数据访问对象模式
数据访问对象模式
实际案例
类信息概览：
| 类名 | 说明 |
|---|---|
| Main.java | 方法的总入口 |
| UserDao.java | 用户 dao 接口 |
| User.java | 用户 |
| UserDaoImpl.java | 用户 dao 实现 |
定义
- UserDao.java
[java]
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30/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
* Copyright (c) 2012-2018. houbinbini Inc.
* design-pattern All rights reserved.
*/
package com.ryo.design.pattern.note.dao;
import java.util.List;
/**
* <p> </p>
*
* <pre> Created: 2018/5/28 下午6:55 </pre>
* <pre> Project: design-pattern </pre>
*
* @author houbinbin
* @version 1.0
* @since JDK 1.7
*/
public interface UserDao {
/**
* 查询所有的用户信息
* @return 用户列表
*/
List<User> queryUsers();
}
- User.java
[java]
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31/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
* Copyright (c) 2012-2018. houbinbini Inc.
* design-pattern All rights reserved.
*/
package com.ryo.design.pattern.note.dao;
import lombok.Builder;
import lombok.Data;
/**
* <p> </p>
*
* <pre> Created: 2018/5/28 下午6:55 </pre>
* <pre> Project: design-pattern </pre>
*
* @author houbinbin
* @version 1.0
* @since JDK 1.7
*/
@Data
@Builder
public class User {
private String name;
private int age;
}
- UserDaoImpl.java
[java]
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32/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
* Copyright (c) 2012-2018. houbinbini Inc.
* design-pattern All rights reserved.
*/
package com.ryo.design.pattern.note.dao;
import java.util.Arrays;
import java.util.List;
/**
* <p> </p>
*
* <pre> Created: 2018/5/28 下午6:55 </pre>
* <pre> Project: design-pattern </pre>
*
* @author houbinbin
* @version 1.0
* @since JDK 1.7
*/
public class UserDaoImpl implements UserDao {
@Override
public List<User> queryUsers() {
User user = User.builder().age(10).name("hello").build();
User user2 = User.builder().age(12).name("hello2").build();
return Arrays.asList(user, user2);
}
}
测试
- Main.java
[java]
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30/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
* Copyright (c) 2012-2018. houbinbini Inc.
* design-pattern All rights reserved.
*/
package com.ryo.design.pattern.note.dao;
import java.util.List;
/**
* <p> </p>
*
* <pre> Created: 2018/5/28 下午6:57 </pre>
* <pre> Project: design-pattern </pre>
*
* @author houbinbin
* @version 1.0
* @since JDK 1.7
*/
public class Main {
public static void main(String[] args) {
UserDao userDao = new UserDaoImpl();
List<User> userList = userDao.queryUsers();
System.out.println(userList);
}
}
- 测试结果
[plaintext]
1[User(name=hello, age=10), User(name=hello2, age=12)]
实现方式
UML & Code
UML
UML 图示如下
Code
代码地址
