经常有人问题，在servlet里面forward到一个页面之后，浏览器总是汉字的乱码。经调试发现，在servlet里面不能调用 response.getWriter()方法。

servlet 如下

package test;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class TestServlet extends HttpServlet ...{
  @Override
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException ...{
//    PrintWriter out = response.getWriter();
    RequestDispatcher requestDispatcher = request.getRequestDispatcher("/test/test2.jsp");
    requestDispatcher.forward(request, response);
  }
}

去掉后，就可以正常显示汉字了，如果加上了，无论后面做了什么，forward的页面都显示乱码了！