问题描述:
public static string replace(string test,string rep,string with);
//将test中的rep替换为with(不要使用jdk自带的replace)。 怎么实现呀
问题解答:
public static String rep(String source, String rep, String w) throws Exception {
//get the index of the word you are going to replace
int index = source.indexOf(rep);
if(source.indexOf(rep) == -1)
throw new Exception("Invalid input.");
//separate the source word into 2 parts:
//front part: before the word you want to replace
//back part: after the word you want to replace
String frontPart = source.substring(0,index);
String backPart = source.substring(index+rep.length(),
source.length());
return frontPart+w+backPart;
}
你应该知道你不能改变任何String类的东西,String 类是唯一个不能改变的类!!!!你如果需要加功能,你可以做个别的类extends String这个类,然后再overwrite它的replace方法。这个方法用.subString().equals("")也可以