使用runtime->json转model

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分享一个使用runtime进行json转model的方法, 有很多开源库, 比如YYModel, MJExtension等等, 都可用于json解析, 但是我做iOS开发两年的时间里用的都是runtime封装的方法, 觉得很好用, 也没有出现问题.

@interface QSMObject : NSObject
//**
  *  传入一个字典, 返回值的当前传入的字典对应的model值
  */
- (id)initWithDic:(NSDictionary *)dic;
//**
  *  传入一个数组, 数组对应的是很多歌字典, 返回值的数组对应的每个字典所对应的model数组
  */
+ (NSMutableArray *) getListArray:(NSArray *) aArray;
@end

#import <objc/runtime.h> //引入runtime
@implementation QSMObject

- (id)initWithDic:(NSDictionary *)dic {
    if (self = [super init]) {
        unsigned int outCount = 0;
        Class currentClass = [self class];
        while (currentClass) {
            //获取当前类所有的属性
            objc_property_t *properties = class_copyPropertyList(currentClass, &outCount);
            for (int i = 0; i < outCount; i++) {
                //获取该类的一个属性指针
                objc_property_t property = properties[i];;
                //property_getName(property) 获取属性的名称
                //initWithCString, c的字符串转OC的字符串
                NSString *propertyNameString =[[NSString alloc] initWithCString:property_getName(property) encoding:NSUTF8StringEncoding];
                //因为id是一个OC的关键字, 你不能声明一个属性名称为id, 所以遇到属性名称是id就携程id_i
                //如果属性名称是id_i, 则把id赋值给当前属性
                if ([propertyNameString isEqualToString:@"id_i"]) {
                    propertyNameString = @"id";
                }
                id value;
                //判断传过来的参数是不是字典类型
                if ([dic isKindOfClass:[NSDictionary class]]) {
                    //根据key获取json数据对应的value
                    //如果对应的可以不存在, 使用字典去获取一个value值, 则返回值为nil
                    value = [dic objectForKey:propertyNameString];
                }
                //如果该值不存在
                if (value == [NSNull null]|| value == nil) {
                    //则返回继续寻找
                    continue;
                }
                //如果值存在
                if (value) {
                    //但度处理名称为id的
                    if ([propertyNameString isEqualToString:@"id"]) {
                        [self setValue:[dic objectForKey:@"id"] forKey:@"id_i"];
                    }else{
                        //根据属性, 使用kvc赋值
                        [self setValue:value forKey:propertyNameString];
                    }
                }
            }
            //最后别忘记释放
            free(properties);
            Class superclass = [currentClass superclass];
            currentClass = superclass;
        }
    }
    return self;
}
+ (NSMutableArray *) getListArray:(NSArray *) aArray
{
    if (aArray == nil) {
        return [NSMutableArray array];
    }
    NSMutableArray *dataArray = [[NSMutableArray alloc] init];
    for(NSDictionary *dic in aArray)
    {
        [dataArray addObject:[[self alloc]initWithDic:dic]];
    }
    return dataArray;
}
+ (NSMutableArray *) getListArray:(NSArray *) aArray
{
    if (aArray == nil) {
        return [NSMutableArray array];
    }
    NSMutableArray *dataArray = [[NSMutableArray alloc] init];
    for(NSDictionary *dic in aArray)
    {
        [dataArray addObject:[[self alloc]initWithDic:dic]];
    }
    return dataArray;
}
@end

如何使用
假如从服务器上获取的数据是这样的

/**
 school = "xx大学";
 group =     {
    teacher = "王老师";
    classNo = 17;
 };
 personlist= [
    {
        name = "小名";
        sex  = "男";
    };
    {
        name = "小丽";
        sex  = "女";
    };
 ];
 */

首先创建对应的mode类

@class GroupModel, PersonModel;
@interface TheClass : JSObject
@property (nonatomic, strong)NSString *school;
@property (nonatomic, strong)GroupModel *group; //注意此处的类型
@property (nonatomic, strong)NSArray <PersonModel *>*personlist; 
@end

@interface GroupModel : JSObject
@property (nonatomic, strong)NSString *teacher;
@property (nonatomic, assign)NSInteger classNo;
@end

@interface PersonModel : JSObject
@property (nonatomic, strong)NSString *name;
@property (nonatomic, strong)NSString *sex;
@end

@implementation TheClass
- (id)initWithDic:(NSDictionary *)dic {
    self = [super initWithDic:dic];
    if (self) {
        if ([dic.allKeys containsObject:@"group"]) {
            GroupModel *model = [[GroupModel alloc] initWithDic:dic[@"group"]];
            _group = model;
        }else {
            _group = nil;
        }
        if ([dic.allKeys containsObject:@"personlist"]) {
            NSArray *personlist = [PersonModel getListArray:dic[@"personlist"]];
            _personlist = personlist;
        }else {
            _personlist = nil;
        }
    }
    return self;
}
@end

@implementation GroupModel

@end

@implementation PersonModel

@end

如果你属性写错, 或者少些, 或者多写, 进行json解析的时候都不会引起crash