Mybatis-plus的两种分页方案

底层的逻辑是写出最终执行的sql或者selectPage方法等，中间需要配置相应的page拦截器。

注意：如没有配置拦截器，直接执行就会存在total的值为0，此方法无效。

1. 基于MP的IPage接口实现

使用步骤：

引入pom配置

<dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId>
</dependency>

配置分页拦截器

@Configuration
public class MybatisPlusConfig {/*** 新的分页插件,一缓和二缓遵循mybatis的规则,需要设置 		  MybatisConfiguration#useDeprecatedExecutor = false 避免缓存出现问题*/@Beanpublic MybatisPlusInterceptor mybatisPlusInterceptor() {MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.H2));return interceptor;}
}

执行测试

@Testpublic void testSelectPage(){Page<User> page = new Page<>(0, 5);page.addOrder(OrderItem.asc("age"));page.setOptimizeCountSql(false);//关闭自动优化Page<User> userIPage = userMapper.selectPage(page, Wrappers.<User>lambdaQuery().eq(User::getAge, 19).like(User::getName, "bob"));assertThat(page).isSameAs(userIPage);log.error("总条数 -------------> {}", userIPage.getTotal());log.error("当前页数 -------------> {}", userIPage.getCurrent());log.error("当前每页显示数 -------------> {}", userIPage.getSize());List<User> records = userIPage.getRecords();assertThat(records).isNotEmpty();}

2. 基于PageHelper的第三方组件实现

引入配置

<dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><!-- pagehelper 包含该依赖存在版本冲突，因此不建议和 mp 一起混用 --><exclusions><exclusion><groupId>com.github.jsqlparser</groupId><artifactId>jsqlparser</artifactId></exclusion></exclusions>
</dependency>
<dependency><groupId>com.github.pagehelper</groupId><artifactId>pagehelper</artifactId><version>5.1.11</version>
</dependency>

配置拦截器

@Configuration
public class MyBatisPlusConfig {// 基于PageHelper@BeanPageInterceptor pageInterceptor() {PageInterceptor pageInterceptor = new PageInterceptor();Properties properties = new Properties();properties.setProperty("helperDialect", "mysql");pageInterceptor.setProperties(properties);  // 由此可进入源码，return pageInterceptor;}}

执行测试

@Test
void test() {// pagehelperMap<String, Object> params = new HashMap<>();params.put("name", "%");PageHelper.startPage(3, 2);List<User> list = userMapper.pageUser(params);System.out.println("list.size=" + info.getList().size());log.info(JSONUtil.toJsonStr(info.getList()));System.out.println("page.total=" + info.getTotal());
}
########分隔符#########
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.pimee.bootmybatisplus.mapper.UserMapper"><select id="pageUser" resultType="com.pimee.bootmybatisplus.model.User">select id, name, age, email from user<where><if test="name!=null and name!=''">name like #{name}</if></where></select>
</mapper>
########分隔符#########
@Mapper
public interface UserMapper extends BaseMapper<User> {/*** 分页列表* @return*/List<User> pageUser(Map<String, Object> params);
}