JDBC01

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基础操作

import com.mysql.jdbc.Driver;

import java.sql.*;
import java.util.Date;
import java.util.Properties;

public class JDBCTest01 {
    public static void main(String[] args) {
        Connection con = null;
        Statement st = null;
        ResultSet rs = null;
        try {
            //1.注册驱动,使用mysql驱动(注册驱动,创建连接)
            //DriverManager.registerDriver(new Driver());不建议使用,原因:注册两次驱动
            Class.forName("com.mysql.jdbc.Driver");

            //2.创建连接
            //方法一:
            /*String url = "jdbc:mysql://localhost:3306/mydb1";
            String user = "root";
            String password = "123456";
            Connection con = DriverManager.getConnection(url, user, password);*/
            //方法二:
            /*String url = "jdbc:mysql://localhost:3306/mydb1?user=root&password=123456";
            Connection con = DriverManager.getConnection(url);*/
            //方法三:
            String url = "jdbc:mysql://localhost:3306/mydb1";
            Properties pro = new Properties();
            pro.put("user", "root");
            pro.put("password", "123456");
            //路径简写:默认本机mysql
            //String url = "jdbc:mysql:///mydb1";

            con = DriverManager.getConnection(url, pro);
            //3.得到执行sql语句的Statement对象
            st = con.createStatement();

            //4.执行sql语句，并返回结果
            rs = st.executeQuery("select * from user ;");

            //5.处理结果
            while (rs.next()) {
            /*//根据列的索引获取每一列的数据
            System.out.print(rs.getObject(1));
            System.out.print(rs.getObject(2));
            System.out.print(rs.getObject(3));
            System.out.print(rs.getObject(4));
            System.out.print(rs.getObject(5));
            System.out.println();*/
                //根据列明来获取每一列的数据
           /* System.out.print(rs.getObject("id"));
            System.out.print(rs.getObject("name"));
            System.out.print(rs.getObject("password"));
            System.out.print(rs.getObject("email"));
            System.out.print(rs.getObject("birthday"));
            System.out.println();*/
                //getObject将数据类型转换为Object类型,通过对应的方法可以获取相应类型的数据
                System.out.print(rs.getInt("id"));//mysql:int -> java:int
                System.out.print(rs.getString("name"));//mysql:varchar -> java:String
                System.out.print(rs.getString("password"));//mysql:varchar -> java:String
                System.out.print(rs.getString("email"));//mysql:varchar -> java:String
                System.out.print(rs.getDate("birthday"));
                //getDate方法属于java.sql.Date(继承自java.util.Date)
                System.out.println();
            }
            /*boolean next()  将光标从当前位置向前移一行
            boolean previous() 将光标移动到此 ResultSet 对象的上一行
            boolean absolute(int row) 参数是当前行的索引,从1开始 根据行的索引定位移动的指定索引行
            void afterLast()  将光标移动到末尾,正好位于最后一行之后
            void beforeFirst()  将光标移动到开头,正好位于第一行之前*/
        } catch (Exception e) {

        } finally {
            //6.关闭资源
            if (rs != null) {
                try {
                    rs.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (st != null) {
                try {
                    st.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }

        }
    }
}