SpringBoot使用mybatis-plus代码生成器初始化项目(含分页查询示例)

spring-boot版本：2.1.5.RELEASE
mybatis-plus版本：2.1.9
自己搭建项目基础部分时对比了mybatis和mybatis-plus的代码生成器，发现后者生成的类更加全面，简单记录下使用过程。

生成项目

可以使用idea创建一个springboot的maven项目
File=>New=>Project=>Spring Initializr
，或者直接在官网上生成。
简单填下项目名、包名之类就行

引入依赖

<dependencies>
    <!-- springboot基础依赖 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <!-- 数据库连接 -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
    <!-- lombok省略get/set方法 -->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>

    <!--MyBatis-plus-->
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>2.1.9</version>
    </dependency>
    
</dependencies>

配置文件（application.yml）

server:
  port: 8080

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/dbgirl?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
    username: root
    password: 123456

mybatis-plus:
  # 如果是放在src/main/java目录下 classpath:/com/yourpackage/*/mapper/*Mapper.xml
  # 如果是放在resource目录 classpath:/mapper/*Mapper.xml
  mapper-locations: classpath:/com/atmoon/*/mapper/xml/*Mapper.xml
  #实体扫描，多个package用逗号或者分号分隔
  typeAliasesPackage: com.atmoon.demo.entity
  global-config:
    #主键类型  0:"数据库ID自增", 1:"用户输入ID",2:"全局唯一ID (数字类型唯一ID)", 3:"全局唯一ID UUID";
    id-type: 0
    #字段策略 0:"忽略判断",1:"非 NULL 判断"),2:"非空判断"
    field-strategy: 2
    #驼峰下划线转换
    db-column-underline: true
    #刷新mapper 调试神器
    refresh-mapper: true
  configuration:
    #配置返回数据库(column下划线命名&&返回java实体是驼峰命名)，自动匹配无需as（没开启这个，SQL需要写as： select user_id as userId）
    map-underscore-to-camel-case: true
    cache-enabled: false
    #配置JdbcTypeForNull, oracle数据库必须配置
    jdbc-type-for-null: 'null'

引入代码生成器

放到test包下，直接运行就行。属性根据自己需要可以做些调整。

package com.atmoon.demo;

import com.baomidou.mybatisplus.enums.IdType;
import com.baomidou.mybatisplus.generator.AutoGenerator;
import com.baomidou.mybatisplus.generator.config.DataSourceConfig;
import com.baomidou.mybatisplus.generator.config.GlobalConfig;
import com.baomidou.mybatisplus.generator.config.PackageConfig;
import com.baomidou.mybatisplus.generator.config.StrategyConfig;
import com.baomidou.mybatisplus.generator.config.rules.DbType;
import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.core.env.Environment;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class GeneratorServiceEntity {

    @Autowired
    private Environment environment;

    @Value("${spring.datasource.url}")
    private String dbUrl;

    @Test
    public void generateCode() {
        String packageName = "com.atmoon.demo";
        String[] s = new String[]{"department", "girl"};
        generateByTables(packageName, s);
    }

    private void generateByTables(boolean serviceNameStartWithI, String packageName, String... tableNames) {
        GlobalConfig config = new GlobalConfig();
        DataSourceConfig dataSourceConfig = new DataSourceConfig();
        dataSourceConfig.setDbType(DbType.MYSQL)
                .setUrl(environment.getProperty("spring.datasource.url"))
                .setUsername(environment.getProperty("spring.datasource.username"))
                .setPassword(environment.getProperty("spring.datasource.password"))
                .setDriverName("com.mysql.cj.jdbc.Driver");
        StrategyConfig strategyConfig = new StrategyConfig();
        strategyConfig
                .setCapitalMode(true)
                // 生成实体类使用lombok模式
                .setEntityLombokModel(true)
                .setDbColumnUnderline(true)
                // 表名下划线转驼峰
                .setNaming(NamingStrategy.underline_to_camel)
                // 需要生成全部表时去掉这一行
                .setInclude(tableNames);//修改替换成你需要的表名，多个表名传数组
        config.setActiveRecord(false)
                .setAuthor("at-moon")
                // 直接设置你代码保存的位置就不用复制了
                .setOutputDir("D:\\IdeaProjects\\demo\\src\\main\\java")
                .setFileOverride(true)
                // 设置主键类型
                .setIdType(IdType.AUTO)
                // 是否开启二级缓存
                .setEnableCache(false);
        if (!serviceNameStartWithI) {
            config.setServiceName("%sService");
        }
        new AutoGenerator().setGlobalConfig(config)
                .setDataSource(dataSourceConfig)
                .setStrategy(strategyConfig)
                .setPackageInfo(
                        new PackageConfig()
                                .setParent(packageName)
                                .setController("controller")
                                .setEntity("entity")
                ).execute();
    }

    private void generateByTables(String packageName, String... tableNames) {
        generateByTables(true, packageName, tableNames);
    }
}

生成后的代码包含以下部分(这里生成了两个表对应的类，参考生成器中注释)

直接启动报错（注入mapper）

Unsatisfied dependency expressed through field ‘baseMapper’; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException:
No qualifying bean of type ‘com.atmoon.demo.mapper.GirlMapper’ available: expected at least 1 bean which qualifies as autowire candidate.

原因是没有扫描mapper对应的xml
需要在启动类中加入注解MapperScan

@SpringBootApplication
@MapperScan("com.atmoon.*.mapper")
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

分页查询示例

controller

@Controller
@RequestMapping("/girl")
public class GirlController {

    @Autowired
    private IGirlService girlService;

    @GetMapping("/list")
    @ResponseBody
    public List<Girl> queryStaffByAge(Page<Girl> page) {
        page = girlService.queryGirl(page,null);
        // 总行数
        int total = page.getTotal();
        return page.getRecords();
    }

}

service

@Service
public class GirlServiceImpl extends ServiceImpl<GirlMapper, Girl> implements IGirlService {

    @Autowired
    GirlMapper girlMapper;

    @Override
    public Page<Girl> queryGirl(Page<Girl> page, String city) {
        return page.setRecords(girlMapper.queryGirl(page,city));
    }
}

mapper

public interface GirlMapper extends BaseMapper<Girl> {

    /**
     * @param page
     * @param city
     * @return
     */
    List<Girl> queryGirl(Page<Girl> page,@Param("city")String city);
}

xml

<select id="queryGirl" resultType="com.atmoon.demo.entity.Girl">
   SELECT * FROM girl WHERE 1 = 1
    <if test=" city != null and city != ''">
        city=#{city}
    </if>
</select>

启动后访问接口报错

org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.atmoon.demo.mapper.GirlMapper.queryGirl

首先检查yml配置中mybatis-plus:mapper-locations是否正确

mybatis-plus:
  # 如果是放在src/main/java目录下 classpath:/com/yourpackage/*/mapper/*Mapper.xml
  # 如果是放在resource目录 classpath:/mapper/*Mapper.xml
  mapper-locations: classpath:/com/atmoon/*/mapper/xml/*Mapper.xml
  

如果用的idea，默认不会扫描src目录下的资源文件
在pom文件中需要加入(build下)

<resources>
	<resource>
	    <directory>src/main/java</directory>
	    <includes>
	        <include>**/*.xml</include>
	    </includes>
	</resource>
</resources>

重启后访问成功但数据未分页

需要引入分页插件

@EnableTransactionManagement
@Configuration
public class MybatisPlusConfig {

    /**
     * 分页插件
     */
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        return new PaginationInterceptor();
    }
}

小结

mybatis-plus的引入基本就结束了，引入过程中有遇到问题可以留言。