Question

我在文件中有很多次的列表。我的目标是将所有时间始终放在自己的字符串数组中，称为time1，time2和time3。该文件如下所示：

time1, 5:01,3:21,4:05,1:52 time2, 2:11,6:35,2:00,5:00 time3, 12:09, 
11:35, 9:02

我已尝试将读取的每一行拆分，然后将其转换为令牌，并以逗号分隔。但是，当前这似乎不是一个有效的解决方案，因为第一个元素始终以空格开头，而最后一个元素没有逗号。我想知道是否有人知道解决此问题的方法。

这是到目前为止我想出的代码：

public void read_file(){
try{
    times = new Scanner(new File("times.csv"));
    read_file();
}
catch(Exception e){
    System.out.printf("Could not find file\n");
}                
}
public void read_file(){

while(times.hasNextLine()){
    i++;
    String a = times.nextLine();
    String time[] = a.split(",");
    //would only add first 4 elements
    if(i < 4){
        timeList1.add(time[i])
    }
}
}

这里的问题是我不知道如何检查要继续运行的元素数，因为列表中的时间是不可预测的。唯一不变的是，将始终有3个时间列表，分别称为time1，time2和time3。

Answer 1

这是一个可以完成您想要的单元测试。我不得不格式化您的输入字符串。您应该能够以最小的更改为您完成这项工作。

import org.junit.Test;

import java.time.LocalDate;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author Dr. Parameter
 */
public class TimeParser {

    private final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("k:mm");

    @Test
    public void test(){

        // Test input
        String times = "time1, 5:01,3:21,4:05,1:52, time2, 2:11,6:35,2:00,5:00, time3, 12:09,11:35, 9:02";

        // Set up Objects used to collect
        String currentKey = "";
        HashMap<String, List<LocalTime>> timeMap = new HashMap();

        // Iterate though list
        String[] lineBreaks = times.split("\n");
        for(String line : lineBreaks){
            String[] csvBreaks = line.split(",");
            for(String csv : csvBreaks){

                //try to parse a time and add it to the key set, add a new key if there is a failure
                try {
                    timeMap.get(currentKey).add(LocalTime.parse(csv.trim(), formatter));
                } catch (Exception ex){
                    currentKey = csv;
                    timeMap.put(currentKey, new ArrayList<>());
                }
            }
        }

        //Print result:
        for(Map.Entry<String, List<LocalTime>> entry : timeMap.entrySet()){
            System.out.println("times for key: " + entry.getKey());
            for(LocalTime time : entry.getValue()){
                System.out.println("\t" + time);
            }
        }
    }
}

Answer 2

这是另一种更简单的方法：

public class ReadTimes {
    private Map<String, List<String>> timeLists = new HashMap();
    public void read_file() {
        try {
            Scanner times = new Scanner(new File("times.csv"));
            read_file(times);
        } catch (Exception e) {
            System.out.printf("Could not find file\n");
        }
    }
    public void read_file(Scanner times) {
        String label=null;
        while (times.hasNextLine()) {
            String time[] = times.nextLine().trim().split("[, ]+");
            for (String timeString : time) {
                if (timeString.startsWith("time")) {
                    label = timeString;
                    timeLists.put(label, new ArrayList());
                } else if (label != null) {
                    timeLists.get(label).add(timeString);
                }
            }
        }
        // dump the map of arraylists for demonstration purposes...
        for (Entry<String,List<String>> timeEntry : timeLists.entrySet()) {
            System.out.println(timeEntry);
        }
    }

    public static void main(String[] args) {
        ReadTimes rt = new ReadTimes();
        rt.read_file();
    }
}

鉴于问题中显示的输入数据，将产生以下输出：

time1=[5:01, 3:21, 4:05, 1:52]
time2=[2:11, 6:35, 2:00, 5:00]
time3=[12:09, 11:35, 9:02]

Answer 3

由于您确定要精确地使用3个字符串数组，因此下面的代码以“ time”为分隔符来分割初始字符串，并删除了"1, "，"2, "，"3, "首先，修剪并删除,，最后删除所有空格后，以,为分隔符将每个项目分割成3个字符串数组。

    String times = "time1, 5:01,3:21,4:05,1:52, time2, 2:11,6:35,2:00,5:00, time3, 12:09,11:35, 9:02";

    String[] splitted = times.split("time");

    // exclude 0th item which is ""
    for (int i = 1; i < splitted.length; i++) {
        splitted[i] = splitted[i].trim();

        int index = splitted[i].indexOf(" ");

        if (splitted[i].endsWith(","))
            splitted[i] = splitted[i].substring(index + 1, splitted[i].length() - 1);
        else
            splitted[i] = splitted[i].substring(index + 1);

        splitted[i] = splitted[i].replaceAll(" ", "");
    }

    try {  // just in case
        String time1[] = splitted[1].split(",");
        System.out.println(Arrays.toString(time1));
        String time2[] = splitted[2].split(",");
        System.out.println(Arrays.toString(time2));
        String time3[] = splitted[3].split(",");
        System.out.println(Arrays.toString(time3));
    } catch (Exception e) {
        e.printStackTrace();
    }

打印3个字符串数组：

[5:01, 3:21, 4:05, 1:52]
[2:11, 6:35, 2:00, 5:00]
[12:09, 11:35, 9:02]

从Java中用逗号和标题分隔的文件中读取时间

3 个答案: