indexOf(String s),substring(int startpoint),trim()的用法实例

package com.chap5.part1;

public class Example5_4 {
    public static void main(String[] args) {
        String path = "C:\\myfile\\2000\\result.txt";
        //st.indexOf（String st1）,返回st1字符串在st中的开始位置。
        int index = path.lastIndexOf("\\");
        //st.substring(int number),返回st中number位置后面的字符串。
        String fileName = path.substring(index+1);
        String newName = fileName.replaceAll(".txt", ".java");
        System.out.println(index);
        System.out.println(fileName);
        System.out.println(newName);

        String st = "   we are student";
        System.out.println(st);
        //st.trim();去掉st前面的空格
        st = st.trim();
        System.out.println(st);
    }
}