JSP学习笔记05-response

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原文链接：http://www.cnblogs.com/wengzhongqin/archive/2012/03/04/2379777.html

本文介绍HttpServletResponse实例response的应用场景，包括生成非字符响应（如验证码图片）、使用sendRedirect进行页面重定向及向客户端添加Cookie。

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response是HttpServletResponse的实例，代表服务器对客户端的响应。

response常用的应用：

1.生成非字符响应（图片，文档。out是jspWriter的实例是字符流）

response.getOutputStream()

实例：验证码

public class CheckCode extends HttpServlet {

    /**
     *
     */
    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        this.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {

        ServletContext sc = this.getServletContext();
        HttpSession session = req.getSession();
        resp.setContentType("image/jpeg");
        Random r = new Random();
        String i = String.valueOf(r.nextInt(10000));
        BufferedImage image = new BufferedImage(50, 20, BufferedImage.TYPE_INT_RGB);
        Graphics g = image.getGraphics();
        g.fillRect(0, 0, 50, 20);
        g.setColor(new Color(0,0,0));
        //g.setColor(new Color(255,0,0));
        g.setFont(new Font("Arial Black", Font.PLAIN, 15));
        g.drawString(i, 10, 13);
        g.dispose();
        ImageIO.write(image, "jpg", resp.getOutputStream());
        session.setAttribute("checkCode", i);
    }


}

2.sendRedirect重定向

response.sendRedirct();

3.向客户端增加cookie

response.addCookie()

request.getCookies()

转载于:https://www.cnblogs.com/wengzhongqin/archive/2012/03/04/2379777.html