ios 如何将 NSString 值转换为 NSData？

How do I convert an NSString value to NSData?

提问by flitzwald

How do I convert an NSStringvalue to NSData?

如何将NSString值转换为NSData？

回答by flitzwald

NSString* str = @"teststring";
NSData* data = [str dataUsingEncoding:NSUTF8StringEncoding];

回答by ALOK KUMAR

NSString *str = @"helowrld";
// This converts the string to an NSData object
NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding];

you can take reference from this link

你可以参考这个链接

回答by Andrew Kolesnikov

Do:

做：

NSData *data = [yourString dataUsingEncoding:NSUTF8StringEncoding];

then feel free to proceed with NSJSONSerialization:JSONObjectWithData.

然后随意继续NSJSONSerialization:JSONObjectWithData。

---

---

Correction to the answer regarding the NULL terminator

更正有关 NULL 终止符的答案

Following the comments, official documentation, and verifications, this answer was updated regarding the removal of an alleged NULL terminator:

根据评论、官方文档和验证，此答案已更新，删除了所谓的 NULL 终止符：

1. As documented by dataUsingEncoding::

   Return Value

   The result of invoking dataUsingEncoding:allowLossyConversion:with NO as the second argument

2. As documented by getCString:maxLength:encoding:and cStringUsingEncoding::

   note that the data returned by dataUsingEncoding:allowLossyConversion:is not a strict C-string since it does not have a NULL terminator

1. 正如dataUsingEncoding所记录的：

   返回值

   dataUsingEncoding:allowLossyConversion:以 NO 作为第二个参数的调用结果

2. 正如getCString:maxLength:encoding:和cStringUsingEncoding: 所记录的：

   请注意，返回的数据dataUsingEncoding:allowLossyConversion:不是严格的 C 字符串，因为它没有 NULL 终止符

回答by Sruit A.Suk

In case of Swift Developer coming here,

如果 Swift 开发人员来到这里，

to convert from NSString / String to NSData

从 NSString / String 转换为 NSData

var _nsdata = _nsstring.dataUsingEncoding(NSUTF8StringEncoding)

回答by Shamsiddin

Objective-C:

目标-C：

NSString *str = @"test string";
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:str];
NSString *thatStr = [NSKeyedUnarchiver unarchiveObjectWithData:data];

Swift:

迅速：

let str = "test string"
let data = NSKeyedArchiver.archivedData(withRootObject: str)
let thatStr = NSKeyedUnarchiver.unarchiveObject(with: data) as! String

回答by Jerry Thomsan

First off, you should use dataUsingEncoding:instead of going through UTF8String. You only use UTF8Stringwhen you need a Cstring in that encoding.

首先，您应该使用dataUsingEncoding:而不是通过UTF8String. 只有UTF8String在需要C该编码的字符串时才使用。

Then, for UTF-16, just pass NSUnicodeStringEncodinginstead of NSUTF8StringEncodingin your dataUsingEncoding:message.

然后，对于UTF-16，只需传递NSUnicodeStringEncoding而不是NSUTF8StringEncoding在您的dataUsingEncoding:消息中。

回答by Hymans205

For Swift 3, you will mostly be converting from Stringto Data.

对于斯威夫特3，您将主要从转换String到Data。

let myString = "test"
let myData = myString.data(using: .utf8)
print(myData) // Optional(Data)

回答by Nex Mishra

NSString *str = @"hello";
NSData *data = [NSData dataWithBytes:str.UTF8String length:str.length];

回答by Nick

Objective-C:

目标-C：

NSString to NSData:

NSString 到 NSData：

NSString* str= @"string";
NSData* data=[str dataUsingEncoding:NSUTF8StringEncoding];

NSData to NSString:

NSData 到 NSString：

NSString* newStr = [[NSString alloc] initWithData:theData encoding:NSUTF8StringEncoding];

Swift:

迅速：

String to Data:

字符串到数据：

var testString = "string"
var somedata = testString.data(using: String.Encoding.utf8)

Data to String:

数据到字符串：

var backToString = String(data: somedata!, encoding: String.Encoding.utf8) as String!

回答by Kamani Jasmin

NSString *str = @"Banana";
NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:true];