jdbc连接

标准八部曲

import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;public class Jdbc {public static void main(String[] args) {Connection connection = null;PreparedStatement preparedStatement = null;ResultSet resultSet = null;try {//1、加载数据库驱动Class.forName("com.mysql.jdbc.Driver");//2、通过驱动管理类获取数据库链接connection =  DriverManager.getConnection("jdbc:mysql://localhost:3306/zn", "root", "123456");//3、定义sql语句 ?表示占位符String sql = "select * from book";//4、获取预处理statementpreparedStatement = connection.prepareStatement(sql);//5、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");//6、向数据库发出sql执行查询，查询出结果集resultSet =  preparedStatement.executeQuery();//7、遍历查询结果集while(resultSet.next()){System.out.println(resultSet.getString("name"));}} catch (Exception e) {e.printStackTrace();}finally{//8、释放资源if(resultSet!=null){try {resultSet.close();} catch (SQLException e) {e.printStackTrace();}}if(preparedStatement!=null){try {preparedStatement.close();} catch (SQLException e) {e.printStackTrace();}}if(connection!=null){try {connection.close();} catch (SQLException e) {e.printStackTrace();}}}}}