Java replaceFirst 报错

            String s = "[~E(a,b)|dE(a,c)|Ins(a,d)]";
            s = s.replaceFirst("[","");

报错 Unclosed character class near index 0

java里的replaceFirst包括replaceAll等，第一个参数都是正则表达式，所以要给[添加转义符：

            String s = "[~E(a,b)|dE(a,c)|Ins(a,d)]";
            s = s.replaceFirst("\\[","");