MD5签名：按网络请求参数首字母升序排列（获取到的字符串MD5处理）
- (NSString*)stringWithDict:(NSDictionary *) dict{
NSArray * keys = [dict allKeys];
NSArray * sortedArray = [keys sortedArrayUsingComparator:^NSComparisonResult(id obj1,id obj2) {
return[obj1 compare:obj2 options:NSNumericSearch];
}];
NSString * str =@"";
for(NSString * categoryId in sortedArray) {
id value = [dict objectForKey:categoryId];
if([value isKindOfClass:[NSDictionary class]]) {
value = [self stringWithDict:value];
}
if([str length] != 0) {
str = [str stringByAppendingString:@""];
}
str = [str stringByAppendingFormat:@"%@",value];
}
return str;
}
