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2015/4/20
周末回去想了下,hibernate、mybatis、jdbc,都行,最终定了用mybatis,谁叫它这么优雅,acvtiviti是依赖了mybatis的,就不用再引入包了;
看了配置文件,之前配置的是jpa,再配置mybatis,配置文件就显得臃肿,很乱了;用jpa吧,貌似也不赖;
再写一个Repository;
写SQL的时候用到了,知识点:
instr:instr(t.DESCRIPTION_, ‘conditionCountersign‘) > 0
mysql查询最后一条记录,不能用orderby:
需求:要取a1的最后一条数据来关联,语句如下;
解决:不能在inner join里边用order by xxx limit 1;
折中解决:用时间来限制;a1.START_TIME_>a2.START_TIME_
select distinct RES.*, a1.ID_, a2.ID_ from ACT_HI_PROCINST RES inner join ACT_HI_ACTINST a1 on (a1.PROC_INST_ID_ = RES.PROC_INST_ID_ and a1.ACT_TYPE_ != ‘endEvent‘)
inner join ACT_RU_TASK t on (a1.TASK_ID_=t.ID_ and instr(t.DESCRIPTION_, ‘conditionCountersign‘) > 0)
inner join ACT_HI_ACTINST a2 on (a1.ACT_ID_=a2.ACT_ID_ and a1.START_TIME_>a2.START_TIME_ and a2.ASSIGNEE_=‘324‘)
where RES.END_TIME_ is null
and exists (select LINK.USER_ID_ from ACT_HI_IDENTITYLINK LINK where USER_ID_ = ‘324‘ and LINK.PROC_INST_ID_ = RES.ID_) order by START_TIME_ desc;
jpa映射activiti的实体,各种报错;
好麻烦,jpa要写实体,要写HQL,原来我都写好SQL了,还要转换为HQL,hibernate真麻烦;
慢慢拷贝表字段写实体,每个实体要继承原有的entity;
先写一个测试用例,跑通了再说,别连查询都查不了,就浪费时间了;贴一些主要的代码:
实体:
Repository:
测试用例:
可以哦:
那开始慢慢写实体吧,写好再改HQL;
写好了HQL,开始测试:
报错:
Caused by: java.lang.IllegalArgumentException: node to traverse cannot be null!
摸不着头脑,先精简语句,先调通上半部分的union再说;
还是一样;
问度娘;度娘说是HQL写错了,哪里错了,她也不说,真是的;
再次精简:
还是一样;
再次精简:
还是一样;
哥,多了个左括号;继续奋战;
再加SQL:
加参数,加排序,很顺利;
另一个union问题就很多,有点绝望;
换用jdbc试试;
遇到的错误:
错误代码: 1248
Every derived table must have its own alias
解决:
select count(0) as total from (xxx);后边要带别名;
select count(0) as total from (xxx) dd;
很快就写好了,原生SQL就是好;
jdbc的dao层:
/** * 分页查询待办工作流记录 * @param involvedUser * @param firstResult * @param maxResults * @return */ public List<HistoricProcessInstanceEntity> qryUnfinishedByInvolvedUser(HistoricProcessInstanceQuery query){ StringBuilder sql = new StringBuilder(); sql.append(" select "); sql.append(HistoricProcessInstanceSQLFragment.baseColumnList()); sql.append(" from ("); sql.append("(select RES.* from ACT_HI_PROCINST RES "); sql.append("where RES.END_TIME_ is null "); sql.append(" and (exists (select LINK.USER_ID_ from ACT_HI_IDENTITYLINK LINK where USER_ID_ = ? and LINK.PROC_INST_ID_ = RES.PROC_INST_ID_)) "); sql.append(" and exists (select 1 from ACT_RU_TASK t where t.PROC_INST_ID_=RES.ID_ and t.ASSIGNEE_=? order by t.ID_ asc limit 1)) "); sql.append(" union "); sql.append(" (select distinct RES.* from ACT_HI_PROCINST RES inner join ACT_HI_ACTINST a1 on (a1.PROC_INST_ID_ = RES.PROC_INST_ID_ and a1.ACT_TYPE_ != ‘endEvent‘) "); sql.append(" inner join ACT_RU_TASK t on (a1.TASK_ID_=t.ID_ and instr(t.DESCRIPTION_, ‘conditionCountersign‘) > 0) "); sql.append(" inner join ACT_HI_ACTINST a2 on (a1.ACT_ID_=a2.ACT_ID_ and a1.START_TIME_>a2.START_TIME_ and a2.ASSIGNEE_=?) "); sql.append(" where RES.END_TIME_ is null "); sql.append(" and exists (select LINK.USER_ID_ from ACT_HI_IDENTITYLINK LINK where USER_ID_ = ? and LINK.PROC_INST_ID_ = RES.ID_)) "); sql.append("order by START_TIME_ desc) dd "); List<Object> param = new ArrayList<Object>(); param.add(query.getInvolvedUser()); param.add(query.getInvolvedUser()); param.add(query.getInvolvedUser()); param.add(query.getInvolvedUser()); String countSql = PageUtils.getCountSQL(sql.toString()); logger.info("About to excute sql=\n{}\n{}", countSql, BaseUtils.printList(param)); Integer total = baseDao.getJdbcTemplate().queryForObject(countSql, param.toArray(), Integer.class); query.setTotalRecord(total); // 分页设置 PageUtils.buildPageSqlForMysql(sql, query); logger.info(" About to excute sql=\n{}\n{}", sql.toString(), BaseUtils.printList(param)); List<HistoricProcessInstanceEntity> datas = baseDao.getJdbcTemplate().query(sql.toString(), param.toArray(), new BeanPropertyRowMapper<HistoricProcessInstanceEntity>(HistoricProcessInstanceEntity.class)); return datas; }
启动项目测试:
严重: Servlet.service() for servlet [spring] in context with path [] threw exception [Handler processing failed; nested exception is java.lang.NoSuchMethodError: com.sinotaiyo.srpm.activiti.DetailBuilder.BuildWorkflowDetailByEntity(Lorg/activiti/engine/impl/persistence/entity/HistoricProcessInstanceEntity;)Lcom/sinotaiyo/srpm/activiti/WorkflowDetail;] with root cause
java.lang.NoSuchMethodError: com.sinotaiyo.srpm.activiti.DetailBuilder.BuildWorkflowDetailByEntity(Lorg/activiti/engine/impl/persistence/entity/HistoricProcessInstanceEntity;)Lcom/sinotaiyo/srpm/activiti/WorkflowDetail;
方法是写好的,debug进去是用代理模式;
javap –s DetailBuilder
貌似一样的啊;
折腾了好久,用Run As Server里边的tomcat就可以,但用maven插件的方式启动就报错;
为啥呢?
优化到此为止,告一段落。
疑问:
1、jpa的注解方式写DAO层可以用原生SQL吗?HQL是这样的:
2、activiti的表字段和属性名虽然不一样,但还是可以识别,不算折磨人,为什么不能一样呢?一样不是更好吗?所有地方都可以拷贝,不用拷贝了修改,保留下划线可以理解,要是怕字段过长的话,别定那么长的字段就可以了,至少要保持一致,一致之后很多自动化的事情就好办了,比如写代码生成器;
3、设计良好的数据库,即使再复杂的查询也应该是很好写,为何这里的待办查询这么恐怖?
总结:
1、 新入职,接手已有项目,就是这么坎坷,习惯就好;
2、 论测试的重要性,一个语句测多少遍才测通啊,写测试还是非常有必要的,负责任的提现,但之前公司的开发人员,工作1年就当技术主管,代码都没写几行就主管,真心无语,还有个工作1年就封为架构师,写个JavaBean属性全是public,都只是加班积极点,爱装13,我也是醉了;
3、 排错的简单做法就是先做减法再做加法,不用开根号,呵呵简单吧;
4、 能用SQL一次做完的事情就用SQL做,像下图这种,完全可以在语句里边过滤排序吧;
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原文地址:http://www.cnblogs.com/yejq/p/4451167.html