解决
检查配置 启动类上加入
@MapperScan(basePackages = "com.xxx.mapper")

 

一个坑：使用mybatis-plus时不能使用自带的SqlSessionFactory，要使用MybatisSqlSessionFactory，在配置类中加入如下配置（springboot）

  @Bean(name = "icspdbSessionFactory")
    // @Qualifier表示查找Spring容器中名字为test1DataSource的对象
    public SqlSessionFactory test2SqlSessionFactory(@Qualifier("icspdbDataSource") DataSource datasource)
            throws Exception {
//        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
//        bean.setDataSource(datasource);
//
//        org.apache.ibatis.session.Configuration configuration=new org.apache.ibatis.session.Configuration();
//        configuration.setCallSettersOnNulls(true);
//        configuration.setLogImpl(org.apache.ibatis.logging.stdout.StdOutImpl.class);
//        bean.setConfiguration(configuration);

        MybatisSqlSessionFactoryBean bean = new MybatisSqlSessionFactoryBean();
        bean.setDataSource(datasource);

       MybatisConfiguration configuration=new MybatisConfiguration();
        configuration.setCallSettersOnNulls(true);
        configuration.setLogImpl(org.apache.ibatis.logging.stdout.StdOutImpl.class);
        configuration.setMapUnderscoreToCamelCase(false);
        bean.setConfiguration(configuration);


        bean.setMapperLocations(
                // 设置mybatis的xml所在位置
                new PathMatchingResourcePatternResolver().getResources("classpath:mapper/*.xml"));
        return bean.getObject();
    }