iOS 文件的读取和写入

//找到路径
+(NSString *)findDocumentPath
{
NSArray * paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString * path = [paths firstObject];
NSLog(@"path === %@",path);
return path;

}
//字符串写入
+(BOOL)writeStringValue
{
NSString * temp =[WriteAndRead readNsstringValue];
BOOL result = NO;
//    查看文件里面有没有内容 没有的话直接写入有就字符串拼接
if (temp.length>0) {
NSString * str = [NSString stringWithFormat:@"%@行尸走肉",temp];
//     类名调用
NSString * path= [WriteAndRead  findDocumentPath];
NSString * realpath = [NSString stringWithFormat:@"%@/hellow.txt",path];
//    错误信息
NSError * error = Nil;
result =  [str writeToFile:realpath atomically:YES encoding:NSUTF8StringEncoding error:&error];
}
else{
NSString * str = @"横尸遍野";
//     类名调用
NSString * path= [WriteAndRead  findDocumentPath];
NSString * realpath = [NSString stringWithFormat:@"%@/hellow.txt",path];
//    错误信息
NSError * error = Nil;
result =  [str writeToFile:realpath atomically:YES encoding:NSUTF8StringEncoding error:&error];
}

//    取地址呦 指向指针的指针 双**
return result;
}
//数组写入
+(BOOL)writeArrayValue
{
NSArray * arr = [[NSArray alloc] initWithObjects:@"1",@"2",@"3", nil nil];
NSString * path = [WriteAndRead findDocumentPath];
NSString * realpath = [NSString stringWithFormat:@"%@/arr.txt",path];

BOOL result =  [arr writeToFile:realpath atomically:YES];
return result;

}
//数据data写入
+(BOOL)writeDataValue
{
NSString * str = [NSString stringWithFormat:@"来自星星的xx"];
NSData * data = [str dataUsingEncoding:NSUTF8StringEncoding];
NSString * path = [WriteAndRead findDocumentPath];
NSString * realpath = [NSString stringWithFormat:@"%@/data.txt",path];
BOOL result = [data writeToFile:realpath atomically:YES];
return result;

}  <span style="font-size:18px;">
</span>

//读取字符串
+(NSString * )readNsstringValue
{
NSString * path  =[WriteAndRead findDocumentPath];
NSString * realpath = [NSString stringWithFormat:@"%@/hellow.txt",path];
NSString * value = [[NSString alloc] initWithContentsOfFile:realpath encoding:NSUTF8StringEncoding error:NULL];
return [value autorelease];
//    加号方法就不用autorelease

}
// 数组的读取
+(NSArray *)readArrayValue
{
NSString * path = [WriteAndRead findDocumentPath];
NSString * realpath = [NSString stringWithFormat:@"%@/arr.txt",path];
NSArray * value = [NSArray arrayWithContentsOfFile:realpath];
return value;

}
// data的读取
+(NSData*)readDataValue
{
NSString * path = [WriteAndRead findDocumentPath];
NSString * realpath = [NSString stringWithFormat:@"%@/data.txt",path];
NSData * value = [NSData dataWithContentsOfFile:realpath];
return value;

}