Merge pull request #16879 from Michaelin007/blob

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

Author: Maiklins

persistence-modules/core-java-persistence-3/retrieve-warehouse.png

@@ -0,0 +1,104 @@
+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/main/java/storefileblob/JdbcConnection.java

@@ -0,0 +1,54 @@
+package storefileblob;
+
+import org.junit.Test;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import java.io.IOException;
+import java.sql.SQLException;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class JdbcConnectionUnitTest {
+
+    private static final String TEST_FILE_PATH = "warehouse.png";
+    private static final String RETRIEVED_FILE_PATH = "retrieve-warehouse.png";
+    private static JdbcConnection jdbcConnection;
+    String selectBlob = """
+        SELECT picture FROM warehouses WHERE id=?
+        """;
+
+    @BeforeAll
+    public static void setUp() throws SQLException {
+        jdbcConnection = new JdbcConnection();
+        jdbcConnection.createSchema();
+    }
+
+    @Test
+    public void givenDatabaseSchema_whenJdbcConnectionIsEstablished_thenCreateSchema() throws SQLException {
+        assertTrue(jdbcConnection.createSchema());
+    }
+
+    @ParameterizedTest
+    @CsvSource({ "1, 'Liu', 3000", "2, 'Walmart', 5000" })
+    public void givenBlobFile_whenInsertingTheBlobFileAsByteArray_thenSuccessful(int id, String name, int capacity) throws SQLException, IOException {
+        boolean result = jdbcConnection.insertFile(id, name, capacity, TEST_FILE_PATH);
+        assertTrue(result);
+    }
+
+    @ParameterizedTest
+    @CsvSource({ "7, 'Dylan', 8000", "8, 'Jumia', 1000" })
+    public void givenBlobFile_whenInsertingTheFileIntoTheDatabaseInChunks_thenSuccessful(int id, String name, int capacity) throws SQLException, IOException {
+        boolean result = jdbcConnection.insertFileAsStream(id, name, capacity, TEST_FILE_PATH);
+        assertTrue(result);
+    }
+
+    @Test
+    public void givenAnEntityWithBlob_whenReadingBlobAndConvertingItToFile_thenSuccessful() throws SQLException, IOException {
+        boolean result = JdbcConnection.writeBlobToFile(selectBlob, 1, 2, RETRIEVED_FILE_PATH);
+        byte[] expectedBytes = JdbcConnection.convertFileToByteArray(TEST_FILE_PATH);
+        byte[] retrievedBytes = JdbcConnection.convertFileToByteArray(RETRIEVED_FILE_PATH);
+        assertArrayEquals(expectedBytes, retrievedBytes);
+    }
+
+}