Switch 可能转化成多种不同算法的代码。其中最常见的是跳转表和比较链/树。当switch用比较链的方式转化时，编译器会产生if-else-if的嵌套代码，并按照顺序进行比较，匹配时就跳转到满足条件的语句执行。所以可以对case的值依照发生的可能性进行排序，把最有可能的放在第一位，这样可以提高性能。-Switch could be transformed into a variety of different algorithm code. One of the most common is to jump the table and compare chain/tree. When the switch comparison chain transformation, the compiler will generate a nested if-else-if code, in order to compare and match Jump to meet the conditions of the statement is executed. So can the value of the case in accordance with the likelihood of sorting, most likely the first place, so you can improve performance.