我对Java相当陌生，目前正在开发一个小型应用程序，该应用程序可以存储和处理从文本文件读取的城市数据。我有一个DAOTextImpl类，应该从文本文件中读取它，选择所有数据行并将它们存储在要排序的ArrayList中。到目前为止，我只能选择要存储的4行数据中的3行。
有人可以看看为什么只拾取和存储前两套城市数据（2015和2016年）吗？
注意：这是我第一次使用StackOverflow，所以如果我错过了任何事情，请告诉我。
码：
public class DaoTextImpl implements DAOInterface {
static final char DELIMITER=',';
@Override
public Repository load(String filename) {
Repository repository = new Repository();
try (BufferedReader br = new BufferedReader(new FileReader(filename))) {
String[] temp;
String line;
ArrayList<String> lines = new ArrayList<>();
ArrayList<YearData> yearData = new ArrayList<>();
while ((line = br.readLine()) != null){
lines.add(line);
}
for (int i = 0; i < lines.size(); i++) {
temp = lines.get(i).split(Character.toString(DELIMITER));
if (temp.length == 4) {
int id = Integer.valueOf(temp[0]);
String cityName = stripQuotes(temp[1]);
String country = stripQuotes(temp[2]);
int noofyeardata = Integer.valueOf(3);
for (int j = (i + 1); j < (i + noofyeardata); j++) {
String[] yearDataArray = lines.get(j).split(Character.toString(DELIMITER));
String year = stripQuotes(yearDataArray[0]);
float precipitation = Float.valueOf(yearDataArray[1]);
int maxtemp = Integer.valueOf(yearDataArray[2]);
int mintemp = Integer.valueOf(yearDataArray[3]);
int windspeed = Integer.valueOf(yearDataArray[4]);
String winddirection = stripQuotes(yearDataArray[5]);
yearData.add(new YearData(year, precipitation, maxtemp, mintemp, windspeed, winddirection));
}
repository.add(new City(id, cityName, country, yearData));
}
}
} catch (IOException ex) {
ex.printStackTrace();
}
return repository;
}
文本文件内容：
1,"Cartagena","Spain",3
"2015",0.2,33,26,6,"S"
"2016",0.0,33,24,8,"SSW"
"2017",0.0,32,25,6,"E"
2,"Glasgow","Scotland",3
"2015",0.0,19,8,3,"SE"
"2016",0.1,21,11,6,"SE"
"2017",2.1,19,11,9,"SW"
3,"Valencia","Spain",4
"2015",0.0,34,24,6,"SE"
"2016",0.0,39,23,5,"SSE"
"2017",0.0,32,24,5,"E"
"2014",0.0,29,20,6,"ESE"
最佳答案
您的代码中有几个问题。
1）在条件检查中您一人离开j < (i + noofyeardata)必须为j <= (i + noofyeardata)
2）int noofyeardata = Integer.valueOf(3)必须为int noofyeardata = Integer.valueOf(temp[3])。这就是为什么您总是将noofyeardata读为3的原因
还有一个一般点1。完成内部循环后，无需从上次中断的地方继续进行外部循环（i计数器）。您可以在for循环体内添加i（noofyeardata）i = i + noofyeardata + 1（因为您已经处理了noofyeardata行）。这样，您还可以删除if（temp.length == 4）检查。
for (int i = 0; i < lines.size();) {
temp = lines.get(i).split(Character.toString(DELIMITER));
int id = Integer.valueOf(temp[0]);
String cityName = stripQuotes(temp[1]);
String country = stripQuotes(temp[2]);
int noofyeardata = Integer.valueOf(temp[3]);
for (int j = (i + 1); j <= (i + noofyeardata); j++) {
//your existing code
}
repository.add(new City(id, cityName, country, yearData));
i += noofyeardata + 1;
}
}
1这是假设文件的内容严格遵循您提到的数据格式。
<id>, <cityName>, <country>, <noofyeardata1>
<noofyeardata1 rows>
<id>, <cityName>, <country>, <noofyeardata2>
<noofyeardata2 rows>
....
关于java - 为什么我的DAO读取.txt文件而不存储所有数据行？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/53484554/