数据解析及model的封装

我们常常需要对数据进行解析，并且建立model存放数据，今天总结一下具体操作以及它们的封装。

1.数据解析并封装

建立一个文件用来进行数据解析。

.h文件

#import <Foundation/Foundation.h>

@interface DataService : NSObject

//加载

+(id) loadDataWithListName:(NSString *)listName;

@end

.m文件

#import "DataService.h"

@implementation DataService

+(id)loadDataWithListName:(NSString *)listName {

//获取文件
NSString *path = [[NSBundle mainBundle] pathForResource:listName ofType:@"json"];

//读取
NSData *jsonData = [NSData dataWithContentsOfFile:path];

//json--->data
id data = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:nil];

return data;
}

@end

2.model的封装

相比于数据解析的封装，model的封装要相对复杂一点，它的思路是首先要找到映射的字典（要找到key属性的对应关系，json中的key和model类的属性名会形成一个映射关系），然后获取到子类的属性名字，找到set方法，最后进行赋值。

具体实现代码如下：

.h文件

#import <Foundation/Foundation.h>

@interface BaseModel : NSObject

- (void) setvalueForAttributesWithDictionary:(NSDictionary *)keyedValues;

@end

.m文件

#import "BaseModel.h"

@implementation BaseModel

/**
转换方法：
allKeys--->title---->setTitle(字符串)--->setTitle(方法)

*/

- (NSMutableDictionary *)_bulidRalationShip:(NSDictionary *)dic {

NSArray *allkeys = [dic allKeys];

NSMutableDictionary *mutableDic = [NSMutableDictionary dictionary];

for (NSString *key in allkeys) {

if ([key isEqualToString:@"id"]) {

//获取该类的字符串
NSString *className = NSStringFromClass([self class]);
//创建一个string名字
NSString *newString = [NSString stringWithFormat:@"%@id", className];
//将新的string用来做model中的属性名，这里id要注意，不能直接用来做属性名，因为他是关键字
[mutableDic setObject:newString forKey:@"id"];

} else {

//直接将key名字作为model的属性名
[mutableDic setObject:key forKey:key];
}
}

return mutableDic;
}

//创建一个字符串拼接方法
- (SEL)_findSetterMethod:(NSString *)name {

//1.取首字母
NSString *firstLetter = [[name substringFromIndex:1] uppercaseString];

//2.截取剩下的字母
NSString *lastLetter = [name substringFromIndex:1];

//3.拼接
NSString *setterName = [NSString stringWithFormat:@"set%@%@:", firstLetter, lastLetter];

//4.SEL
//从一个方法产生字符串
SEL setter = NSSelectorFromString(setterName);

return setter;
}

//创建一个带字典的属性方法
- (void) setvalueForAttributesWithDictionary:(NSDictionary *)keyedValues {

//1.获取到映射字典
NSMutableDictionary *relationShipDic = [self _bulidRalationShip:keyedValues];

//2.找到set方法
NSArray *allkeys = [relationShipDic allKeys];

for (NSString *key in allkeys) {

NSString *propertName = [relationShipDic objectForKey:key];
SEL method = [self _findSetterMethod:propertName];

//3.赋值
id value = [keyedValues objectForKey:key];

//判断该方法是否能够是吸纳
if ([self respondsToSelector:method]) {

[self performSelector:method withObject:value];
}

}
}