大神帮我解释下下面这段代码 谢谢啦,拜托

大神帮我解释下下面这段代码 谢谢啦,拜托

public String getByTrainingOrCompetitionID()  throws Exception
    {

          zheJiuSheZhiList = dao.getList(TrainingOrCompetitionID);
        if(zheJiuSheZhiList.size()>0)
        {
            zheJiuSheZhi=zheJiuSheZhiList.get(0);
        }
          return SUCCESS;
    } 


dao.getList(TrainingOrCompetitionID);获取一个列表
下面就是判断这个列表是否有东西,如果有,就取出第一个

这段代码执行dao.getList方法,一般是去数据库里查找信息,查找到的信息是一个集合,zheJiuSheZhiList.get(0)意思就是拿出这个集合里面的第一个对象,然后返回success

zheJiuSheZhiList = dao.getList(TrainingOrCompetitionID);根据TrainingOrCompetitionID获得结果集
if(zheJiuSheZhiList.size()>0)//判断是否有数据
{
zheJiuSheZhi=zheJiuSheZhiList.get(0);获取第一条记录赋值给zheJiuSheZhi
}
return SUCCESS;方法返回成功

dao.getList(TrainingOrCompetitionID);
有东西就取dao.getList(TrainingOrCompetitionID)的第一个,返回success

zheJiuSheZhiList = dao.getList(TrainingOrCompetitionID);根据TrainingOrCompetitionID获得结果集
if(zheJiuSheZhiList.size()>0)//判断是否有数据
{
zheJiuSheZhi=zheJiuSheZhiList.get(0);获取第一条记录赋值给zheJiuSheZhi
}
return SUCCESS;方法返回成功

此时再看这个方法是不是觉得没有什么了呢?根据传入的ID查询数据并设置zheJiuSheZhi为第一个查询得到的结果,没有就不设置,查询得到或没有都返回success