Servlet 中读取文件方法。

public class ReadfileServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// 1.txt没有发布，所以不能访问
		 String filename3 = "/3.txt";
		 filename3 = this.getServletContext().getRealPath(filename3);
		 String filename2 = "/WEB-INF/classes/2.txt";
		 filename2 = this.getServletContext().getRealPath(filename2);
		String filename1 = "/WEB-INF/4.txt";
		filename1 = this.getServletContext().getRealPath(filename1);
		try {
			readfile(filename1);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static void readfile(String filename) throws Exception {
		FileInputStream fs = new FileInputStream(filename);
		byte[] b = new byte[1024];
		int a;
		while ((a = fs.read(b)) != -1) {
			String str = new String(b, 0, a);
			System.out.println(str);
		}
		fs.close();
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request, response);
	}

}