JDK动态代理示例（一个注解就能帮你完成查询）

publicinterfaceUserMapper {
@Select("select * from tb_user")
publicList<User>getUsers();
}

publicclassMapperHandlerimplementsInvocationHandler {
privateJdbcTemplatejdbcTemplate;
publicMapperHandler(JdbcTemplatejdbcTemplate) {
this.jdbcTemplate=jdbcTemplate;
    }
@OverridepublicObjectinvoke(Objectproxy, Methodmethod, Object[] args) throwsThrowable {
// 仅保留必要的步骤，如传参等细节不做演示Selectselect=method.getAnnotation(Select.class);
String[] sqls=select.value();
Stringsql=sqls[0];
ClassresultType=method.getReturnType();
// 这里就不写jdbc了，借用JdbcTemplate来执行sqlListlist=jdbcTemplate.query(sql, newBeanPropertyRowMapper<>(resultType));
returnlist;
    }
}

UserMappermapper= (UserMapper) Proxy.newProxyInstance(
UserMapper.class.getClassLoader(), 
UserMapper.class.getInterfaces(), 
newMapperInvocationHandler(jdbcTemplate));
mapper.getUsers();