字节码中Switch语句的表示形式和效率? [英] Representation and efficiency of Switch statements in bytecode?

问题描述

尽管switch语句可以表示为一系列if语句，但是当将Java switch语句编译为字节码时，似乎使用了另一种方法.

Though a switch statement can be represented as a series of if statements, it appears that when a Java switch statement is compiled into bytecode, a different approach is used.

• 字节码使用什么表示?
• 我认为这种替代表示是出于效率原因，那么效率与仅if语句表示的效率相比如何?
• 还有其他因素导致使用此表示形式吗?

推荐答案

阅读

Read the spec . In Java, if you code a switch statement, then depending on various things the switch is converted into a tableswitch instruction in bytecode. Essentially a jump table. What the bytecode looks like may be irrelavent though, if the JIT can optimize it into something more efficient. This is of course, platform dependent.

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