java数据库开发之JDBC的完整封装兼容多种数据库

 import java.sql.CallableStatement; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.SQLException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; /** * 对jdbc的完整封装 * */ public class JDBCUtil { private static String driver = null; private static String url = null; private static String username = null; private static String password = null; private CallableStatement callableStatement = null;//创建CallableStatement对象 private Connection conn = null; private PreparedStatement pst = null; private ResultSet rst = null; /*	static { try { // 加载数据库驱动程序 Class.forName(driver); } catch (ClassNotFoundException e) { System.out.println("加载驱动错误"); System.out.println(e.getMessage()); } } */ public JDBCUtil(String driver,String url ,String username,String password) { this.driver = driver; this.url = url; this.username = username; this.password = password; } /** * 建立数据库连接 * @return 数据库连接 */ public Connection getConnection() { try { // 加载数据库驱动程序 try { Class.forName(driver); } catch (ClassNotFoundException e) { System.out.println("加载驱动错误"); System.out.println(e.getMessage()); e.printStackTrace(); } // 获取连接 conn = DriverManager.getConnection(url, username, password); } catch (SQLException e) { System.out.println(e.getMessage()); } return conn; } /** * insert update delete SQL语句的执行的统一方法 * @param sql SQL语句 * @param params 参数数组，若没有参数则为null * @return 受影响的行数 */ public int executeUpdate(String sql, Object[] params) { // 受影响的行数 int affectedLine = 0; try { // 获得连接 conn = this.getConnection(); // 调用SQL pst = conn.prepareStatement(sql); // 参数赋值 if (params != null) { for (int i = 0; i  excuteQuery(String sql, Object[] params) { // 执行SQL获得结果集 ResultSet rs = executeQueryRS(sql, params); // 创建ResultSetMetaData对象 ResultSetMetaData rsmd = null; // 结果集列数 int columnCount = 0; try { rsmd = rs.getMetaData(); // 获得结果集列数 columnCount = rsmd.getColumnCount(); } catch (SQLException e1) { System.out.println(e1.getMessage()); } // 创建List List