NSMutableDictionary写文件失败解决

下列代码保存文件失败：

    NSString *plistPath = [[NSBundle mainBundle]pathForResource:@"JsEtag" ofType:@"plist"];

    NSMutableDictionary *dataDic = [[NSMutableDictionary alloc]initWithContentsOfFile:plistPath];

    dataDic[fileName] = Etag;

    BOOL flag =  [dataDic writeToFile:plistPathatomically:YES];

解决方法：

由于路径访问不对，应用使用NSSearchPathForDirectoriesInDomains获取路径，代码如下：

 NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

    NSString*documentsDirectory = [pathsobjectAtIndex:0];

    NSString  *plistPath = [documentsDirectorystringByAppendingPathComponent:@"JsEtag.plist"];

    NSMutableDictionary *dataDic = [[NSMutableDictionary alloc] initWithContentsOfFile: plistPath];

    if(!dataDic) {

        dataDic = [[NSMutableDictionaryalloc]init];

    }

    //保存Etag

    dataDic[fileName] = Etag;

    BOOLflag = [dataDicwriteToFile:plistPathatomically:YES];