
+
+public class JdbcConnection {
+
+    public static Connection connect() throws SQLException {
+        Connection connection = DriverManager.getConnection("jdbc:h2:./test", "sa", "");
+        return connection;
+
+    }
+
+    public static byte[] convertFileToByteArray(String filePath) throws IOException {
+        File file = new File(filePath);
+        try (FileInputStream fileInputStream = new FileInputStream(file); ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream()) {
+            byte[] buffer = new byte[1024];
+            for (int len; (len = fileInputStream.read(buffer)) != -1; ) {
+                byteArrayOutputStream.write(buffer, 0, len);
+            }
+            return byteArrayOutputStream.toByteArray();
+        }
+    }
+
+    public static boolean writeBlobToFile(String query, int paramIndex, int id, String filePath) throws IOException, SQLException {
+        try (Connection connection = connect(); PreparedStatement statement = connection.prepareStatement(query)) {
+            statement.setInt(paramIndex, id);
+            try (ResultSet resultSet = statement.executeQuery(); FileOutputStream fileOutputStream = new FileOutputStream(new File(filePath))) {
+                while (resultSet.next()) {
+                    InputStream input = resultSet.getBinaryStream("picture");
+                    byte[] buffer = new byte[1024];
+                    int bytesRead;
+                    while ((bytesRead = input.read(buffer)) > 0) {
+                        fileOutputStream.write(buffer, 0, bytesRead);
+                    }
+                }
+                return true;
+            }
+        }
+    }
+
+    public boolean createSchema() throws SQLException {
+        String sql = """
+            CREATE TABLE IF NOT EXISTS warehouses (
+            id INTEGER PRIMARY KEY,
+            name text NOT NULL,
+            capacity REAL,
+            picture BLOB
+            );""";
+        try (Connection connection = connect(); Statement stmt = connection.createStatement()) {
+            stmt.execute(sql);
+            return true;
+        }
+    }
+
+    public boolean insertFile(int id, String name, int capacity, String picture) throws SQLException, IOException {
+        String insertSql = """
+            INSERT INTO warehouses(id,name,capacity,picture) VALUES(?,?,?,?)
+            """;
+        try (Connection conn = connect()) {
+            if (conn != null) {
+                PreparedStatement stmt = conn.prepareStatement(insertSql);
+                stmt.setInt(1, id);
+                stmt.setString(2, name);
+                stmt.setDouble(3, capacity);
+                stmt.setBytes(4, convertFileToByteArray(picture));
+                stmt.executeUpdate();
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public boolean insertFileAsStream(int id, String name, int capacity, String filePath) throws SQLException, IOException {
+        String insertSql = """
+            INSERT INTO warehouses(id,name,capacity,picture) VALUES(?,?,?,?)
+            """;
+        try (Connection conn = connect()) {
+            if (conn != null) {
+                PreparedStatement stmt = conn.prepareStatement(insertSql);
+                stmt.setInt(1, id);
+                stmt.setString(2, name);
+                stmt.setDouble(3, capacity);
+                File file = new File(filePath);
+                try (FileInputStream fis = new FileInputStream(file)) {
+                    stmt.setBinaryStream(4, fis, file.length());
+                    stmt.executeUpdate();
+                    return true;
+                }
+
+            }
+        }
+        return false;
+    }
+}

persistence-modules/core-java-persistence-3/src/test/java/storefileblob/JdbcConnectionUnitTest.java

@@ -0,0 +1,50 @@
+package storefileblob;
+
+import org.junit.Test;
+import org.junit.jupiter.api.MethodOrderer;
+import org.junit.jupiter.api.Order;
+import org.junit.jupiter.api.TestMethodOrder;
+
+import java.io.IOException;
+import java.sql.SQLException;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+@TestMethodOrder(MethodOrderer.OrderAnnotation.class)
+public class JdbcConnectionUnitTest {
+
+    String selectBlob = """
+        SELECT picture FROM warehouses WHERE id=?
+        """;
+
+    @Test
+    @Order(1)
+    public void givenDatabaseSchema_whenJdbcConnectionIsEstablished_thenCreateSchema() throws SQLException {
+        JdbcConnection jdbcConnection = new JdbcConnection();
+        assertTrue(jdbcConnection.createSchema());
+    }
+
+    @Test
+    @Order(3)
+    public void givenBlobFile_whenInsertingTheBlobFileIntoTheWarehouseTable_thenSuccessful() throws SQLException, IOException {
+        JdbcConnection jdbcConnection = new JdbcConnection();
+        jdbcConnection.createSchema();
+        assertTrue(jdbcConnection.insertFile(4, "Liu", 3000, "warehouse.png"));
+    }
+
+    @Test
+    @Order(2)
+    public void givenBlobFile_whenInsertingTheFileIntoTheDatabaseAsStream_thenSuccessful() throws SQLException, IOException {
+        JdbcConnection jdbcConnection = new JdbcConnection();
+        jdbcConnection.createSchema();
+        assertTrue(jdbcConnection.insertFileAsStream(6, "Liu", 3000, "warehouse.png"));
+    }
+
+    @Test
+    @Order(4)
+    public void givenAnEntityWithBlob_whenReadingBlobAndConvertingItToFile_thenSuccessful() throws SQLException, IOException {
+        JdbcConnection jdbcConnection = new JdbcConnection();
+        assertTrue(JdbcConnection.writeBlobToFile(selectBlob, 1, 6, "retrieve-warehouse.png"));
+    }
+
+}