创建DAO模式的步骤

1.建立数据库epet 2.创建实体类，和相对应的数据库是对应的 3.创建Dao的基类接口类BaseDao 4.创建Dao的实现类BaseDaoImpl 5.创建具体表的Dao类

6.创建具体表的Dao实现类 7.创建业务逻辑层级的接口类PetService 8.创建业务逻辑层的接口实现类：PetServiceImpl  9.创建测试类

下面写一个登录的操作用DAO模式：

1.创建实体类：人的实体类

 package com.beiwo.epet.entity;
 
 import java.io.Serializable;
 
 public class Master implements Serializable{
 
     private static final long serialVersionUID = -975099318646595542L;
 
     private int id;
     private String loginId;
     private String password;
     public int getId() {
         return id;
     }
     public void setId(int id) {
         this.id = id;
     }
     public String getLoginId() {
         return loginId;
     }
     public void setLoginId(String loginId) {
         this.loginId = loginId;
     }
     public String getPassword() {
         return password;
     }
     public void setPassword(String password) {
         this.password = password;
     }
     public static long getSerialversionuid() {
         return serialVersionUID;
     }
 
 }

2.接口类的基类：

 package com.beiwo.epet.entity;
 
 import java.io.Serializable;
 
 public class Master implements Serializable{
 
     private static final long serialVersionUID = -975099318646595542L;
 
     private int id;
     private String loginId;
     private String password;
     public int getId() {
         return id;
     }
     public void setId(int id) {
         this.id = id;
     }
     public String getLoginId() {
         return loginId;
     }
     public void setLoginId(String loginId) {
         this.loginId = loginId;
     }
     public String getPassword() {
         return password;
     }
     public void setPassword(String password) {
         this.password = password;
     }
     public static long getSerialversionuid() {
         return serialVersionUID;
     }
 
 }
 
 package com.beiwo.epet.dao;
 
 import com.beiwo.epet.entity.Master;
 
 public interface MasterDao extends BaseDao{
 
     /**
      *
      * @param loginId 用户名
      * @param password 密码
      * @return Master
      */
     public Master findMasterByLoginIdAndPassword(String loginId,String password);
 
 }

3.接口类的基类的实现类

 package com.beiwo.epet.dao;
 
 import com.beiwo.epet.entity.Master;
 
 public interface MasterDao extends BaseDao{
 
     /**
      *
      * @param loginId 用户名
      * @param password 密码
      * @return Master
      */
     public Master findMasterByLoginIdAndPassword(String loginId,String password);
 
 }
 
 package com.beiwo.epet.dao;
 
 import com.beiwo.epet.entity.Master;
 
 public interface MasterDao extends BaseDao{
 
     /**
      *
      * @param loginId 用户名
      * @param password 密码
      * @return Master
      */
     public Master findMasterByLoginIdAndPassword(String loginId,String password);
 
 }

4.创建业务逻辑层级的接口类PetService

 package com.beiwo.epet.service;
 
 import com.beiwo.epet.entity.Master;
 
 public interface MasterService {
 
     public Master login(String loginId,String password);
 
 }

5.创建业务逻辑层的接口实现类

 package com.beiwo.epet.service.impl;
 
 import com.beiwo.epet.dao.MasterDao;
 import com.beiwo.epet.dao.impl.MasterDaoImpl;
 import com.beiwo.epet.entity.Master;
 import com.beiwo.epet.service.MasterService;
 
 public class MasterServiceImpl implements MasterService{
 
     @Override
     public Master login(String loginId, String password) {
         MasterDao masterDao=new MasterDaoImpl();
         return masterDao.findMasterByLoginIdAndPassword(loginId, password);
     }
 
 }

6.测试类：

 package com.beiwo.epet.test;
 
 import java.util.Scanner;
 
 import org.junit.Test;
 
 import com.beiwo.epet.entity.Master;
 import com.beiwo.epet.service.MasterService;
 import com.beiwo.epet.service.impl.MasterServiceImpl;
 
 public class TestMasterDao {
 
     @Test
     public void testLogin(){
         MasterService masterService=new MasterServiceImpl();
 
         Scanner input=new Scanner(System.in);
 
         System.out.println("请输入用户名:");
         String loginId=input.nextLine().trim();//去掉两端的空格
 
         System.out.println("请输入密码:");
         String password=input.nextLine().trim();
 
         Master master=masterService.login(loginId, password);
 
         if(null!=master){
             System.out.println("登陆成功");
         }else{
             System.out.println("登陆失败");
         }
 
     }
 
 }