package onlyfun.caterpillar;
import java.io.*;
import java.util.*;
public class RandomAccessFileDemo {
public static void main(String[] args) {
Student[] students = {
new Student("Justin", 90),
new Student("momor", 95),
new Student("Bush", 88),
new Student("caterpillar", 84)};
try {
File file = new File(args[0]);
// 建立RandomAccessFile實例並以讀寫模式開啟檔案
RandomAccessFile randomAccessFile =
new RandomAccessFile(file, "rw");
for(int i = 0; i < students.length; i++) {
// 使用對應的write方法寫入資料
randomAccessFile.writeChars(students[i].getName());
randomAccessFile.writeInt(students[i].getScore());
}
Scanner scanner = new Scanner(System.in);
System.out.print("讀取第幾筆資料?");
int num = scanner.nextInt();
// 使用seek()方法操作存取位置
randomAccessFile.seek((num-1) * Student.size());
Student student = new Student();
// 使用對應的read方法讀出資料
student.setName(readName(randomAccessFile));
student.setScore(randomAccessFile.readInt());
System.out.println("姓名:" + student.getName());
System.out.println("分數:" + student.getScore());
// 設定關閉檔案
randomAccessFile.close();
}
catch(ArrayIndexOutOfBoundsException e) {
System.out.println("請指定檔案名稱");
}
catch(IOException e) {
e.printStackTrace();
}
}
private static String readName(
RandomAccessFile randomAccessfile)
throws IOException {
char[] name = new char[15];
for(int i = 0; i < name.length; i++)
name[i] = randomAccessfile.readChar();
// 將空字元取代為空白字元並傳回
return new String(name).replace('\0', ' ');
}
}