JDBC的学习（一）——Java与MySQL的连接

package cn.yn.text0;

import java.sql.*;

public class TextJdbc1{
    //JDBC驱动名以及数据库URL
    static final String JDBC_DRIVER = "com.mysql.cj.jdbc.Driver";
    static final String DB_URL = "jdbc:mysql://localhost:3306/textjdbc?serverTimezone=GMT";
    //数据库的用户名以及密码
    static final String USER = "root";
    static final String PWD = "123";
    public static void main(String[] args) {
        Connection connection = null;
        Statement statement = null;
        ResultSet rs = null;
        try {
            //1、加载驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2、打开链接
            System.out.println("正在连接到数据库。。。");
            connection = DriverManager.getConnection(DB_URL, USER, PWD);
            //3、查询
            statement = connection.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
            rs = statement.executeQuery("select * from tb_user");
            
            //循环取出
            while(rs.next()) {
                System.out.println("编号"+rs.getInt(1)+"姓名"+rs.getString(2));
            }
            //如果我还是想重新使用游标
            rs.absolute(2);
            System.out.println("*****************************");
            while(rs.next()) {
                System.out.println("编号"+rs.getInt(1)+"姓名"+rs.getString(2));
            }
            
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            //处理jdbc错误
            e.printStackTrace();
        }finally {
            //关闭资源
            if(statement != null) {
                try {
                    statement.close();
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                statement = null;//垃圾回收
            }
            if(connection  != null) {
                try {
                    connection.close();
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                connection = null;
            }
            if(rs != null) {
                try {
                    rs.close();
                } catch (Exception e2) {
                    // TODO: handle exception
                }
            }
        }
    }
}

其中使用MySQL-connector-Java-8.0 的jar包时，JDBC_DRIVER为"com.mysql.cj.jdbc.Driver"，DB_URL为 "jdbc:mysql://localhost:3306/textjdbc?serverTimezone=GMT"。