今天用string.replaceAll(“\\n”,”\n”);本义是想将字符串里的字符串\n转换成字符\n,哪知道却没效果,心想可能是转义字符有问题,于是试着改成replaceAll(“\\“,test”)想看看是啥状况,哪知却出现了Unexpected internal error near index 1的错误.google了一下,居然在sun的Bug Database里面找到了,不过已经被定性为 Closed, not a bug.Evaluation 里写道:This is not a bug. As mentioned in the spec, slashes in source code are interpreted once by javac and then again by the regex engine.

也就是说,对于replaceAll(“\\“,test”),\\先被javac解释成\,然后交给正则引擎,正则引擎看到\后认为这是一个转义字符,于是去找后面的字符,却发现没有了,然后报错.string.replaceAll(“\\n”,”\n”) doesn’t work的原因也很好解释了,\\n到了正则引擎处就成了\n(换行符)了,而不是\n

知道原因就好办了,改成string.replaceAll(“\\\\n”,”\n”); //it works!