Servlet 重定向

重定向和请求转发的区别

• 相同点：实现页面跳转
• 不同点：请求转发url不变，重定向url改变。

代码

向浏览器输出图片

public class Servlet_1 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("image/jpeg");
        String path = "/WEB-INF/classes/img.png";
        OutputStream out = resp.getOutputStream();
        InputStream in = this.getServletContext().getResourceAsStream(path);
        int len;
        byte[] buffer = new byte[1024];
        while ((len = in.read(buffer))>0){
            out.write(buffer,0,len);
        }
    }

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

public class Redirect extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.sendRedirect("s1");
 //对该servlet的请求都会定向到s1，s1是<url-pattern>/s1</url-pattern>，在web.xml里，也就是另外一个servlet
    }

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