import java.io.File;
import java.io.FilenameFilter;

public class Filter implements FilenameFilter {

    @Override
    public boolean accept(File dir, String filename) {
        // TODO Auto-generated method stub
        return filename.endsWith(".java");
    }

}

然后
File filelist = new  File("d:\work");
String[] dirs = filelist.list(new Filter())；

取到后随便你放到什么地方