MyBatis(4)：使用limit实现分页

用limit实现分页，首先要创建一个Maven项目，搭建好mybatis的实验环境，并且连接好数据库

代码

1，编写dao接口

UserMapper

//查询全部用户实现分页
List<User> selectUser(Map<String,Integer> map);

2，编写对应Mapper映射文件的方法

startIndex：起始位置
startIndex=(currentPage-1)*pageSize
pageSize：页面大小
currentPage：当前页

<select id="selectUserByLimit" parameterType="Map" resultType="User">
    select * from user limit #{startIndex},#{pageSize}
</select>

3，测试

模拟分页数据：currentPage，pageSize

@Test
public void selectUser(){

<span class="hljs-comment">//创建sqlSession</span>
SqlSessionFactory sqlSessionFactory = MyBatisUtils.getSqlSessionFactory();
SqlSession sqlSession = sqlSessionFactory.openSession();

<span class="hljs-comment">//准备数据</span>
<span class="hljs-keyword">int</span> currentPage = <span class="hljs-number">1</span>;<span class="hljs-comment">//当前是第几页</span>
<span class="hljs-keyword">int</span> pageSize = <span class="hljs-number">2</span>; <span class="hljs-comment">//页面大小</span>

Map&lt;String, Integer&gt; <span class="hljs-built_in">map</span> = <span class="hljs-keyword">new</span> HashMap&lt;String, Integer&gt;();
<span class="hljs-built_in">map</span>.put(<span class="hljs-string">"startIndex"</span>,(currentPage<span class="hljs-number">-1</span>)*pageSize);
<span class="hljs-built_in">map</span>.put(<span class="hljs-string">"pageSize"</span>,pageSize);

<span class="hljs-comment">//测试</span>
UserDao mapper = sqlSession.getMapper(UserMapper.class);
List&lt;User&gt; users = mapper.selectUserByLimit(<span class="hljs-built_in">map</span>);

<span class="hljs-keyword">for</span> (User user : users) {
    System.out.println(user);
}

sqlSession.close();<span class="hljs-comment">//关闭连接</span>


<span class="hljs-comment">//创建sqlSession</span>
SqlSessionFactory sqlSessionFactory = MyBatisUtils.getSqlSessionFactory();
SqlSession sqlSession = sqlSessionFactory.openSession();

<span class="hljs-comment">//准备数据</span>
<span class="hljs-keyword">int</span> currentPage = <span class="hljs-number">1</span>;<span class="hljs-comment">//当前是第几页</span>
<span class="hljs-keyword">int</span> pageSize = <span class="hljs-number">2</span>; <span class="hljs-comment">//页面大小</span>

Map&lt;String, Integer&gt; <span class="hljs-built_in">map</span> = <span class="hljs-keyword">new</span> HashMap&lt;String, Integer&gt;();
<span class="hljs-built_in">map</span>.put(<span class="hljs-string">"startIndex"</span>,(currentPage<span class="hljs-number">-1</span>)*pageSize);
<span class="hljs-built_in">map</span>.put(<span class="hljs-string">"pageSize"</span>,pageSize);

<span class="hljs-comment">//测试</span>
UserDao mapper = sqlSession.getMapper(UserMapper.class);
List&lt;User&gt; users = mapper.selectUserByLimit(<span class="hljs-built_in">map</span>);

<span class="hljs-keyword">for</span> (User user : users) {
    System.out.println(user);
}

sqlSession.close();<span class="hljs-comment">//关闭连接</span>
}

注意优化别名问题

可以为一个包的所有类指定别名，这个别名为类名
com.kuang.pojo.User - > User
写在你的mybatis配置文件下

<!--优化别名-->
<typeAliases>
        <package name="com.Shandx.pojo"/>
</typeAliases>