mybatis-plus:
? mapper-locations: classpath:mapper/*.xml

@Repository
public interface UserMapper extends BaseMapper<User> {
?? ??? ?// 使函數參數對應xml中的參數wxNickName
? ? List<User> selectByName(@Param("wxNickName") String name);
}

<?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.zhou.usercenter.dao.user.UserMapper">
? ? <select id="selectByName" resultType="com.zhou.usercenter.domain.entity.user.User">
? ? ? ? select * from user
? ? ? ? <where>
? ? ? ? ? ? <if test="wxNickName != null and wxNickName != ''">
? ? ? ? ? ? ? ? wx_nickname like CONCAT('%',#{wxNickName},'%');
? ? ? ? ? ? </if>
? ? ? ? </where>
? ? </select>
</mapper>

@SpringBootTest
class UserCenterApplicationTests {
? ? @Autowired
? ? UserMapper userMapper;
? ? @Test
? ? void contextLoads() {
? ? ? ? List<User> users = userMapper.selectByName("杰倫");
? ? ? ? System.out.println(users);
? ? }
}

public class MybatisSqlSessionFactoryBuilder extends SqlSessionFactoryBuilder {
    public SqlSessionFactory build(Configuration configuration) {
            // ... 省略若干行 
            if (globalConfig.isEnableSqlRunner()) {
                new SqlRunnerInjector().inject(configuration);
            }
            // ... 省略若干行 
            return sqlSessionFactory;
        }
}

public class MybatisConfiguration extends Configuration {
    /**
     * Mapper 注冊
     */
    protected final MybatisMapperRegistry mybatisMapperRegistry = new MybatisMapperRegistry(this);
    // ....
 
    /**
     * 初始化調用
     */
    public MybatisConfiguration() {
        super();
        this.mapUnderscoreToCamelCase = true;
        languageRegistry.setDefaultDriverClass(MybatisXMLLanguageDriver.class);
    }
 
    /**
     * MybatisPlus 加載 SQL 順序：
     * <p> 1、加載 XML中的 SQL </p>
     * <p> 2、加載 SqlProvider 中的 SQL </p>
     * <p> 3、XmlSql 與 SqlProvider不能包含相同的 SQL </p>
     * <p>調整后的 SQL優(yōu)先級：XmlSql > sqlProvider > CurdSql </p>
     */
    @Override
    public void addMappedStatement(MappedStatement ms) {
        // ...
    }
    
    // ... 省略若干行 
    /**
     * 使用自己的 MybatisMapperRegistry
     */
    @Override
    public <T> void addMapper(Class<T> type) {
        mybatisMapperRegistry.addMapper(type);
    }
    // .... 省略若干行 
}

public class MybatisMapperRegistry extends MapperRegistry {
    @Override
    public <T> void addMapper(Class<T> type) {
        // ... 省略若干行 
        MybatisMapperAnnotationBuilder parser = new MybatisMapperAnnotationBuilder(config, type);
        parser.parse();
        // ... 省略若干行 
    }
}

public class MybatisMapperAnnotationBuilder extends MapperAnnotationBuilder {
    @Override
    public void parse() {
        //... 省略若干行 
        for (Method method : type.getMethods()) {
            /** for循環(huán)代碼, MP判斷method方法是否是@Select @Insert等mybatis注解方法**/
            parseStatement(method);
            InterceptorIgnoreHelper.initSqlParserInfoCache(cache, mapperName, method);
            SqlParserHelper.initSqlParserInfoCache(mapperName, method);
        }
        /** 這2行代碼, MP注入默認的方法列表**/
        if (GlobalConfigUtils.isSupperMapperChildren(configuration, type)) {
            GlobalConfigUtils.getSqlInjector(configuration).inspectInject(assistant, type);
        }
        //... 省略若干行 
    }
 
    @Override
    public void inspectInject(MapperBuilderAssistant builderAssistant, Class<?> mapperClass) {
        Class<?> modelClass = extractModelClass(mapperClass);
        //... 省略若干行 
        List<AbstractMethod> methodList = this.getMethodList(mapperClass);
        TableInfo tableInfo = TableInfoHelper.initTableInfo(builderAssistant, modelClass);
        // 循環(huán)注入自定義方法
        methodList.forEach(m -> m.inject(builderAssistant, mapperClass, modelClass, tableInfo));
        mapperRegistryCache.add(className);
    }
}
public class DefaultSqlInjector extends AbstractSqlInjector { 
    @Override
    public List<AbstractMethod> getMethodList(Class<?> mapperClass) {
        return Stream.of(
            new Insert(),
            //... 省略若干行 
            new SelectPage()
        ).collect(toList());
    }
}

/**
 * 根據ID 查詢一條數據
 */
public class SelectById extends AbstractMethod {
    @Override
    public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
        /** 定義 mybatis xml method id, 對應 <id="xyz"> **/
        SqlMethod sqlMethod = SqlMethod.SELECT_BY_ID;
        /** 構造id對應的具體xml片段 **/
        SqlSource sqlSource = new RawSqlSource(configuration, String.format(sqlMethod.getSql(),
            sqlSelectColumns(tableInfo, false),
            tableInfo.getTableName(), tableInfo.getKeyColumn(), tableInfo.getKeyProperty(),
            tableInfo.getLogicDeleteSql(true, true)), Object.class);
        /** 將xml method方法添加到mybatis的MappedStatement中 **/
        return this.addSelectMappedStatementForTable(mapperClass, getMethod(sqlMethod), sqlSource, tableInfo);
    }
}

public class YourSqlSessionFactoryBean extends SqlSessionFactoryBean implements ApplicationContextAware { 
    private Resource[] mapperLocations; 
    @Override
    public void setMapperLocations(Resource... mapperLocations) {
        super.setMapperLocations(mapperLocations);
        /** 暫存使用mybatis原生定義的mapper xml文件路徑**/
        this.mapperLocations = mapperLocations;
    }
 
    /**
     * {@inheritDoc}
     */
    @Override
    public void afterPropertiesSet() throws Exception {
        ConfigurableListableBeanFactory beanFactory = getBeanFactory();
        /** 只需要通過將自定義的方法構造成xml resource和原生定義的Resource一起注入到mybatis中即可, 這樣就可以實現(xiàn)MP的自定義動態(tài)SQL和原生SQL的共生關系**/
        this.setMapperLocations(InjectMapper.getMapperResource(this.dbType, beanFactory, this.mapperLocations));
        super.afterPropertiesSet();
    }
}