Java实现从Oracle数据库读取BLOB字段的内容,并将其转换为证书文件。
一、实现步骤
- 从Oracle数据库读取BLOB字段的内容:使用
ResultSet
读取BLOB字段的数据。 - 将BLOB内容转换为字节数组:将读取的BLOB数据转换为字节数组。
- 将字节数组保存为证书文件:将字节数组转换为字符串并添加头尾标识,然后将其保存为证书文件。
二、实现代码
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;public class BlobToCertificateExample {public static void main(String[] args) {String dbUrl = "jdbc:oracle:thin:@localhost:1521:test"; // 数据库URLString dbUser = "username"; // 数据库用户名String dbPassword = "password"; // 数据库密码String certFilePath = "path/save/certificate.crt"; // 要保存的证书文件路径Connection conn = null;PreparedStatement pstmt = null;ResultSet rs = null;try {// 连接数据库conn = DriverManager.getConnection(dbUrl, dbUser, dbPassword);// 查询BLOB字段String sql = "SELECT blob_column FROM my_table WHERE id = ?";pstmt = conn.prepareStatement(sql);pstmt.setInt(1, 10); //ID 为 10rs = pstmt.executeQuery();if (rs.next()) {// 获取BLOB数据byte[] certBytes = rs.getBytes("blob_column");// 将字节数组转换为字符串,并添加证书的头尾String certContent = convertToCertificate(certBytes);// 将证书内容写入文件saveToFile(certFilePath, certContent);System.out.println("Certificate saved successfully.");}} catch (Exception e) {e.printStackTrace();} finally {try {if (rs != null) rs.close();if (pstmt != null) pstmt.close();if (conn != null) conn.close();} catch (Exception e) {e.printStackTrace();}}}// 将字节数组转换为证书内容,并添加头尾标识private static String convertToCertificate(byte[] certBytes) {String certContent = new String(certBytes);// 添加头尾标识StringBuilder sb = new StringBuilder();sb.append("-----BEGIN CERTIFICATE-----\n");sb.append(certContent);sb.append("\n-----END CERTIFICATE-----");return sb.toString();}// 将证书内容保存为文件private static void saveToFile(String filePath, String content) throws Exception {try (OutputStream os = new FileOutputStream(filePath)) {os.write(content.getBytes());}}
}