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我是Java编程的初学者,很难理解循环遍历Java对象列表的概念。Java遍历对象列表
输入数据记录的形式为:
TestDataSet1 |4|01-category1|100|43|||
TestDataSet2 |4|02-category2|10044307001|0|100|2016-07-20 21:36:00|
TestDataSet3 |4|03-category3|104331|
TestDataSet4 |5|04-category4|100|2016-07-20 21:36:00|
TestDataSet5 |4|01-category1|100|43|||
TestDataSet3 |4|03-category3|104331|
为了读取基于类别中我的程序上面的记录数据,为每个类别对象名单,创建为:
List<Object> category1Orcategory2OrCategory3OrCategory4;
如果输入数据的形式,
TestDataSet1 |4|01-category1|100|43|||
TestDataSet2 |4|02-category2|10044307001|0|100|2016-07-20 21:36:00|
TestDataSet3 |4|03-category3|104331|
TestDataSet4 |4|04-category4|100|2016-07-20 21:36:00|
访问对象列表可以用:
Category1 - object.getcategory1Orcategory2OrCategory3OrCategory4().get(0);
Category2 - object.getcategory1Orcategory2OrCategory3OrCategory4().get(1);
Category3 - object.getcategory1Orcategory2OrCategory3OrCategory4().get(2);
Category4 - object.getcategory1Orcategory2OrCategory3OrCategory4().get(3);
因此,循环是可以做到:
for(int index=0 ; index = list.size(); index++){
object.getcategory1Orcategory2OrCategory3OrCategory4().get(index);
}
但有时,一些类别的数据将丢失和输入的样子:
case1:
TestDataSet1 |4|01-category1|100|43|||
TestDataSet3 |4|03-category3|104331|
TestDataSet4 |5|04-category4|100|2016-07-20 21:36:00|
或
case2:
TestDataSet1 |4|01-category1|100|43|||
TestDataSet3 |4|02-category2|104331|
TestDataSet4 |5|04-category4|100|2016-07-20 21:36:00|
可以理解的是,在case1中数据ca
Category1 - object.getcategory1Orcategory2OrCategory3OrCategory4().get(0);
Category3 - object.getcategory1Orcategory2OrCategory3OrCategory4().get(1);
Category4 - object.getcategory1Orcategory2OrCategory3OrCategory4().get(2);
或案例2:在正访问
Category1 - object.getcategor1Orcategory2OrCategory3OrCategory4().get(0);
Category2 - object.getcategory1Orcategory2OrCategory3OrCategory4().get(1);
Category4 - object.getcategory1Orcategory2OrCategory3OrCategory4().get(2);
我很困惑我如何可以使“for循环”通用覆盖所有这些情况下,通过对象的列表循环:
for(int index=0 ; index = list.size(); index++){
object.getcategory1Orcategory2OrCategory3OrCategory4().get(???);
}
的问题我不清楚。你是否尝试过重用你的第一个循环?什么地方出了错? –