. lang。ClassCastException:. lang。字符串不能被转换为java.lang.Long

I created this simple example which is used to read Linux uptime:

我创建了这个简单的示例，用于读取Linux运行时:

public String getMachineUptime() throws IOException {
    String[] dic = readData().split(" ");

    long s = (long) Array.get(dic, 1);
    return calculateTime(s);
}

private String readData() throws IOException {
    byte[] fileBytes;
    File myFile = new File("/proc/uptime");
    if (myFile.exists()) {
        try {
            fileBytes = Files.readAllBytes(myFile.toPath());
        } catch (java.nio.file.AccessDeniedException e) {
            return null;
        }

        if (fileBytes.length > 0) {
            return new String(fileBytes);
        }
    }
    return null;
}

private String calculateTime(long seconds) {
    int day = (int) TimeUnit.SECONDS.toDays(seconds);
    long hours = TimeUnit.SECONDS.toHours(seconds)
            - TimeUnit.DAYS.toHours(day);
    long minute = TimeUnit.SECONDS.toMinutes(seconds)
            - TimeUnit.DAYS.toMinutes(day)
            - TimeUnit.HOURS.toMinutes(hours);
    long second = TimeUnit.SECONDS.toSeconds(seconds)
            - TimeUnit.DAYS.toSeconds(day)
            - TimeUnit.HOURS.toSeconds(hours)
            - TimeUnit.MINUTES.toSeconds(minute);

    return "Day " + day + " Hour " + hours + " Minute " + minute
            + " Seconds " + second;
}

When I run the code I get this exception:

当我运行代码时，我得到这个异常:

java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Long

. lang。ClassCastException:. lang。字符串不能被转换为java.lang.Long

Is there any other way to convert the result?

有没有其他方法来转换结果?

2 个解决方案

#1

I believe you have to replace

我认为你必须替换

long s = (long) Array.get(dic, 1);

with

与

long s = Long.valueOf((String) Array.get(dic, 1));

or even better:

或者更好的是:

long s = Long.valueOf(dic[1]);

The reason is that your array consists of String object, and direct casting won't work.

原因是您的数组由String对象组成，而直接强制转换将不起作用。

#2

The problem appears to be in the following line:

问题似乎如下:

long s = (long) Array.get(dic, 1);

The get(Object array, int index) method of java.lang.reflect.Array returns an instance of Object, which cannot be directly cast to long.

java.lang. reflection的get(Object array, int index)方法。数组返回一个对象实例，该对象不能直接转换为long。
You can access the element of the array simply by dic[1] instead of Array.get(dic, 1)

您可以通过dic[1]而不是数组访问数组的元素。get(dic,1)

Replace with the following code:

替换为以下代码:

long s = Long.parseLong(dic[1]);

#1