CustomerDao接口：

package cn.csdn.customer.dao;

import cn.csdn.customer.domain.Customer;

public interface CustomerDao extends Dao<Customer,Integer> {
  int getCount();
}

CustomerDaoImpl接口实例类：

package cn.csdn.customer.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import cn.csdn.customer.domain.Customer;
import cn.csdn.customer.util.JdbcUtil;

public class CustomerDaoImpl implements CustomerDao {
 
 /* 封装数据库操作的对象 */
 private Connection conn;
 private PreparedStatement pstmt;
 private ResultSet rs;
 
 public boolean insert(Customer entity) {
  /* 第一步：声明返回值变量 */
  boolean flag = false;
  try {
   /* 第二步：获取连接对象 */
   conn = JdbcUtil.getConn();
   /* 第三步：定义sql语句 */
   String sql = "insert into customer(name,gender,birthday,cellphone,Email,preference,type,Description)values(?,?,?,?,?,?,?,?)";
   /* 第四步：根据sql语句获取预处理对象 */
   pstmt = conn.prepareStatement(sql);
   /* 第五步：为占位符赋值 */
   int index = 1;
   pstmt.setObject(index++, entity.getName());
   pstmt.setObject(index++, entity.getGender());
   pstmt.setObject(index++, entity.getBirthday());
   pstmt.setObject(index++, entity.getCellphone());