java怎么split路径文件名？

D:\Program Files\apache-tomcat-6.0.37-windows-x86\apache-tomcat-6.0.37\webapps\RecruitmentSolution\upload\recruitmentAgency.txt
我想在recruitmentAgency.txt 前面加个数字或者在recruitmentAgency加个数字？该怎么split呢？？求助啊

最后的效果是
D:\Program Files\apache-tomcat-6.0.37-windows-x86\apache-tomcat-6.0.37\webapps\RecruitmentSolution\upload\1_recruitmentAgency.txt
或者是D:\Program Files\apache-tomcat-6.0.37-windows-x86\apache-tomcat-6.0.37\webapps\RecruitmentSolution\upload\1_recruitmentAgency_1.txt
--------------------编程问答--------------------

    	String str ="D:\\Program Files\\apache-tomcat-6.0.37-windows-x86\\apache-tomcat-6.0.37\\webapps\\RecruitmentSolution\\upload\\recruitmentAgency.txt"; 

    	String[] s = str.split("\\\\");

--------------------编程问答-------------------- 如果你非要用split做的话：





		String fileName = "";

		String str ="D:\\Program Files\\apache-tomcat-6.0.37-windows-x86\\apache-tomcat-6.0.37\\webapps\\RecruitmentSolution\\upload\\recruitmentAgency.txt"; 

        String[] s = str.split("\\\\");

      	s[s.length - 1] = "1_"+s[s.length - 1]; //"1_"+s[s.length - 1] + "_1"

      	for (String string : s) {

      		fileName += (string + "\\");

      	}

      	fileName = fileName.substring(0, fileName.length() - 1);

      	System.out.println(fileName);

--------------------编程问答--------------------



	String str="D:\\Program Files\\apache-tomcat-6.0.37-windows-x86\\apache-tomcat-6.0.37\\webapps\\RecruitmentSolution\\upload\\recruitmentAgency.txt";

//    	str = str.replaceAll("(?=recruitmentAgency.txt)", "1_");//加前面

    	str = str.replaceAll("(?<=recruitmentAgency.txt)", "_1");//加后面

    	System.out.println(str);

补充：Java ,  Java相关