Question

我有一个应该提供程序路径的类。为此，它确定Windows下的本地和漫游数据路径，并在Linux下获取home的子目录。除此之外，它提供了从其他路径派生的路径。

写

是否安全

public class DataDirectory {
    public static final File ROAMING;
    public static final File LOCAL;

    static {
        // set ROAMING and LOCAL
    }

    public static final File PROFILE =  doMkdirs(new File(ROAMING, "profiles");
    public static final File SETUP =  doMkdirs(new File(ROAMING, "setup");
    public static final File LOGFILES =  doMkdirs(new File(ROAMING, "logfiles");

    private static File doMkdirs(File file) {
        file.mkdirs();
        return file;
    }
}

或者我必须这样做

public class DataDirectory {
    public static final File ROAMING;
    public static final File LOCAL;

    public static final File PROFILE;
    public static final File SETUP;
    public static final File LOGFILES;

    static {
        // set ROAMING and LOCAL

        PROFILE = mkdirsRoaming("profiles");
        SETUP = mkdirsRoaming("setup");
        LOGFILES = mkdirsRoaming("logfiles");
    }

    public static final File PROFILE = doMkdirs(new File(ROAMING, "profiles");
    public static final File SETUP = doMkdirs(new File(ROAMING, "setup");
    public static final File LOGFILES = doMkdirs(new File(ROAMING, "logfiles");

    private static File doMkdirs(File file) {
        file.mkdirs();
        return file;
    }
}

为了安全起见？

Answer 1

我自己以QA风格回答这个问题。

java规范声明the initializers are executed in textual order, as though they were a single block。

这意味着第一个版本是安全的; static { }块之后的初始值设定项可以使用该块内设置的最终变量。

类中静态初始值设定项的初始化顺序

1 个答案: