JDBC——建立数据库连接

import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;

public class Test {
public static void main(String[] args) {

//声明Connection对象
Connection conn = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
//驱动程序名
String driver = "com.mysql.jdbc.Driver";
//用户名
String user = "root";
//密码
String password = "1234";
//url
String url = "jdbc:mysql://localhost:3306/db_person";

try {
String sql = "SELECT * FROM student";
//1.加载驱动
Class.forName(driver);
//2.获得connect连接
conn = (Connection) DriverManager.getConnection(url, user, password);
//3.获得PreparedStatement
preparedStatement = (PreparedStatement) conn.prepareStatement(sql);
//4.获得结果集
resultSet = preparedStatement.executeQuery();

while(resultSet.next()) {
int id = resultSet.getInt(1);
String name = resultSet.getString(2);
String sex = resultSet.getString(3);
int age = resultSet.getInt(4);

System.out.println(id +" "+ name + " " + sex + " " + age);
}

} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
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(conn != null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}
}
}