交换IMP

    NSURL *url = [NSURL URLWithString:@"www.baidu.com"];
    NSURL *url1 = [NSURL URLWithString:@"www.baidu.com/中文"];
    NSLog(@"%@",url);
    NSLog(@"%@",url1);

2019-10-17 10:03:41.407613+0800 MSDemoDYZ[10905:2932928] www.baidu.com
2019-10-17 10:03:41.407685+0800 MSDemoDYZ[10905:2932928] (null)

• 建一个NSURL的分类，在load方法中交换IMP

#import "NSURL+DYZURL.h"
#import <objc/runtime.h>


@implementation NSURL (DYZURL)

+ (void)load {
    Method URLWithStr = class_getClassMethod(self, @selector(URLWithString:));
    Method DYZURLWithStr = class_getClassMethod(self, @selector(DYZ_URLWithString:));
    //交换?  SEL -- IMP
    method_exchangeImplementations(URLWithStr, DYZURLWithStr);
}

+ (instancetype)DYZ_URLWithString:(NSString *)URLString {
    //我也不知道如何通过一个字符串创建一个url！！！！
    NSURL *url = [NSURL DYZ_URLWithString:URLString];
    if (url == nil) {
        URLString = [URLString stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];
    }
    return [NSURL DYZ_URLWithString:URLString];
}


@end

2019-10-17 10:14:19.008203+0800 MSDemoDYZ[10943:2936864] www.baidu.com
2019-10-17 10:14:19.008289+0800 MSDemoDYZ[10943:2936864] www.baidu.com/%E4%B8%AD%E6%96%87