Redis, please don't exists any more.

Today, I accidentally saw a piece of code that was previously optimized for a similar problem. But this problem again and again again appear, really think yards nong, also not who can be good. Details determine success or failure, the style of doing things, really will hinder the development of a person.

Nonsense not much to say, directly on the code:

Unfriendly use
if (jedis.exists (key)) {
	String value = Jedis.get (key);
	Do ("Target code 1");
	...
} else{do
	("Target code 2");
	...
}

Friendly way to use
String value = Jedis.get (key);
if (value!=null) {do
	("Target code 1");
	...
} else{do
	("Target code 2");
	...
}

Unfriendly way to make two network communications with Redis, but only once in a friendly way. One-fold performance boost.

The same is if else.

But some people are lost in if, others find the exit in the else.