服务端通过 forward 返回,浏览器 url 地址不会发生变化;服务器通过 redirect 返回,浏览器会重新请求, url 地址会发生变化
forward 跳转页面,是服务端进行页面跳转加载(include)新页面,直接返回到浏览器;redirect 跳转页面,是服务端返回新的 url 地址,浏览器二次发出 url 请求
forward 跳转页面,会携带请求的参数到新的页面;redirect 跳转页面,属于一次全新的 http 请求,无法携带上一次请求的参数
forward 1次;redirect 2次
test servlet
package constxiong;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* test servlet
* @author ConstXiong
* @date 2019-06-26 10:00:34
*/
@WebServlet("/test")
public class TestServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public TestServlet() {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.getWriter().write("This is test.");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
}
请求返回
redirect servlet
package constxiong;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* redirect servlet
* @author ConstXiong
* @date 2019-06-26 10:00:34
*/
@WebServlet("/redirect")
public class RedirectServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public RedirectServlet() {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.sendRedirect("http://www.baidu.com");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
}
请求返回
forward servlet
package constxiong;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* forward servlet
* @author ConstXiong
* @date 2019-06-26 10:00:34
*/
@WebServlet("/forward")
public class ForwardServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public ForwardServlet() {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.getRequestDispatcher("/test").forward(request, response);//forward 跳转到 test 请求
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
}
请求返回
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