1-jdbc程序

    xiaoxiao2021-03-25  161

    mysql 数据库驱动包 mysql-connector-java-x.x.x-bin.jar

    pom文件 <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.38</version> </dependency> //数据库连接 Connection connection = null; //预编译的Statement,使用预编译的Statement提高数据库性能 PreparedStatement preparedStatement = null; //结果 集 ResultSet resultSet = null; try { //加载数据库驱动 Class.forName("com.mysql.jdbc.Driver"); //通过驱动管理类获取数据库链接 connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/xiatest?characterEncoding=utf-8", "root", "root"); //定义sql语句 ?表示占位符 String sql = "select * from user where username = ?"; //获取预处理statement preparedStatement = connection.prepareStatement(sql); //设置参数,第一个参数为sql语句中参数的序号(从1开始),第二个参数为设置的参数值 preparedStatement.setString(1, "王五"); //向数据库发出sql执行查询,查询出结果集 resultSet = preparedStatement.executeQuery(); //遍历查询结果集 while(resultSet.next()){ System.out.println(resultSet.getString("id")+" "+resultSet.getString("username")); } } catch (Exception e) { e.printStackTrace(); }finally{ //释放资源 if(resultSet!=null){ try { resultSet.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } if(preparedStatement!=null){ try { preparedStatement.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } if(connection!=null){ try { connection.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }
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