NSString

来源：互联网发布：淘宝上二手手机良心店编辑：程序博客网时间：2024/06/17 01:41

创建常量字符串
NSString *string = @”This is a String”;//不足要释放内粗
创建空字符串，然后赋值
NSString * string = [[NSString alloc] init];
string = @”This is a String”;
通过字符串创建字符串
[[NSString alloc] initWithString:@”This is a String”];
[NSString stringWithString:@”This is a Strng”]; //不需要管理内存
或者
[[NSString alloc] initWithFormat:@”My age is %i”, 17];
用C标准创建字符串
char *s = “This is a String”;
[[NSString alloc] initWithCString:cString encoding:NSUTF8StringEncoding];
或者：
[[NSString alloc] initWithUTF8String:cstring];
对应：
[NSString stringWithUTF8String:”This is a Sting”];
区别在于下面不需要管理内存
从文件中读取字符串
NSString *path = /Users/apple/a.txt;
NSString *str1 = [NSString stringWithContentsOfFile:path]; //不能解析中文，过期方法
或：

NSSerror *error = nil; //记录错误信息NSString *path = @"/User/apple/a.txt";NSString *string = [[NSString alloc]initWithContentsOfFile:path encoding:NSUTF8StringEncoding error:&error];if (error) {    NSString *desc = [error localizedDescription];    NSSLog(@"文件读取失败：%@", desc);} else {    NSLog(@"文件读取成功：%@"， string);}// 将中文字符编码转换为NSStringEncoding格式的编码NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding（kCFStringEncodingGB_18030_2000）；

URL读取本地文件

NSURL *url = [NSURL URLWithString:@"file:///User/apple/a.txt"];NSString *str2 = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncodeing error:nil];

URL读取远程文本

NSURL *url = [NSURL URLWithString:@"http://www.baidu.com"];NSString *str3 = [NSString stringWithContensOfURL:url encoding:NSUTF8StringEncodeing error:nil];

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