JAVA-EE解析重定向和转发的区别------计算机网络经典

小鱼儿 2024-02-23 08:08 16阅读 0赞

>     package com.bjpowernode.javaweb.servlet;
>     
>     import com.bjpowernode.javaweb.Bean.User;
>     import jakarta.servlet.ServletException;
>     import jakarta.servlet.http.HttpServlet;
>     import jakarta.servlet.http.HttpServletRequest;
>     import jakarta.servlet.http.HttpServletResponse;
>     
>     import java.io.IOException;
>     
>     public class AServlet extends HttpServlet
>     {
>         @Override
>         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
>         {
>             User user = new User();
>             user.setId("1111");
>             user.setUsername("杰克");
>             request.setAttribute("user",user);
>     //        转发是服务器的内部跳转,并没有涉及到浏览器的请求,所以不管转发多少次,都是同一个浏览器发过来的请求
>     //        request.getRequestDispatcher("/A").forward(request,response);
>             //response具有响应能力,它可以把这个路径重新响应给浏览器,浏览器会再次向服务器提交一次全新请求
>             //所以重定向会导致地址栏上的地址发生变化(因为不是同一个请求了)
>             response.sendRedirect(request.getContextPath() + "/B");
>         }
>     }
> 
>     package com.bjpowernode.javaweb.servlet;
>     
>     import com.bjpowernode.javaweb.Bean.User;
>     import jakarta.servlet.ServletException;
>     import jakarta.servlet.http.HttpServlet;
>     import jakarta.servlet.http.HttpServletRequest;
>     import jakarta.servlet.http.HttpServletResponse;
>     
>     import java.io.IOException;
>     
>     public class AServlet extends HttpServlet
>     {
>         @Override
>         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
>         {
>             User user = new User();
>             user.setId("1111");
>             user.setUsername("杰克");
>             request.setAttribute("user",user);
>     //        转发是服务器的内部跳转,并没有涉及到浏览器的请求,所以不管转发多少次,都是同一个浏览器发过来的请求
>     //        request.getRequestDispatcher("/A").forward(request,response);
>             //response具有响应能力,它可以把这个路径重新响应给浏览器,浏览器会再次向服务器提交一次全新请求
>             //所以重定向会导致地址栏上的地址发生变化(因为不是同一个请求了)
>             response.sendRedirect(request.getContextPath() + "/B");
>         }
>     }

>     package com.bjpowernode.javaweb.servlet;
>     
>     import jakarta.servlet.ServletException;
>     import jakarta.servlet.http.HttpServlet;
>     import jakarta.servlet.http.HttpServletRequest;
>     import jakarta.servlet.http.HttpServletResponse;
>     
>     import java.io.IOException;
>     import java.io.PrintWriter;
>     
>     public class BServlet extends HttpServlet
>     {
>         @Override
>         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
>         {
>             response.setContentType("text/html;charset=UTF-8");
>             PrintWriter out = response.getWriter();
>             Object user = request.getAttribute("user");
>             //转发的话,地址栏上还是原地址,因为是之前的请求和响应对象,在同一个请求域下
>             out.println(user);
>         }
>     }
> 
>     package com.bjpowernode.javaweb.servlet;
>     
>     import jakarta.servlet.ServletException;
>     import jakarta.servlet.http.HttpServlet;
>     import jakarta.servlet.http.HttpServletRequest;
>     import jakarta.servlet.http.HttpServletResponse;
>     
>     import java.io.IOException;
>     import java.io.PrintWriter;
>     
>     public class BServlet extends HttpServlet
>     {
>         @Override
>         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
>         {
>             response.setContentType("text/html;charset=UTF-8");
>             PrintWriter out = response.getWriter();
>             Object user = request.getAttribute("user");
>             //转发的话,地址栏上还是原地址,因为是之前的请求和响应对象,在同一个请求域下
>             out.println(user);
>         }
>     }

>     package com.bjpowernode.javaweb.Bean;
>     
>     import java.io.Serializable;
>     import java.util.Objects;
>     
>     public class User implements Serializable
>     {
>         private String id;
>         private String username;
>     
>         @Override
>         public boolean equals(Object o) {
>             if (this == o) return true;
>             if (o == null || getClass() != o.getClass()) return false;
>             User user = (User) o;
>             return Objects.equals(id, user.id) && Objects.equals(username, user.username);
>         }
>     
>         @Override
>         public int hashCode() {
>             return Objects.hash(id, username);
>         }
>     
>         @Override
>         public String toString() {
>             return "User{" +
>                     "id='" + id + '\'' +
>                     ", username='" + username + '\'' +
>                     '}';
>         }
>     
>         public String getId() {
>             return id;
>         }
>     
>         public void setId(String id) {
>             this.id = id;
>         }
>     
>         public String getUsername() {
>             return username;
>         }
>     
>         public void setUsername(String username) {
>             this.username = username;
>         }
>     
>         public User() {
>         }
>     
>         public User(String id, String username) {
>             this.id = id;
>             this.username = username;
>         }
>     }
> 
>     package com.bjpowernode.javaweb.Bean;
>     
>     import java.io.Serializable;
>     import java.util.Objects;
>     
>     public class User implements Serializable
>     {
>         private String id;
>         private String username;
>     
>         @Override
>         public boolean equals(Object o) {
>             if (this == o) return true;
>             if (o == null || getClass() != o.getClass()) return false;
>             User user = (User) o;
>             return Objects.equals(id, user.id) && Objects.equals(username, user.username);
>         }
>     
>         @Override
>         public int hashCode() {
>             return Objects.hash(id, username);
>         }
>     
>         @Override
>         public String toString() {
>             return "User{" +
>                     "id='" + id + '\'' +
>                     ", username='" + username + '\'' +
>                     '}';
>         }
>     
>         public String getId() {
>             return id;
>         }
>     
>         public void setId(String id) {
>             this.id = id;
>         }
>     
>         public String getUsername() {
>             return username;
>         }
>     
>         public void setUsername(String username) {
>             this.username = username;
>         }
>     
>         public User() {
>         }
>     
>         public User(String id, String username) {
>             this.id = id;
>             this.username = username;
>         }
>     }

>     <?xml version="1.0" encoding="UTF-8"?>
>     <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
>              xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>              xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
>              version="4.0">
>         <servlet>
>             <servlet-name>listDept</servlet-name>
>             <servlet-class>com.bjpowernode.oa.web.action.DeptListServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>listDept</servlet-name>
>     
>             <url-pattern>/dept/list</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>detail</servlet-name>
>             <servlet-class>com.bjpowernode.oa.web.action.DetailServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>detail</servlet-name>
>             <url-pattern>/dept/detail</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>delete</servlet-name>
>             <servlet-class>com.bjpowernode.oa.web.action.DeleteServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>delete</servlet-name>
>             <url-pattern>/dept/delete</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>save</servlet-name>
>             <servlet-class>com.bjpowernode.oa.web.action.SaveServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>save</servlet-name>
>             <url-pattern>/dept/save</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>edit</servlet-name>
>             <servlet-class>com.bjpowernode.oa.web.action.EditServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>edit</servlet-name>
>             <url-pattern>/dept/edit</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>modify</servlet-name>
>             <servlet-class>com.bjpowernode.oa.web.action.ModifyServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>modify</servlet-name>
>             <url-pattern>/dept/modify</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>A</servlet-name>
>             <servlet-class>com.bjpowernode.javaweb.servlet.AServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>A</servlet-name>
>             <url-pattern>/A</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>B</servlet-name>
>             <servlet-class>com.bjpowernode.javaweb.servlet.BServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>B</servlet-name>
>             <url-pattern>/B</url-pattern>
>         </servlet-mapping>
>     </web-app>
> 
>     <?xml version="1.0" encoding="UTF-8"?>
>     <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
>              xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>              xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
>              version="4.0">
>         <servlet>
>             <servlet-name>listDept</servlet-name>
>             <servlet-class>com.bjpowernode.oa.web.action.DeptListServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>listDept</servlet-name>
>     
>             <url-pattern>/dept/list</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>detail</servlet-name>
>             <servlet-class>com.bjpowernode.oa.web.action.DetailServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>detail</servlet-name>
>             <url-pattern>/dept/detail</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>delete</servlet-name>
>             <servlet-class>com.bjpowernode.oa.web.action.DeleteServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>delete</servlet-name>
>             <url-pattern>/dept/delete</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>save</servlet-name>
>             <servlet-class>com.bjpowernode.oa.web.action.SaveServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>save</servlet-name>
>             <url-pattern>/dept/save</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>edit</servlet-name>
>             <servlet-class>com.bjpowernode.oa.web.action.EditServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>edit</servlet-name>
>             <url-pattern>/dept/edit</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>modify</servlet-name>
>             <servlet-class>com.bjpowernode.oa.web.action.ModifyServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>modify</servlet-name>
>             <url-pattern>/dept/modify</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>A</servlet-name>
>             <servlet-class>com.bjpowernode.javaweb.servlet.AServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>A</servlet-name>
>             <url-pattern>/A</url-pattern>
>         </servlet-mapping>
>         <servlet>
>             <servlet-name>B</servlet-name>
>             <servlet-class>com.bjpowernode.javaweb.servlet.BServlet</servlet-class>
>         </servlet>
>         <servlet-mapping>
>             <servlet-name>B</servlet-name>
>             <url-pattern>/B</url-pattern>
>         </servlet-mapping>
>     </web-app>