字典的升序排列以及字符串的拼接

/**
字典的升序排列以及字符串的拼接

@param params 待排序的字典
@return 拼接好的字符串
*/

+ (NSString *)getStringWithDic:(NSMutableDictionary*)params{
    //排序key
    NSArray *keyArray = [params allKeys];//获取待排序的key
    NSArray *sortArray = [keyArray sortedArrayUsingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
        return [obj1 compare:obj2 ];
    }];//获取排序后的key
    //排序后的以key=value拼接的数组
    NSMutableArray *valueArray = [NSMutableArray array];
    for(NSString *sortSring in sortArray){
        NSString *signSring = [NSString stringWithFormat:@"%@=%@",sortSring,[params objectForKey:sortSring]];
        [valueArray addObject:signSring];
    }
    
    // 就是用“,”把每个排序后拼接的数组，用字符串拼接起来
    NSString *string = [valueArray componentsJoinedByString:@"&"];
    return string;
}