IOS关于String转UTF8（Unicode）

在iOS程序访问HTTP资源时需要对URL进行Encode

1.转换为UTF8（ios7 之后的方法）

NSString*charactersToEscape =@"我的生活";

NSCharacterSet*allowedCharacters = [[NSCharacterSet characterSetWithCharactersInString:charactersToEscape] invertedSet];

NSString*netStr1 = [charactersToEscape stringByAddingPercentEncodingWithAllowedCharacters:allowedCharacters];

转换之后的结果为

%E6%88%91%E7%9A%84%E7%94%9F%E6%B4%BB

2.转换为Unicode

-(NSString*) utf8ToUnicode:(NSString*)string

{

NSUIntegerlength = [stringlength];

NSMutableString*s = [NSMutableStringstringWithCapacity:0];

for(inti =0;i < length; i++)

{

unichar_char = [stringcharacterAtIndex:i];

//判断是否为英文和数字

if(_char <='9'&& _char >='0')

{

[sappendFormat:@"%@",[stringsubstringWithRange:NSMakeRange(i,1)]];

}

elseif(_char >='a'&& _char <='z')

{

[sappendFormat:@"%@",[stringsubstringWithRange:NSMakeRange(i,1)]];

}

elseif(_char >='A'&& _char <='Z')

{

[sappendFormat:@"%@",[stringsubstringWithRange:NSMakeRange(i,1)]];

}

else

{

[sappendFormat:@"\\u%x",[stringcharacterAtIndex:i]];

}

}

returns;

}

转换“我的生活”的结果为

\u6211\u7684\u751F\u6D3B