哪里有错误
来源：3-3 用户会话Session对象
cj啦啦啦啦
2019-12-13 11:11:40
package com.imooc.session;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* Servlet implementation class SessionIndexServlet
*/
@WebServlet("/session/index")
public class SessionIndexServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public SessionIndexServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session=request.getSession();
String name=(String)session.getAttribute("name");
response.setContentType("text/html;charset=utf-8");
response.getWriter().println("这是首页，当前用户名为:"+name);
}
}
package com.imooc.session;
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;
import javax.servlet.http.HttpSession;
/**
* Servlet implementation class SessionLoginServlet
*/
@WebServlet("/session/login")
public class SessionLoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public SessionLoginServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("用户登录成功");
HttpSession session=request.getSession();
session.setAttribute("name", "张三");
//request.getRequestDispatcher("/session/index").forward(request,response);
response.getWriter().println("这是首页，当前用户名为:");
}
}
1回答
-
好帮手慕酷酷
2019-12-13
同学你好，这里是直接通过URL方式发送请求，所以要将设置session获取session的代码编写在doGet()方法中。而同学写在了doPost方法中，所以不正确。
具体如下：
修改后的代码如下：
package com.imooc.session; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.ServletResponse; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; /** * Servlet implementation class SessionIndexServlet */ @WebServlet("/session/index") public class SessionIndexServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public SessionIndexServlet() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub HttpSession session=request.getSession(); String name=(String)session.getAttribute("name"); response.setContentType("text/html;charset=utf-8"); response.getWriter().println("当前用户名为:"+name); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } }package com.imooc.session; 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; import javax.servlet.http.HttpSession; /** * Servlet implementation class SessionLoginServlet */ @WebServlet("/session/login") public class SessionLoginServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public SessionLoginServlet() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub System.out.println("用户登录成功"); HttpSession session=request.getSession(); session.setAttribute("name", "张三"); //request.getRequestDispatcher("/session/index").forward(request,response); response.getWriter().println("这是首页，当前用户名为:"); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } }结果如图：
如果我的回答解决了你的疑惑，请采纳！祝：学习愉快！
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