第八章项目这部分听不懂怎么办？
package util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class DBHelper{
private static final String driver = "com.mysql.jdbc.Driver";//数据库驱动
//连接数据库的URL地址
private static final String url = "jdbc:mysql://localhost:3306/shopping?useUnicode=true"
+ "&characterEncoding=UTF-8";
private static final String username = "root";//数据库的用户名
private static final String password = "123456";//数据库的密码
private static Connection conn;
//静态代码块负责加载驱动
static
{
try
{
Class.forName(driver);
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
//单例模式返回数据库连接对象
public static Connection getConnection() throws Exception
{
if(conn==null)
{
conn = DriverManager.getConnection(url, username, password);
}
return conn;
}
public static void main(String[] args) {
try
{
Connection conn = DBHelper.getConnection();
if(conn!=null)
{
System.out.println("数据库连接正常！");
}
else
{
System.out.println("数据库连接异常！");
}
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
}
