老师，本来是好的，再次运行就出错了，不知道什么原因
可以下载信息,但是文件名不对,后缀不对,是图片可以用画图工具打开, 说明传输没有问题
下载就是这样的文件, 文件名是访问的URI名
我的浏览器总是乱码，每次打开的时候正常，一秒后自己就乱码了
servletdemo.rar
老师，包给你了，帮我看一下
问题1：为什么用servletContext.getAttribute对应获取value，再转成HttpSession。因为前者是可以从全局中获取吗。HttpSession中客户端浏览器换了，就没有对应的SessionID，就不行了吗？因此，我要判断重复登录，肯定要用不同的浏览器进行重复登录，所以我要从全局中获取value，然后再转成httpSession给到我当前对应的客户端浏览器?
问题2：。为什么要从全局中删除value，再销毁httpSession？我并不理解两者对应去除的分别是什么？
我想问下 ，这个方法的作用是什么？为什么可以调用这个方法。
浏览器里面访问本机Tomcat为什么会出现这种情况呢？怎么解决？
老师，自从那个@WebServlet注解使用后，tomcat一运行下面就全部都红了，看别人的问题后，别人导入的是别的包，我导入的包也都是正常的，都是Javax的，怎么解决
老师，在ajax这一章中的实例要是真的部署在服务器上，不同用户访问时进行的数据操作（增，删，改）是针对同一个列表吗，如果要想为每个用户设置一个表可以怎么实现呢
为什么这个标红的，也是从DemoServlet那边复制过来的路径
老师我启动tomcat时候httpsession为什么会创建2次啊
一：遇到的问题：
老师，这里的td标签里面id属性的值为什么既加单引号又加双引号
二：代码区：
str+= "<tr align='center'><td id='"+this.userid+"'>"+this.userid +"</td></tr>"
遇到的问题：
老师我这里将用户数据回填到上方的表格时为什么在input框里后面会多出空白部分，导致我更新用户时出现
代码如下：
function preUpdateUser(userid){ var arr = new Array(); //$("#"+userid):通过preUpdateUser函数传递的参数获取当前行内id为uerid的那个td标签 找离该td最近的tr，找到该td所在的这行数据 //.children获取每个td子元素，遍历所有td元素只取前4个 index迭代因子,ele迭代的每个元素 $("#"+userid).closest("tr").children().each(function(index,ele){ if(index <=3){ arr[index]= ele.innerText;//存储到数组 } }); //将获取到的当前行的前四组数据回填到上方用户信息的表单中 $("#userid").val(arr[0]); $("#username").val(arr[1]); $("#usersex").val(arr[2]); $("#userbirth").val(arr[3]); $("#userid").attr("readonly",true); //设置id不允许修改 }
老师帮忙看看这个报错
服务器报错信息
24-Feb-2021 19:34:06.220 严重 [http-nio-8080-exec-5] org.apache.catalina.core.StandardWrapperValve.invoke 在路径为/webdemo_war的上下文中，Servlet[com.example.webdemo.web.servlet.UserLoginServlet]的Servlet.service（）引发了具有根本原因的异常Servlet执行抛出一个异常 java.util.MissingResourceException: Can't find bundle for base name db, locale zh_CN at java.base/java.util.ResourceBundle.throwMissingResourceException(ResourceBundle.java:2055) at java.base/java.util.ResourceBundle.getBundleImpl(ResourceBundle.java:1689) at java.base/java.util.ResourceBundle.getBundleImpl(ResourceBundle.java:1593) at java.base/java.util.ResourceBundle.getBundleImpl(ResourceBundle.java:1556) at java.base/java.util.ResourceBundle.getBundle(ResourceBundle.java:857) at com.example.webdemo.commons.JdbcUtils.<clinit>(JdbcUtils.java:14) at com.example.webdemo.dao.impl.UserLoginDaoImpl.selectUsersByUserNameAndUserPwd(UserLoginDaoImpl.java:17) at com.example.webdemo.service.impl.UserLoginServiceImpl.userLogin(UserLoginServiceImpl.java:14) at com.example.webdemo.web.servlet.UserLoginServlet.doPost(UserLoginServlet.java:30) at javax.servlet.http.HttpServlet.service(HttpServlet.java:652) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:887) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1684) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.base/java.lang.Thread.run(Thread.java:832) 24-Feb-2021 19:34:10.829 严重 [http-nio-8080-exec-6] org.apache.catalina.core.StandardWrapperValve.invoke 在路径为/webdemo_war的上下文中，Servlet[com.example.webdemo.web.servlet.UserLoginServlet]的Servlet.service（）引发了具有根本原因的异常Servlet执行抛出一个异常 java.lang.NoClassDefFoundError: Could not initialize class com.example.webdemo.commons.JdbcUtils at com.example.webdemo.dao.impl.UserLoginDaoImpl.selectUsersByUserNameAndUserPwd(UserLoginDaoImpl.java:17) at com.example.webdemo.service.impl.UserLoginServiceImpl.userLogin(UserLoginServiceImpl.java:14) at com.example.webdemo.web.servlet.UserLoginServlet.doPost(UserLoginServlet.java:30) at javax.servlet.http.HttpServlet.service(HttpServlet.java:652) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:887) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1684) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.base/java.lang.Thread.run(Thread.java:832) 24-Feb-2021 19:35:33.939 严重 [http-nio-8080-exec-8] org.apache.catalina.core.StandardWrapperValve.invoke 在路径为/webdemo_war的上下文中，Servlet[com.example.webdemo.web.servlet.UserLoginServlet]的Servlet.service（）引发了具有根本原因的异常Servlet执行抛出一个异常 java.lang.NoClassDefFoundError: Could not initialize class com.example.webdemo.commons.JdbcUtils at com.example.webdemo.dao.impl.UserLoginDaoImpl.selectUsersByUserNameAndUserPwd(UserLoginDaoImpl.java:17) at com.example.webdemo.service.impl.UserLoginServiceImpl.userLogin(UserLoginServiceImpl.java:14) at com.example.webdemo.web.servlet.UserLoginServlet.doPost(UserLoginServlet.java:30) at javax.servlet.http.HttpServlet.service(HttpServlet.java:652) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:887) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1684) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.base/java.lang.Thread.run(Thread.java:832) 24-Feb-2021 19:35:40.832 严重 [http-nio-8080-exec-9] org.apache.catalina.core.StandardWrapperValve.invoke 在路径为/webdemo_war的上下文中，Servlet[com.example.webdemo.web.servlet.UserLoginServlet]的Servlet.service（）引发了具有根本原因的异常Servlet执行抛出一个异常 java.lang.NoClassDefFoundError: Could not initialize class com.example.webdemo.commons.JdbcUtils at com.example.webdemo.dao.impl.UserLoginDaoImpl.selectUsersByUserNameAndUserPwd(UserLoginDaoImpl.java:17) at com.example.webdemo.service.impl.UserLoginServiceImpl.userLogin(UserLoginServiceImpl.java:14) at com.example.webdemo.web.servlet.UserLoginServlet.doPost(UserLoginServlet.java:30) at javax.servlet.http.HttpServlet.service(HttpServlet.java:652) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:887) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1684) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.base/java.lang.Thread.run(Thread.java:832) 24-Feb-2021 19:35:49.856 严重 [http-nio-8080-exec-10] org.apache.catalina.core.StandardWrapperValve.invoke 在路径为/webdemo_war的上下文中，Servlet[com.example.webdemo.web.servlet.UserLoginServlet]的Servlet.service（）引发了具有根本原因的异常Servlet执行抛出一个异常 java.lang.NoClassDefFoundError: Could not initialize class com.example.webdemo.commons.JdbcUtils at com.example.webdemo.dao.impl.UserLoginDaoImpl.selectUsersByUserNameAndUserPwd(UserLoginDaoImpl.java:17) at com.example.webdemo.service.impl.UserLoginServiceImpl.userLogin(UserLoginServiceImpl.java:14) at com.example.webdemo.web.servlet.UserLoginServlet.doPost(UserLoginServlet.java:30) at javax.servlet.http.HttpServlet.service(HttpServlet.java:652) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:887) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1684) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.base/java.lang.Thread.run(Thread.java:832)
webdemo.rar
老师上面../userManager.do这个有没有一个页面所有请求路径基于项目路径的写法？
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。为什么要从全局中删除value，再销毁httpSession？我并不理解两者对应去除的分别是什么？
京公网安备 11011402011233号