#import <objc/runtime.h>

- (NSString *)description
{
    NSMutableDictionary *dictionary = [NSMutableDictionary dictionary];
    uint count;
    objc_property_t *properties = class_copyPropertyList([self class], &count);
    for (int i = 0; i < count; i++)
    {
        objc_property_t property = properties[i];
        NSString *name = @(property_getName(property));
        id value = [self valueForKey:name]?:@"nil";
        [dictionary setObject:value forKey:name];
    }
    
    free(properties);
    return [NSString stringWithFormat:@"<%@:%p> -- %@", [self class], self, dictionary];
    
}

很多时候，我们在断点调试的时候，并不是使用NSLog(@"%@",model);来打印模型，而是通过po这个命令,我们需要重写debugDescription方法而不是description方法

debugDescription方法只会在调试po的时候调用，而在代码中打印不会调用。但是我们需要在每个模型中都重写这个方法，而且代码都不一样，肯定受不了。我的解决方式是写一个NSObject的分类NSObject+DebugDescription并重写debugDescription，并处理了po其他类型的情况

#import "NSObject+DebugDescription.h"
#import <objc/runtime.h>

@implementation NSObject (DebugDescription)

- (NSString *)debugDescription
{
    if ([self isKindOfClass:[NSArray class]] || [self isKindOfClass:[NSDictionary class]] || [self isKindOfClass:[NSNumber class]] || [self isKindOfClass:[NSString class]])
    {
        return self.debugDescription;
    }
    NSMutableDictionary *dictionary = [NSMutableDictionary dictionary];
    uint count;
    objc_property_t *properties = class_copyPropertyList([self class], &count);
    for (int i = 0; i < count; i++)
    {
        objc_property_t property = properties[i];
        NSString *name = @(property_getName(property));
        id value = [self valueForKey:name]?:@"nil"; // 默认值为nil字符串
        [dictionary setObject:value forKey:name];
    }
    free(properties);
    return [NSString stringWithFormat:@"<%@: %p> -- %@", [self class], self, dictionary];
}

@end