Predef.readLine行为

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class PredefExample {
   public static void main(String[] args) throws IOException {
      String fileName = "example.txt"; // 指定文件名
      int lineLength = 100; // 指定每行字符数

      BufferedReader reader = new BufferedReader(new FileReader(fileName));
      String line = reader.readLine();
      int count = 0;

      while (line != null && count < lineLength) {
         System.out.println(line);
         line = reader.readLine();
         count += line.length() + 1;
      }

      reader.close();
   }
}