java - randomAccessFile 方法不写入或读取整数？

Question

我有两种方法，一种将 10 个整数写入 randomAccessFile，另一种读取这 10 个整数。我相信 writer 方法没有按预期运行。

这是我写入随机文件的方法:

try{
                RandomAccessFile file = new RandomAccessFile(nextPath, "rw");
                System.out.println("Writing these ints to file");
                file.seek(0);
                // here I loop 10 times and write the int at position i
                for (int i = 0; i < 10; i++)
                {
                    file.seek(i);
                    toAdd = randInt(1,10);
                    file.writeInt(toAdd);
                    System.out.printf(toAdd + " ");

                }
                file.seek(0);
                System.out.println("");
            }catch(IOException ex){
                System.out.println("Error");
                System.exit(0);}

这是我读取整数的方法:

public int[] readRandom()
    {
        System.out.println("Unsorted ints found in random file:");
        int[] randomInts = new int[10];
        try{        
                RandomAccessFile file = new RandomAccessFile(nextPath, "rw");
                file.seek(0);
                // here I loop 10 times, and read the Int at position i
                for(int i = 0; i < 10; i++)
                {
                    file.seek(i);
                    randomInts[i] = file.readInt();
                    System.out.printf(randomInts[i] + " ");


                }   
                file.seek(0);
                System.out.println("");
            }catch(IOException exc){
                System.out.println("Error reading ints");
                System.exit(0);}
                return randomInts;
            }

这是我的输出:为什么只读取最后一个 int？

Writing these ints to file
1 4 5 6 2 4 10 6 5 5 
Unsorted ints found in random file:
0 0 0 0 0 0 0 0 0 5

Answer 1

为什么使用RandomAccessFile来执行顺序写入和顺序读取？它违背了此类的目的。
此外，您不应该震惊捕获的异常，而应该记录或跟踪它们。

关于您的意外结果，它是由不需要的 seek() 调用引起的。您无需在每次读取或写入操作时调用 seek()，因为 readInt() 和 writeInt() 会使光标向前移动.

我简化了您的示例代码以强调重要部分:

public void write() {
    try {
        RandomAccessFile file = new RandomAccessFile("temp.txt", "rw");
        System.out.println("Writing these ints to file");
        file.seek(0);
        for (int i = 0; i < 10; i++) {              
            file.writeInt(i);
            System.out.printf(i + " ");
        }           
    } catch (IOException ex) {
        ex.printStackTrace();
        System.exit(0);
    }
}

public int[] readRandom() {
    System.out.println("Unsorted ints found in random file:");
    int[] randomInts = new int[10];
    try {
        RandomAccessFile file = new RandomAccessFile("temp.txt", "rw");
        long filePointer = file.getFilePointer();

        file.seek(0);
        for (int i=0; i<10; i++){
            randomInts[i] = file.readInt();
            System.out.printf(randomInts[i] + " ");
        }               
    } catch (IOException ex) {
        ex.printStackTrace();
        System.exit(0);
    }
    return randomInts;
}