jsp的servlet容器跳转是出现乱码(转载) 挺经典的

今天写程序时，用一个Servlet跳转到JSP页面后该JSP页面出现乱码，但是直接在IE运行该JSP不出现乱码

出问题的代码如下：

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
PrintWriter out = response.getWriter();
response.setContentType("type=text/html; charset=GBK");
String username = request.getParameter("username");
out = response.getWriter();
out.println("<html><head><title>处理</title></head><body>");
Check check = new Check();
check.setName(username);
System.out.println(check.getName());
if(check.checkName()){
request.setAttribute("username", check.getName());
request.getRequestDispatcher("login_success.jsp").forward(request, response);
}else
request.getRequestDispatcher("faile.jsp").forward(request, response);
out.println("</body></html>");
}

问题如下：如果用该servlet运行跳转到JSP页面，就会出现乱码，如果把PrintWriter out去掉，就不会出现乱码。

具体原因：因为在设置编码之前就获得PrintWriter对象，所以必然出现乱码

解决办法：在获得PrintWriter对象之前就设置好编码，这样就不会出现问题

正确代码：

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub 
        
        request.setCharacterEncoding("GBK");
        response.setContentType("GBK");
        PrintWriter out = null;
        response.setContentType("type=text/html; charset=GBK");
        String username = request.getParameter("username");
        username = new String(username.getBytes("iso-8859-1"),"GBK");
        out = response.getWriter();
        out.println("<html><head><title>处理</title></head><body>");
        Check check = new Check();
        check.setName(username);
        System.out.println(check.getName());
        
        if(check.checkName()){
            request.setAttribute("username", check.getName());
            request.getRequestDispatcher("login_success.jsp").forward(request, response);
        }else
            request.getRequestDispatcher("faile.jsp").forward(request, response);
        out.println("</body></html>");
    }           

这样就解决问题了