使用Java JDBC和PostgreSQL编写和读取pdf文件

Question

我在PostgreSQL表上有一个包含bytea数据类型的表。

我正在尝试使用JDBC结果集从bytea数据中编写和检索pdf文件。

但是，在检索文件后尝试显示文件时文件已损坏。

这是我的代码：

private void insertBytea(java.io.File file) {
    try {
        Class.forName("org.postgresql.Driver");
    } catch (ClassNotFoundException ex) {
        ex.printStackTrace();
        Logger.getLogger(BeteaTest.class.getName()).log(Level.SEVERE, null, ex);
    }

    try {
        java.sql.Connection connectDB = java.sql.DriverManager.getConnection("jdbc:postgresql://localhost:5433/funsoft", "postgres", "xxx");

        connectDB.setAutoCommit(false);

        java.sql.PreparedStatement pstmt = connectDB.prepareStatement("INSERT INTO test_binary (test_bytea) VALUES(?)");
        java.io.FileInputStream fis;
        try {
            fis = new java.io.FileInputStream(file);
            pstmt.setBinaryStream(1, fis, (int) file.length());

            pstmt.executeUpdate();
            connectDB.commit();
            pstmt.close();

            java.sql.PreparedStatement pstmtR = connectDB.prepareStatement("SELECT * FROM test_binary LIMIT 1");
            //  pstmtR.setString(1, file.getName());
            java.sql.ResultSet rs = pstmtR.executeQuery();
            while (rs.next()) {
                byte[] imgBytes = rs.getBytes(2);
                //java.io.InputStream ios = rs.getBinaryStream(2);
                java.io.ByteArrayInputStream byteaStream = new java.io.ByteArrayInputStream(imgBytes);
                java.io.File tempFile;
                try {
                    tempFile = java.io.File.createTempFile("REP" + com.afrisoftech.lib.DateLables.getDateLabel() + "_", ".pdf");
                    java.io.FileOutputStream fileIS = new java.io.FileOutputStream(tempFile);
                    fileIS.write(imgBytes);
                    fileIS.close();
                    // this is where i am trying to display the file
                    com.afrisoftech.lib.PDFRenderer.renderPDF(tempFile);
                } catch (IOException ex) {
                    Logger.getLogger(BeteaTest.class.getName()).log(Level.SEVERE, null, ex);
                }

            }
            try {
                fis.close();
            } catch (IOException ex) {
                ex.printStackTrace();
                Logger.getLogger(BeteaTest.class.getName()).log(Level.SEVERE, null, ex);
            }
        } catch (FileNotFoundException ex) {
            Logger.getLogger(BeteaTest.class.getName()).log(Level.SEVERE, null, ex);
        }

    } catch (SQLException ex) {
        ex.printStackTrace();
        Logger.getLogger(BeteaTest.class.getName()).log(Level.SEVERE, null, ex);
    }
}