Java连接Oracle数据库并查询

 public class DbConn { private static String driver = "oracle.jdbc.driver.OracleDriver"; private static String url = "jdbc:oracle:thin:@localhost:1521:orcl"; private static String user = "root"; private static String password = "root"; private static Connection conn = null; static { try { Class.forName(driver); Log.logD("------加载驱动成功-----"); conn = (Connection) DriverManager.getConnection(url, user, password); Log.logD("------连接成功-----"); } catch (ClassNotFoundException e) { Log.logD("------加载驱动失败，驱动类未找到------"); e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); Log.logD("------加载驱动失败------"); } } public static Connection getConn(){ return conn; } }

 public class DbGetCan { private static PreparedStatement pstmt; private static ResultSet rs; private static Connection conn; public static String select(String sql) { conn=DbConn.getConn(); try { pstmt = conn.prepareStatement(sql); rs = pstmt.executeQuery(); return getJsonArray(); } catch (SQLException e) { e.printStackTrace(); } catch (JSONException e) { // TODO Auto-generated catch block e.printStackTrace(); } return null; } /* * 将查询结果转化为json数组 需要导入Json jar包 */ public static String getJsonArray() throws SQLException, JSONException { JSONArray jsonArray=new JSONArray(); ResultSetMetaData metaData = (ResultSetMetaData) rs.getMetaData(); int columnCount = metaData.getColumnCount(); while (rs.next()) { JSONObject jsonData = new JSONObject(); for (int i = 1; i <= columnCount; i++) { String columnName = metaData.getColumnLabel(i); String value = rs.getString(columnName); jsonData.put(columnName, value); } jsonArray.put(jsonData); } rs.close(); pstmt.close(); return jsonArray.toString(); } }

 //调用 String sql="select * from table"; String result=DbGetGps.select(sql); System.out.println(result);