前言
公司架构层面推 Mybatis-plus，这里花半天学习下，记录点笔记。内容包括：
- 使用
- 查询构造器使用
- 分页插件使用
- 代码生成
- 技巧
- 打印完整sql方便验证结论
- Mybatis-plus 新的官网域名有问题，用这个 https://baomidou.com/getting-started/
- 其他
- 本来想把代码推到代码仓的，但是网络有问题…后面补
- 使用 Spring Boot 3 集成
完整sql打印
为了测试效果，用了官方推荐的sql日志依赖，官方没有提到的是这个依赖兼容 druid，而且无侵入。用的是代理数据库驱动的方式。重点是引入依赖不需要任何配置就能用起来
<dependency><groupId>com.github.gavlyukovskiy</groupId><artifactId>p6spy-spring-boot-starter</artifactId><version>1.11.0</version></dependency>
单表CRUD 快速支持
以下代码都可以用代码生成器做出来，后文贴出所有配置
public interface ActivityInfoMapper extends BaseMapper<ActivityInfo> {}
@Data
@TableName("xx_activity_info")
public class ActivityInfo implements Serializable {private static final long serialVersionUID = 1L;@TableId(value = "id", type = IdType.AUTO)private Integer id;@TableField("name")private String name;
}
复杂sql代码化
以下sql映射
SELECT id,name FROM tm_activity_info
WHERE (name = 'A' AND (name LIKE '%A%' OR name LIKE '%B%' OR name LIKE '%C%') AND name = 'D');
@Testpublic void testUsingNested() {// 查询条件LambdaQueryWrapper<ActivityInfo> wrapper = Wrappers.lambdaQuery();wrapper.eq(ActivityInfo::getName, "A").nested(w ->w.like(ActivityInfo::getName, "A").or().like(ActivityInfo::getName, "B").or().like(ActivityInfo::getName, "C")).eq(ActivityInfo::getName, "D");activityInfoMapper.selectList(wrapper);}
分页插件
配置
@Configuration
@MapperScan("com.james.initializr.mapper")
public class MybatisPlusConfig {@Beanpublic MybatisPlusInterceptor mybatisPlusInterceptor() {MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL)); // 如果配置多个插件, 切记分页最后添加return interceptor;}
}
以下sql映射
SELECT id,name FROM xx_activity_info LIMIT 2,2;
@Testpublic void testGetAllRecordsWhenPage() {IPage<ActivityInfo> pageQuery = new Page<>(2, 2);// pageQuery.setSize(-1); 如果加上行代码，表示查所有数据IPage<ActivityInfo> pageResult = activityInfoMapper.selectPage(pageQuery, null);log(pageResult, "分页用例");}private void log(IPage<ActivityInfo> page, String remark) {logger.info("==== {} ==== 记录总数={} 一页数量={} 总页数={} 当前页={} ",remark, page.getTotal(), page.getSize(), page.getPages(), page.getCurrent());page.getRecords().forEach(r -> logger.info(r.toString()));logger.info("==== {} ====", remark);}
代码生成
用的最新版的生成方式，并列出官网没有给齐的依赖声明
@Testpublic void test() {FastAutoGenerator.create(url, username, password).globalConfig(builder -> {String dateStr = new SimpleDateFormat("MM月dd日hh时mm分").format(new Date());String dir = "D://mp-gen/" + dateStr + "/";builder.author("yangchenghan").outputDir(dir) ; // 指定输出目录}).packageConfig(builder ->builder.parent("com.james.initializr") // 包名.entity("entity").mapper("mapper").xml("mapperXml")).strategyConfig(builder -> {builder.addInclude("xx_activity_info") // 设置需要生成的表名.addTablePrefix("xx_", "xxx_").entityBuilder().enableTableFieldAnnotation().serviceBuilder().disable().controllerBuilder().disable().mapperBuilder().enableBaseColumnList().enableBaseResultMap();}).templateEngine(new FreemarkerTemplateEngine()).execute();}
默认的交互方式是弹出文件目录，自行复制到项目中
依赖声明
<properties><java.version>17</java.version></properties><dependencyManagement><dependencies><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-bom</artifactId><version>3.5.11</version><type>pom</type><scope>import</scope></dependency></dependencies></dependencyManagement><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid-spring-boot-3-starter</artifactId><version>1.2.22</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.27</version></dependency><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-spring-boot3-starter</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-logging</artifactId></dependency><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter-test</artifactId></dependency><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-jsqlparser</artifactId></dependency><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-generator</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-freemarker</artifactId></dependency><dependency><groupId>com.github.gavlyukovskiy</groupId><artifactId>p6spy-spring-boot-starter</artifactId><version>1.11.0</version></dependency></dependencies>
后记
一开始接触 Mybatis-plus，应该是5年前刚入行，那会 QueryWrapper 被到处封装和使用，污染了 Service层。
目前依旧坚持只在mapper层用，其他高级的功能需要用到再持续记录。
