IOS检测指定路径的文件是否存在

- (nsstring *)datapath:(nsstring *)file 
{ 
    nsstring *path = [[nshomedirectory() stringbyappendingpathcomponent:@"documents"] stringbyappendingpathcomponent:@"badge"]; 
    bool bo = [[nsfilemanager defaultmanager] createdirectoryatpath:path withintermediatedirectories:yes attributes:nil error:nil]; 
    nsassert(bo,@"创建目录失败"); 
    nsstring *result = [path stringbyappendingpathcomponent:file]; 
    return result; 
}  
- (void)viewdidload 
{ 
    [super viewdidload];  
    //此处首先指定了图片存取路径（默认写到应用程序沙盒 中） 
    nsarray *paths = nssearchpathfordirectoriesindomains(nsdocumentdirectory,nsuserdomainmask, yes); 
    //并给文件起个文件名 
    nsstring *imagedir = [[[paths objectatindex:0] stringbyappendingpathcomponent:@"163"] stringbyappendingpathcomponent:@"songzi"]; 
    //存放图片的文件夹 
    nsstring *imagepath =[imagedir stringbyappendingpathcomponent:@"文件名.png"]; 
    nsdata *data = nil; 
    //检查图片是否已经保存到本地 
    if([self isexistsfile:imagepath]){ 
        data=[nsdata datawithcontentsoffile:imagepath]; 
    }else{ 
        data = [nsdata datawithcontentsofurl:[nsurl urlwithstring: @"网址"]]; 
        //创建文件夹路径 
        [[nsfilemanager defaultmanager] createdirectoryatpath:imagedir withintermediatedirectories:yes attributes:nil error:nil]; 
        //创建图片 
        [uiimagepngrepresentation([uiimage imagewithdata:data]) writetofile:imagepath atomically:yes];          
    } 
    imageview.image = [uiimage imagewithdata:data]; 
} 

检查文件是否存在

nsstring *path = [[nsbundle mainbundle] pathforresource:filename oftype:@""];
if(path==null)

方法二：

nsfilemanager *filemanager = [nsfilemanager defaultmanager];
   //get documents directory
   nsarray *directorypaths = nssearchpathfordirectoriesindomains
   (nsdocumentdirectory, nsuserdomainmask, yes);
   nsstring *documentsdirectorypath = [directorypaths objectatindex:0];
   if ([filemanager fileexistsatpath:@""]==yes) {
        nslog(@"file exists");
    }  

方法三：

//判断文件是否存在
    if(![c judgefileexist:@"user.plist"])      
    {
        nslog(@"请确认该文件是否存在！");
        return;
    }

方法四：

//判断文件是否存在
-(bool)judgefileexist:(nsstring * )filename
{
    //获取文件路径
    nsstring *path = [[nsbundle mainbundle] pathforresource:filename oftype:@""];
    if(path==null)
        return no;
    returnyes;
}