try catch 会降低效率吗? [英] Does try catch decrease efficiency?

问题描述

之间是否存在效率差异:-

Is there an efficiency difference between:-

public boolean canDivisionBeDone(int iA, int iB){

  try{
      float a = iA/iB;
    }catch(Exception e){
    return false;
 }

return true;
}

和

public boolean canDivisionBeDone(int iA, int iB){

 if(iB == 0){
     return false;
 }else{
         float a = iA/iB;
 }

return true;
}

如果是，为什么?

推荐答案

从编码的角度来看，我肯定更喜欢条件式 (a == 0 ? 0 : (a/b))，不是异常处理.这实际上不是异常情况，因此这里不应将异常用于控制流.

From the coding point of view I would definitely prefer a conditional (a == 0 ? 0 : (a/b)), not exception handling. This is actually not an exceptional situation so exception should not be used for control flow here.

关于效率，我写了一个微基准来测试:

Concerning the efficiency, I wrote a micro-benchmark to test this:

@State(Scope.Thread)
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public class MyBenchmark {

    private int a = 10;
    private int b = (int) Math.floor(Math.random());

    @Benchmark
    public float conditional() {
        if (b == 0) {
            return 0;
        } else {
            return a / b;
        }
    }

    @Benchmark
    public float exceptional() {
        try {
            return a / b;
        } catch (ArithmeticException aex) {
            return 0;
        }
    }
}

结果:

Benchmark                Mode  Cnt  Score   Error  Units
MyBenchmark.conditional  avgt  200  7.346 ± 0.326  ns/op
MyBenchmark.exceptional  avgt  200  8.166 ± 0.448  ns/op

由于我对 JMH 很陌生，我不确定我的基准测试是否正确.但是从表面上看结果，特殊"方法有点慢(~10%).老实说，我预计会有更大的差异.

As I am quite new to JMH, I am not sure my benchmark is correct. But taking results at the face value, the "exceptional" approach is somewhat (~10%) slower. To be honest, I've expected much greater difference.

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