Servlet--转发和重定向

标签：servlet   转发和重定向   

• Servlet的跳转有2种，一种是转发，一种是重定向。

<strong><span style="font-size:14px;"></span></strong><pre name="code" class="java"><strong style="font-family: Arial, Helvetica, sans-serif; font-size: 12px; background-color: rgb(255, 255, 255);"><span style="font-size:14px;"></span></strong><pre name="code" class="java" style="display: inline !important;">httpServletResponse.sendRedirect("/linkin/Linkin.jsp");

httpServletRequest.getRequestDispatcher("/Linkin.jsp").forward(httpServletRequest, httpServletResponse);

<jsp:forward page="Linkin.jsp" />

• 在对比整理这2种Servlet之前，我们先来看下RequestDispatcher这个接口。

forward和include方法接收的两个参数必须是传递给当前Servlet的service方法的那两个ServletRequest和ServletResponse对象，或者是对它们进行了包装的ServletRequestWrapper 或ServletResponseWrapper对象。 

• OK，现在来对比整理转发和重定向。

重定向过程：客户浏览器发送http请求----》web服务器接受后发送302状态码响应及对应新的location给客户浏览器--》客户浏览器发现是302响应，则自动再发送一个新的http请求，请求url是新的location地址----》服务器根据此请求寻找资源并发送给客户。在这里location可以重定向到任意URL，既然是浏览器重新发出了请求，则就没有什么request传递的概念了。在客户浏览器路径栏显示的是其重定向的路径，客户可以观察到地址的变化的。

• 怎么选择是重定向还是转发呢？

package linkin;

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

/**
 * @author LinkinPark
 * @author 2015-7-8
 * @Descri 转发
 */
public class LinkinServlet extends HttpServlet
{
	private static final long serialVersionUID = 1L;

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
	{
		req.setCharacterEncoding("UTF-8");
		String userName = req.getParameter("userName");
		String passWord = req.getParameter("passWord");
		req.setAttribute("userName", userName);
		req.getSession().setAttribute("passWord", passWord);
		req.getRequestDispatcher("/Linkin.jsp").forward(req, resp);
	}

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

}

package linkin;

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

/**
 * @author LinkinPark
 * @author 2015-7-8
 * @Descri 重定向
 */
public class LinkinServlet extends HttpServlet
{
	private static final long serialVersionUID = 1L;

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
	{
		req.setCharacterEncoding("UTF-8");
		String userName = req.getParameter("userName");
		String passWord = req.getParameter("passWord");
		req.setAttribute("userName", userName);
		req.getSession().setAttribute("passWord", passWord);
		resp.sendRedirect("/linkin/Linkin1.jsp");
	}

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

}

Servlet--转发和重定向

标签：servlet   转发和重定向   

原文地址：http://blog.csdn.net/u011794238/article/details/46801761