Question

我需要将CSV文件中的元素分配到arraylist中。 CSV文件包含扩展名为.tar的文件名。在将其读入数组列表或修剪整个arraylist之前，我需要修剪这些元素。请帮帮我

try
   {
    String strFile1 = "D:\\Ramakanth\\PT2573\\target.csv";  //csv file containing data
    BufferedReader br1 = new BufferedReader( new FileReader(strFile1)); //create BufferedReader 
    String strLine1 = "";
    StringTokenizer st1 = null;

    while( (strLine1 = br1.readLine()) != null) //read comma separated file line by line
    {
     st1 = new StringTokenizer(strLine1, ","); //break comma separated line using ","

     while(st1.hasMoreTokens())
     {
      array1.add(st1.nextToken()); //store csv values in array
     }
    }
   }
   catch(Exception e)
   {
    System.out.println("Exception while reading csv file: " + e);                  
   }

Answer 1

如果你想删除＆＃34; .tar＆＃34;来自你的代币的字符串，你可以使用：

String nextToken = st1.nextToken();
if (nextToken.endsWith(".tar")) {
    nextToken = nextToken.replace(".tar", "");
}
array1.add(nextToken);

Answer 2

你不应该使用StringTokenizer JavaDoc说（部分） StringTokenizer是一个遗留类，出于兼容性原因而保留，尽管在新代码中不鼓励使用它。建议所有寻求此功能的人使用split String方法或java.util.regex包。您应关闭BufferedReader。您可以使用try-with-resources statement来执行此操作。并且，您可以使用for-each loop来迭代由String.split(String)生成的数组，下面的正则表达式可选地匹配,之前或之后的空格，如果是continue，您可以token循环String strFile1 = "D:\\Ramakanth\\PT2573\\target.csv"; try (BufferedReader br1 = new BufferedReader(new FileReader(strFile1))) { String strLine1 = ""; while( (strLine1 = br1.readLine()) != null) { String[] parts = strLine1.split("\\s*,\\s*"); for (String token : parts) { if (token.endsWith(".tar")) continue; // <-- don't add "tar" files. array1.add(token); } } } catch(Exception e) { System.out.println("Exception while reading csv file: " + e); }结束＆＃34; .tar＆＃34;喜欢

{{1}}

Answer 3

while(st1.hasMoreTokens())
{
    String input = st1.nextToken();
    int index = input.indexOf(".");  // Get the position of '.'

    if(index >= 0){     // To avoid StringIndexOutOfBoundsException, when there is no match with '.' then the index position set to -1.
        array1.add(input.substring(0, index)); // Get the String before '.' position.
    }
}

Answer 4

if(str.indexOf(".tar") >0)
str = str.subString(0, str.indexOf(".tar")-1);

如何在将元素分配到数组列表之前修剪元素？

4 个答案: