元数据 MetaData和可滚动的结果集

元数据 Meta Data/* * 元数据 Meta Data */public class Test03 {Connection conn = null;PreparedStatement pstmt=null;ResultSet rs = null;(){conn=DBUtil.getConnection();try {DatabaseMetaData dbmd=conn.getMetaData();//获取数据库元数据System.out.println(dbmd.getDatabaseProductName());System.out.println(dbmd.getDatabaseProductVersion());System.out.println(dbmd.getDriverName());System.out.println(dbmd.getDriverVersion());pstmt=conn.prepareStatement(“select username,password from user”);rs=pstmt.executeQuery();//获取结果集元数据ResultSetMetaData rsmd=rs.getMetaData();System.out.println(rsmd.getColumnCount());System.out.println(rsmd.getColumnName(1));System.out.println(rsmd.getColumnName(2));} catch (SQLException e) {e.printStackTrace();}}(String[] args) {new Test03().test();}}可滚动的结果集/* * 可滚动的结果集 */public class Test04 {Connection conn = null;PreparedStatement pstmt = null;ResultSet rs = null;// 读取到指定用户时插入一条记录public void test01() {String sql = “select * from user”;try {conn = DBUtil.getConnection();pstmt = conn.prepareStatement(sql,ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);rs = pstmt.executeQuery(); // 可滚动结果集，可以更新表while (rs.next()) {String name = rs.getString(“username”);if (name.equals(“tom”)) {// 判断当前读取的用户// 将光标移动到插入行，插入行实际上就是一个缓冲区，用来准备数据rs.moveToInsertRow();rs.updateString(“username”, “alex”);rs.updateString(“password”, “999”);// 提交缓冲区中的数据rs.insertRow();System.out.println(“插入用户成功！”);// 将光标移动到当前行，即插入记录前的那条记录rs.moveToCurrentRow();}System.out.println(rs.getInt(1) + “,” + rs.getString(2) + “,”+ rs.getString(3));}} catch (SQLException e) {e.printStackTrace();} finally {DBUtil.closeAll(rs, pstmt, conn);}}// 删除指定用户public void test02() {String sql = “select * from user”;try {conn = DBUtil.getConnection();pstmt = conn.prepareStatement(sql,ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);rs = pstmt.executeQuery();while (rs.next()) {String name = rs.getString(“username”);if (name.equals(“bbb”)) {rs.deleteRow();// 删除当前行//rs.next();// 删除后将光标下移System.out.println(“删除用户成功”);}System.out.println(rs.getInt(1) + “,” + rs.getString(2) + “,”+ rs.getString(3));}} catch (SQLException e) {e.printStackTrace();} finally {DBUtil.closeAll(rs, pstmt, conn);}}//移动游标public void test03() {String sql = “select * from user”;try {conn = DBUtil.getConnection();pstmt = conn.prepareStatement(sql,ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);rs = pstmt.executeQuery();while (rs.next()) {String name = rs.getString(“username”);if (name.equals(“s001”)) {rs.relative(3);}System.out.println(rs.getInt(1) + “,” + rs.getString(2) + “,”+ rs.getString(3));}} catch (SQLException e) {e.printStackTrace();} finally {DBUtil.closeAll(rs, pstmt, conn);}}public static void main(String[] args) {new Test04().test03();}}

，找寻隐藏在山间的纯净和那“鸟鸣山更幽”的飞鸟。