MyBatis 实战：根据性别分组统计平均薪资 - 示例代码

//\u0020定义一个接口\npublic\u0020interface\u0020EmployeeMapper\u0020{\n\t//\u0020根据性别分组统计平均薪资\n\t@Select("SELECT\u0020gender,\u0020AVG(salary)\u0020AS\u0020averageSalary\u0020FROM\u0020employee\u0020GROUP\u0020BY\u0020gender")\n\tList<Map<String,\u0020Object>>\u0020getAverageSalaryByGender();\n}\n\n//\u0020测试代码\npublic\u0020class\u0020MyBatisTest\u0020{\n\n\tpublic\u0020static\u0020void\u0020main(String[]\u0020args)\u0020{\n\t //\u0020创建一个MyBatis的配置对象\n\t Configuration\u0020configuration\u0020=\u0020new\u0020Configuration();\n\t //\u0020设置数据库连接信息\n\t configuration.setJdbcUrl("jdbc:mysql://localhost:3306/test");\n\t configuration.setJdbcUsername("root");\n\t configuration.setJdbcPassword("password");\n\t //\u0020创建一个SqlSessionFactory对象\n\t SqlSessionFactory\u0020sqlSessionFactory\u0020=\u0020new\u0020SqlSessionFactoryBuilder().build(configuration);\n\t //\u0020创建一个SqlSession对象\n\t try\u0020(SqlSession\u0020sqlSession\u0020=\u0020sqlSessionFactory.openSession())\u0020{\n\t //\u0020获取EmployeeMapper接口的实现类对象\n\t EmployeeMapper\u0020employeeMapper\u0020=\u0020sqlSession.getMapper(EmployeeMapper.class);\n\t //\u0020调用接口方法获取结果\n\t List<Map<String,\u0020Object>>\u0020result\u0020=\u0020employeeMapper.getAverageSalaryByGender();\n\t //\u0020打印结果\n\t for\u0020(Map<String,\u0020Object>\u0020row\u0020:\u0020result)\u0020{\n\t System.out.println("Gender:\u0020"\u0020+\u0020row.get("gender")\u0020+\u0020",\u0020Average\u0020Salary:\u0020"\u0020+\u0020row.get("averageSalary"));\n\t }\n\t }\n\t}\n}