在用户名或者密码框中输入“11‘ or ’1‘ = '1”时,生成的sql语句将为“selec * from userInfo where name = '11' or '1' = '1' and pwd = '11' or '1' = '1'”;该语句永远为真。为了防止sql语句的注入,提高程序的安全性。需要替换危险字符。 Java代码段: public class Checkstr { public String dostring(String str){ str=str.replaceAll(";",""); str=str.replaceAll("&","&"); str=str.replaceAll("<","<"); str=str.replaceAll(">",">"); str=str.replaceAll("'",""); str=str.replaceAll("--",""); str=str.replaceAll("/",""); str=str.replaceAll("%",""); return str; } } 来源: https://www.cnblogs.com/tbyang/p/3362889.html