Aggregation.group分组汇总

1.1 初始化数据

 mongoTemplate.save(new Role("zhang1",5));  mongoTemplate.save(new Role("zhang2",6));  mongoTemplate.save(new Role("zhang3",12));  mongoTemplate.save(new Role("zhang4",14));  mongoTemplate.save(new Role("zhang5",23));  mongoTemplate.save(new Role("zhang1",6));