# Part02-MyBatis-Plus的使用
blog
│ pom.xml
│
├─src
│ └─main
│ ├─java
│ │ └─org
│ │ └─myslayers
│ │ │ CodeGenerator
│ │ │
│ │ ├─config
│ │ │ MyBatisPlusConfig.java
│ │ │
│ │ ├─service
│ │ │ │ PostService.java
│ │ │ │
│ │ │ └─impl
│ │ │ PostServiceImpl.java
│ │ │
│ │ ├─mapper
│ │ │ │ PostMapper.java
│ │ │ │
│ │ │ └─impl
│ │ │ PostMapper.xml
# 2.1 MP 环境
pom.xml：项目依赖，【mybatis-plus-boot-starter、p6spy】
<dependencies>
<!--mp、druid、mysql、mp-generator（MyBatis-Plus 从 3.0.3后移除了代码生成器与模板引擎的默认依赖）、MP支持的SQL分析器-->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.2.0</version>
</dependency>
<!-- <dependency>-->
<!-- <groupId>com.alibaba</groupId>-->
<!-- <artifactId>druid-spring-boot-starter</artifactId>-->
<!-- <version>1.1.10</version>-->
<!-- </dependency>-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-generator</artifactId>
<version>3.2.0</version>
</dependency>
<dependency>
<groupId>p6spy</groupId>
<artifactId>p6spy</artifactId>
<version>3.8.6</version>
</dependency>
</dependencies>
application.yml：配置文件，【识别 Mapper 层】
mybatis-plus:
mapper-locations: classpath*:/mapper/**Mapper.xml
# 2.2 代码生成器
- CodeGenerator.java：项目依赖，【mybatis-plus-boot-starter、mysql-connector-java、mybatis-plus-generator、druid-spring-boot-starter、spring-boot-starter-freemarker】
// 演示例子，执行 main 方法控制台输入模块表名回车自动生成对应项目目录中
public class CodeGenerator {
/**
* <p>
* 读取控制台内容
* </p>
*/
public static String scanner(String tip) {
Scanner scanner = new Scanner(System.in);
StringBuilder help = new StringBuilder();
help.append("请输入" + tip + "：");
System.out.println(help.toString());
if (scanner.hasNext()) {
String ipt = scanner.next();
if (StringUtils.isNotEmpty(ipt)) {
return ipt;
}
}
throw new MybatisPlusException("请输入正确的" + tip + "！");
}
public static void main(String[] args) {
// 代码生成器
AutoGenerator mpg = new AutoGenerator();
// 全局配置
GlobalConfig gc = new GlobalConfig();
String projectPath = System.getProperty("user.dir");
gc.setOutputDir(projectPath + "/src/main/java");
gc.setAuthor("myslayers");
gc.setOpen(false);
// gc.setSwagger2(true); 实体属性 Swagger2 注解
gc.setServiceName("%sService");
mpg.setGlobalConfig(gc);
// 数据源配置
DataSourceConfig dsc = new DataSourceConfig();
dsc.setUrl(
"jdbc:mysql://localhost:3306/xblog?useUnicode=true&useSSL=false&characterEncoding=utf8&serverTimezone=UTC");
// dsc.setSchemaName("public");
dsc.setDriverName("com.mysql.jdbc.Driver");
dsc.setUsername("root");
dsc.setPassword("4023615");
mpg.setDataSource(dsc);
// 包配置
PackageConfig pc = new PackageConfig();
pc.setModuleName(null);
pc.setParent("org.myslayers");
mpg.setPackageInfo(pc);
// 自定义配置
InjectionConfig cfg = new InjectionConfig() {
@Override
public void initMap() {
// to do nothing
}
};
// 如果模板引擎是 freemarker
String templatePath = "/templates/mapper.xml.ftl";
// 如果模板引擎是 velocity
// String templatePath = "/templates/mapper.xml.vm";
// 自定义输出配置
List<FileOutConfig> focList = new ArrayList<>();
// 自定义配置会被优先输出
focList.add(new FileOutConfig(templatePath) {
@Override
public String outputFile(TableInfo tableInfo) {
// 自定义输出文件名 ， 如果你 Entity 设置了前后缀、此处注意 xml 的名称会跟着发生变化！！
return projectPath + "/src/main/resources/mapper/"
+ "/" + tableInfo.getEntityName() + "Mapper" + StringPool.DOT_XML;
}
});
cfg.setFileOutConfigList(focList);
mpg.setCfg(cfg);
// 配置模板
TemplateConfig templateConfig = new TemplateConfig();
// 配置自定义输出模板
//指定自定义模板路径，注意不要带上.ftl/.vm, 会根据使用的模板引擎自动识别
// templateConfig.setEntity("templates/entity2.java");
// templateConfig.setService();
// templateConfig.setController();
templateConfig.setXml(null);
mpg.setTemplate(templateConfig);
// 策略配置
StrategyConfig strategy = new StrategyConfig();
strategy.setNaming(NamingStrategy.underline_to_camel);
strategy.setColumnNaming(NamingStrategy.underline_to_camel);
// 你自己的父类实体,没有就不用设置!
strategy.setSuperEntityClass("org.myslayers.entity.BaseEntity");
strategy.setEntityLombokModel(true);
strategy.setRestControllerStyle(true);
// 你自己的父类控制器,没有就不用设置!
strategy.setSuperControllerClass("org.myslayers.controller.BaseController");
strategy.setInclude(scanner("表名，多个英文逗号分割").split(","));
strategy.setSuperEntityColumns("id", "created", "modified", "status");
strategy.setControllerMappingHyphenStyle(true);
strategy.setTablePrefix(pc.getModuleName() + "_");
mpg.setStrategy(strategy);
mpg.setTemplateEngine(new FreemarkerTemplateEngine());
mpg.execute();
}
}
# 2.3 分页插件
MyBatisPlusConfig.java：配置类，【SpringBoot 的使用方式】
@Configuration
@EnableTransactionManagement
@MapperScan("org.myslayers.mapper")
public class MyBatisPlusConfig {
/**
* 分页插件
*/
@Bean
public PaginationInterceptor paginationInterceptor() {
PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
return paginationInterceptor;
}
}
# 2.4 执行 SQL 分析打印
spy.properties：配置文件，【该功能依赖 p6spy 组件，其中 datasource、freemarker、mybatis-plus 的配置】
spring:
datasource:
# driver-class-name: com.mysql.cj.jdbc.Driver
driver-class-name: com.p6spy.engine.spy.P6SpyDriver
url: jdbc:p6spy:mysql://127.0.0.1:3306/xblog?useUnicode=true&useSSL=false&characterEncoding=utf8&serverTimezone=UTC
username: root
password: 123456
freemarker:
settings:
classic_compatible: true
datetime_format: yyyy-MM-dd HH:mm
number_format: 0.##
spy.properties：配置文件，【p6spy 组件对应的 spy.properties 配置】
#3.2.1以下使用或者不配置
module.log=com.p6spy.engine.logging.P6LogFactory,com.p6spy.engine.outage.P6OutageFactory
# 自定义日志打印
logMessageFormat=com.baomidou.mybatisplus.extension.p6spy.P6SpyLogger
#日志输出到控制台
appender=com.baomidou.mybatisplus.extension.p6spy.StdoutLogger
# 使用日志系统记录 sql
#appender=com.p6spy.engine.spy.appender.Slf4JLogger
# 设置 p6spy driver 代理
deregisterdrivers=true
# 取消JDBC URL前缀
useprefix=true
# 配置记录 Log 例外,可去掉的结果集有error,info,batch,debug,statement,commit,rollback,result,resultset.
excludecategories=info,debug,result,batch,resultset
# 日期格式
dateformat=yyyy-MM-dd HH:mm:ss
# 实际驱动可多个
#driverlist=org.h2.Driver
# 是否开启慢SQL记录
outagedetection=true
# 慢SQL记录标准 2 秒
outagedetectioninterval=2
# 2.5 条件构造器
PostService.java：业务层接口
public interface PostService extends IService<Post> {
IPage<PostVo> selectPosts(Page page, Long categoryId, Long userId, Integer level, Boolean recommend, String order);
}
PostServiceImpl.java：业务层实现
@Service
public class PostServiceImpl extends ServiceImpl<PostMapper, Post> implements PostService {
@Autowired
PostMapper postMapper;
@Override
public IPage<PostVo> selectPosts(Page page, Long categoryId, Long userId, Integer level, Boolean recommend, String order) {
if (level == null) level = -1;
QueryWrapper wrapper = new QueryWrapper<Post>()
.eq(categoryId != null, "category_id", categoryId)
.eq(userId != null, "user_id", userId)
.eq(level == 0, "level", 0)
.gt(level > 0, "level", 0)
.orderByDesc(order != null, order);
return postMapper.selectPosts(page, wrapper);
}
@Override
public PostVo selectOnePost(QueryWrapper<Post> warapper) {
return postMapper.selectOnePost(warapper);
}
}
PostMapper.java：数据层接口
public interface PostMapper extends BaseMapper<Post> {
IPage<PostVo> selectPosts(Page page, @Param(Constants.WRAPPER) QueryWrapper<Post> wrapper);
}
PostMapper.xml：数据层实现
<select id="selectPosts" resultType="org.myslayers.vo.PostVo">
SELECT p.id,
p.title,
p.content,
p.edit_mode,
p.category_id,
p.user_id,
p.vote_up,
p.vote_down,
p.view_count,
p.comment_count,
p.recommend,
p.level,
p.status,
p.created,
p.modified,
u.id AS authorId,
u.username AS authorName,
u.avatar AS authorAvatar,
c.id AS categoryId,
c.name AS categoryName
FROM m_post p
LEFT JOIN m_user u ON p.user_id = u.id
LEFT JOIN m_category c ON p.category_id = c.id
${ew.customSqlSegment}
</select>