在Xcode 11.3中读取文档中的文件失败

Question

当我使用URL的内容字符串读取文档中的文件时，它失败了

这是Xcode控制台中的错误：

错误域=NSCocoaErrorDomain Code=256"无法打开文件"1.txt"。"用户信息={NSURL=/var/mobile/Containers/Data/Application/E026973D-11B6-4895-B8FE-7F9FBCC11C12/Documents/bbbb/1.txt}

这是我的代码：

 //use objective-c
 +(NSString * )loadDataFromDocumentDirectory:(NSString *)path andSubDirectory:(NSString *)subdirectory {
    path = [self stripSlashIfNeeded:path];
    subdirectory = [self stripSlashIfNeeded:subdirectory];

    // Create generic beginning to file save path
    NSMutableString *savePath = [[NSMutableString alloc] initWithFormat:@"%@/",[self applicationDocumentsDirectory].path];
    [savePath appendString:subdirectory];
    [savePath appendString:@"/"];

    // Add requested save path
    NSError *err = nil;
    [savePath appendString:path];
    NSURL *fileURL = [NSURL URLWithString:savePath];
    NSString *loadStr = [NSString stringWithContentsOfURL:fileURL encoding:NSUTF8StringEncoding error:&err]  ;
    if (err) NSLog(@"load error : %@", err);

    return loadStr;
}

//use swift
let loadData = FileSave.loadData(fromDocumentDirectory: "1.txt", andSubDirectory: "bbbb")

Answer 1

您使用了错误的API：

URLWithString用于URL，包括必须使用的文件系统路径的方案（文件：///code>或https:///code>）。

但是，强烈建议始终使用与URL相关的API来构建路径

+ (NSString * )loadDataFromDocumentDirectory:(NSString *)path andSubDirectory:(NSString *)subdirectory {
    // path = [self stripSlashIfNeeded:path]; not needed
    // subdirectory = [self stripSlashIfNeeded:subdirectory]; not needed
    // Create generic beginning to file save path
    NSURL *saveURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:subdirectory];

    // Add requested save path
    NSError *err = nil;
    NSURL *fileURL = [saveURL URLByAppendingPathComponent:path];
    NSString *loadStr = [NSString stringWithContentsOfURL:fileURL encoding:NSUTF8StringEncoding error:&err]  ;
    if (err) NSLog(@"load error : %@", err);

    return loadStr;
}