Java ArrayList 和 FileReader

Question

我真的被这个问题困住了。我想知道是否可以在读取文件时排除 arraylist 中的所有元素？预先感谢您!

我的数组列表(排除列表)上有这样的元素:

test1
test2
test3

我的文件(readtest)上有 csv 数据，如下所示:

test1,off
test2,on
test3,off
test4,on

所以我期望的是在 while 循环中排除 arraylist 中的所有数据，然后输出如下:

test4,on

这是我的代码:

String exclude = "C:\\pathtomyexcludefile\\exclude.txt";    
String read = "C:\\pathtomytextfile\\test.txt";

                   File readtest = new File(read);
                   File excludetest = new File(exclude);

                    ArrayList<String> excludelist = new ArrayList();
                    excludelist.addAll(getFile(excludetest));

    try{
            String line;
                    LineIterator it = FileUtils.lineIterator(readtest,"UTF-8");
                    while(it.hasNext()){
            line = it.nextLine();
            //determine here

            }
    catch(Exception e){
        e.printStackTrace();
        }

    public static ArrayList<String> getFile(File file) {
            ArrayList<String> data = new ArrayList();
            String line;
              try{
                LineIterator it = FileUtils.lineIterator(file,"UTF-8");
                    while(it.hasNext()){
                        line = it.nextLine();
                        data.add(line);     
                 }
                    it.close();
              }

                          catch(Exception e){
                 e.printStackTrace();
              }
          return data;
        }

Answer 1

可能有更有效的方法来执行此操作，但您可以使用 String.startsWith 针对 excludeList 中的每个元素检查正在读取的每一行。如果该行不以要排除的单词开头，请将其添加到 approvedLines 列表中。

String exclude = "C:\\pathtomyexcludefile\\exclude.txt";    
String read = "C:\\pathtomytextfile\\test.txt";

File readtest = new File(read);
File excludetest = new File(exclude);

List<String> excludelist = new ArrayList<>();
excludelist.addAll(getFile(excludetest));
List<String> approvedLines = new ArrayList<>();

LineIterator it = FileUtils.lineIterator(readtest, "UTF-8");

while (it.hasNext()) {
    String line = it.nextLine();
    boolean lineIsValid = true;
    for (String excludedWord : excludelist) {
        if (line.startsWith(excludedWord)) {
            lineIsValid = false;
            break;
        }
    }
    if (lineIsValid) {
        approvedLines.add(line);
    }
}

// check that we got it right
for (String line : approvedLines) {
    System.out.println(line);
}