Objective-C封装字符串存储操作示例

objective-c简单封装 字符串的存储操作，省去中间沙盒处理方式

/存储publickey和sessionid -- writecontent： nil － 仅取出数据， 其他 － 修改原内容并提取
+(nsstring *)storefile:(nsstring *)filename content:(nsstring *)writecontent
{
    nsstring *pathdocuments=[nssearchpathfordirectoriesindomains(nsdocumentdirectory, nsuserdomainmask, yes) objectatindex:0];

    nsstring *createpath=[nsstring stringwithformat:@"%@/%@",pathdocuments,filename];//用文件名补全路径
    nserror *readfileerror;
    nsstring *readcontent ;
    nsdata *data ;
    if ([[nsfilemanager defaultmanager] fileexistsatpath:createpath])//判断文件是否已存在
    {
        if (nil == writecontent) {
            readcontent = [nsstring stringwithcontentsoffile:createpath encoding:nsutf8stringencoding error:&readfileerror;];
        }else{
            data = [writecontent datausingencoding:nsutf8stringencoding];//新文件的初始数据
            [[nsfilemanager defaultmanager] createfileatpath:createpath contents:data attributes:nil];//创建文件
            readcontent = [nsstring stringwithcontentsoffile:createpath encoding:nsutf8stringencoding error:&readfileerror;];           
        }
    }
    else
    {
        if (nil == writecontent) {
            return nil;
        }else{
            data = [writecontent datausingencoding:nsutf8stringencoding];//新文件的初始数据
            [[nsfilemanager defaultmanager] createfileatpath:createpath contents:data attributes:nil];//创建文件
            readcontent = [nsstring stringwithcontentsoffile:createpath encoding:nsutf8stringencoding error:&readfileerror;];
        }
    }
    return readcontent;
}

+ ( nsarray * )storearryfile:(nsstring *)filename content:( nsarray *)writearry
{
    //步骤
    //存 ：将 数组放入 字典
    //取： 从字典取出数组
    if ( writearry == nil)//读取文件
    {
        nsstring *storestr = [fnprorequest storefile:filename content:nil];
        nsdictionary *dic = (nsdictionary *)[storestr jsonvalue];

        nslog(@"%@", dic);

        return (nsarray *)[dic objectforkey:filename];
    }
    else
    {
        nsarray *objectsarry = [[nsarray alloc]initwithobjects:writearry,nil ];
        nsarray *keysarry    = [[nsarray alloc]initwithobjects:filename,nil ];
        nsdictionary *dic = [[nsdictionary alloc]initwithobjects:objectsarry forkeys:keysarry];
        nsstring *storestr = [dic jsonrepresentation];
        [self storefile:filename content:storestr];
        [objectsarry release];
        [keysarry release];
        [dic release];
    }
    return nil;
}