1.NSdata 转NSString:
[[NSString alloc] initWithData:(NSData *)data encoding:(NSStringEncoding) encoding;
e.g:读取text.plist文件存放的内容并转化为NSString类型
NSData *data = [[NSData alloc] initWithContentOfFile: @"text.plist"];
NSString *string =[[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding];
2. NSString转NSdata:
[NSString alloc] dataUsingEncoding:(NSStringEncoding) encoding;
e.g:
NSString *string = @"abc";
NSData *data = [string dataUsingEncoding: NSUTF8StringEncoding];