ttt

//改目录下文件名的扩展名
import java.io.File;
public class re {
	public static void main(String[] args){
		File file = new File("D:\\tmep");
		String pre = new String("sql");
		String aft = new String("txt");
		run(file,pre,aft);
	}
	public static void run(File f,String from,String to) {
		
		if (f.isFile())	renname(f,from,to);
		else for (File a:f.listFiles())	run(a,from,to);
		
	}
	public static String getSubname(File f) {
		String[] names = f.getName().split("\\.");
		if (names.length>1)		return names[names.length-1];
		else return "";
	}
	public static String getname(File f ) {
		String[] names = f.getName().split("\\.");
		String filename = names[0];
		for(int i=1;i<names.length-1;i++) {
			filename = filename+"."+names[i];
		}
		return filename;
	}
	public static void renname(File renf,String from,String to) {
			if (renf.isFile()&&(getSubname(renf).equalsIgnoreCase(from))) {
			renf.renameTo(new File(getname(renf)+"."+to));
			System.out.println(renf.getPath()+"->"+getname(renf)+"."+to);
		}
	}

}