在项目逐渐成熟之后，需要app升级之后执行一些特定的操作，比如删除之前的无用缓存或更新一些配置等。

项目中可使用runtime+category来实现此操作

启动后检查升级类 XXAppUpdater

//启动后执行方法
[XXAppUpdater updateToVersion]；

XXAppUpdater 具体实现

static NSArray* getVersionByStr(NSString *strVersion) {
    NSArray *versionStrArr = [strVersion componentsSeparatedByString:@"."];
    NSMutableArray *version = [NSMutableArray arrayWithCapacity:versionStrArr.count];
    for (int i = 0; i < [versionStrArr count]; i++) {
        NSString *str = [versionStrArr objectAtIndex:i];
        [version addObject:[NSNumber numberWithInt:[str intValue]]];
    }
    return version;
}

static NSArray* getVersionByMethodName(NSString *methodName) {
    NSError *error = NULL;
    NSArray *arrRegex = @[@"appUpgradeTo_(\\d+)_(\\d+)_(\\d+)",
                      @"appUpgradeTo_(\\d+)_(\\d+)"];
    for (NSString *regexStr in arrRegex) {
        NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:regexStr
                                                                       options:NSRegularExpressionCaseInsensitive
                                                                             error:&error];
    
        NSTextCheckingResult *match = [regex firstMatchInString:methodName
                                                    options:0
                                                      range:NSMakeRange(0, [methodName length])];
        if (match) {
            const NSUInteger count = match.numberOfRanges;
            NSMutableArray *version = [NSMutableArray arrayWithCapacity:count];
            for (int i = 1; i < count; i++) {
                NSString *str = [methodName substringWithRange:[match rangeAtIndex:i]];
                [version addObject:[NSNumber numberWithInt:[str intValue]]];
            }
            return version;
        }
    }
    return nil;
}

static NSInteger compareVersion(NSArray *ver1, NSArray *ver2) {
    const NSInteger count = MIN(ver1.count, ver2.count);
    for (int i = 0; i < count; i++) {
        NSNumber *left = [ver1 objectAtIndex:i];
        NSNumber *right = [ver2 objectAtIndex:i];
        if (left.intValue > right.intValue) {
            return 1;
        }
        if (left.intValue < right.intValue) {
            return -1;
        }
     }
    if (ver1.count > ver2.count) {
        return 1;
    } else if (ver1.count < ver2.count) {
        return -1;
    } else {
        return 0;
    }
 }
+ (void)updateToVersion {
    unsigned int count;
    //runtime 获取该类的所有方法   
    Method* methods = class_copyMethodList(object_getClass([XXAppUpdater class]), &count);
    if (count == 0) {
        [WJUserDefaults updateAppVersion];
        return;
    }
    //有值的话去创建数组得到方法名
    NSMutableArray* methodArray = [NSMutableArray arrayWithCapacity:count];
    for (int i = 0; i < count; i++)
    {
        SEL selector = method_getName(methods[i]);
        const char* methodName = sel_getName(selector);
        [methodArray addObject:[NSString  stringWithCString:methodName encoding:NSUTF8StringEncoding]];
    }
    free(methods);
    //获取目前的版本号
    NSString *version = [WJUserDefaults localAppVersion];
    NSPredicate *predicate = [NSPredicate predicateWithBlock:^BOOL(id evaluatedObject, NSDictionary *bindings) {
        NSArray *left = getVersionByStr(version);
        NSArray *right = getVersionByMethodName(evaluatedObject);
        if (right == nil) {
            return NO;
        }
        return compareVersion(left, right) < 0;
    }];
    //筛选出需要执行的方法
    NSArray *upgradeMethods = [methodArray filteredArrayUsingPredicate:predicate];
        WJUpdaterLog(@"upgradeMethods = %@", upgradeMethods);
        upgradeMethods = [upgradeMethods sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
        NSArray *left = getVersionByMethodName(obj1);
        NSArray *right = getVersionByMethodName(obj2);
        return compareVersion(left, right);
    }];
    //遍历去执行分类的升级后需要执行的方法
    for (NSString *methodName in upgradeMethods) {
        SEL upgrade = NSSelectorFromString(methodName);
        if (![[self class] performSelector:upgrade]) {
            WJUpdaterLog(@"%@ failed", methodName);
            break;
        } else {
            WJUpdaterLog(@"%@ succeed", methodName);
        }
    }
    [WJUserDefaults updateAppVersion];
}

每次升级需要更新的操作放在XXAppUpdater分类中即可

//添加分类方法
+ (BOOL)appUpgradeTo_8_8_8 {
 //升级后执行的操作

}