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1. 字符串与NSData

• 将string字符串转换为NSData

//NSString -> NSData  
NSData *data = [@"520it.com" dataUsingEncoding:NSUTF8StringEncoding];  

• 将NSData转换为NSDatastring字符串

//NSData -> NSString  
NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];  

2. 字符串与数组

• 将string字符串转换为array数组

 NSArray  *array = [str componentsSeparatedByString:@"-"];//其中"-"号为分隔符

• 将array数组转换为string字符串

 NSString *str = [array componentsJoinedByString:@"-"];//其中"-"号为分隔符

3. 字符串与字典

• 字符串转字典

+ (NSDictionary *)dictionaryWithJsonString:(NSString *)jsonString {
    if (jsonString == nil) {
        
        return nil;
        
    }
    
    NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
    
    NSError *err;
    
    NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:jsonData
                         
                                                        options:NSJSONReadingMutableContainers
                         
                                                          error:&err];
    
    if(err) {
        
        NSLog(@"json解析失败：%@",err);
        
        return nil;
        
    }
    
    return dic;
    
}

• 字典转字符串

+ (NSString*)dictionaryToJson:(NSDictionary *)dic

{

NSError *parseError = nil;

NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dic options:NSJSONWritingPrettyPrinted error:&parseError];

return [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];

}