程序正在从文本文件读取。文本文件的每一行均以-2到2之间的数字开头。数字之后是一个句子。请参阅下面的txt文件的前三行：
1 Campanella gets the tone just right -- funny in the middle of sad in the middle of hopeful .
-2 Nothing more than an amiable but unfocused bagatelle that plays like a loosely-connected string of acting-workshop exercises .
1 It 's a sharp movie about otherwise dull subjects .
我有一个名为placeholder的类，其中包含以下字段：
public class placeholder implements Comparable<placeholder> {
protected int score;
protected String text;
public placeholder(int score, String text) {
this.score = score;
this.text = text;
}
}
我希望一种名为readFile的方法逐行进行，并将每一行存储到名为reviewsDB的列表中。列表中的每个对象的类型均为placeholder，行首的编号为score值，随后的单词为text值。我可以在以下区域中输入什么代码，以使数字和文本之间的每一行分开？
public static List<placeholder> readFile(String filename) {
File movieReviews = new File("reviews.txt");
try {
Scanner scanner = new Scanner(movieReviews);
scanner.nextLine();
List<placeholder> reviewsDB = new ArrayList<placeholder>();
while (scanner.hasNextLine()) {
int sentenceScore = 0;
String sentenceText = null;
//code to separate the number and text in each line here
placeholder newSentence = new placeholder(sentenceScore, sentenceText);
reviewsDB.add(newSentence);
}
return reviewsDB;
}
catch (Exception e) {
System.out.println("Something went wrong");
return null;
}
}
您可以使用Files.readAllLines(Path, Charset)获取代表文件内容的字符串列表。然后，您可以遍历列表并使用String.split(Regex, Limit)将字符串分成几部分。然后，您可以从零件中创建一个新的Placeholder-Object。
参见：