jdbc连接数据库及与数据库的交互

package com.unis.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

import com.unis.vo.UserVo;



public class UserDao {
    public void insertUser (UserVo uv){
        Connection con = null;
        Statement st = null;
        
        try {
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/userm","root","");
            st = con.createStatement();
            String sql="sql语句";
            int tempFlag = st.executeUpdate(sql);
            System.out.println(tempFlag);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        finally{
            try {
                st.close();
                con.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
        }
    }
}

有点看不懂，能不能详细解释一下这些语句，尤其是connection和statement，含有try catc，俺菜菜