java学习笔记--JDBC实例

使用的数据库：

mysql> use xiao;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
+----------------+
| Tables_in_xiao |
+----------------+
| students       |
+----------------+
1 row in set (0.00 sec)

mysql> desc students;
+-------+---------------------+------+-----+---------+----------------+
| Field | Type                | Null | Key | Default | Extra          |
+-------+---------------------+------+-----+---------+----------------+
| id    | int(10) unsigned    | NO   | PRI | NULL    | auto_increment |
| name  | char(8)             | NO   |     | NULL    |                |
| sex   | char(4)             | NO   |     | NULL    |                |
| age   | tinyint(3) unsigned | NO   |     | NULL    |                |
| tel   | char(13)            | YES  |     | -       |                |
+-------+---------------------+------+-----+---------+----------------+
5 rows in set (0.04 sec)

mysql> select * from students;
+----+---------+-----+-----+-------------+
| id | name    | sex | age | tel         |
+----+---------+-----+-----+-------------+
|  1 | xiaoye  | m   |  31 | 15712340618 |
|  2 | heilong | m   |  31 | 13312342130 |
|  3 | baba    | m   |  60 | 13312348223 |
|  4 | xiaoye  | m   |  30 | 17712341103 |
+----+---------+-----+-----+-------------+
4 rows in set (0.00 sec)

mysql>

java例子：

import com.mysql.jdbc.Driver;

import java.sql.*;

public class JDBCTest {
    public static void main(String[] args) {
        Connection connection = new JDBCTest().getConnection(); //调用getConnection方法
        try {
            Statement statement = connection.createStatement();
            ResultSet resultSet = statement.executeQuery("select * from students;"); //executeQuery executeUpdate execute 的区别
            while(resultSet.next()) {　　//循环resultSet，调用next（）移动至第一条数据，没有hasnext（）方法；
                int id = resultSet.getInt(1);
                String name = resultSet.getString(2);
                String sex = resultSet.getString(3);
                int age = resultSet.getInt(4);
                String tel = resultSet.getString(5);
                System.out.println(id + " " + name + " " + sex + " " + age + " " + tel + ";");
            }

        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

    }

    public Connection getConnection() {
        try {
            Class.forName("com.mysql.jdbc.Driver");　　//加载驱动
            return DriverManager.getConnection("jdbc:mysql://localhost:3306/xiao","root","×××××××"); //链接数据库 注意ruturn
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;　　//return
    }
}