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？
为什么文件重新指定的编码格式改完了还是乱码
使用xml文件配置网页报500错误是咋回事，老师能帮忙看看嘛
<?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" metadata-complete="false"> <context-param> <param-name>key1</param-name> <param-value>BJSXT</param-value> </context-param> <context-param> <param-name>key2</param-name> <param-value>BJSXT</param-value> </context-param> <servlet> <servlet-name>demoServlet</servlet-name> <servlet-class>com.example.demo.DemoServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>demoServlet</servlet-name> <url-pattern>/demo.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>getRequestDataServlet</servlet-name> <servlet-class>com.example.demo.GetRequestDataServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>getRequestDataServlet</servlet-name> <url-pattern>/getinfo.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>getRequestHeaderServlet</servlet-name> <servlet-class>com.example.demo.GetRequestHeaderServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>getRequestHeaderServlet</servlet-name> <url-pattern>/getHeader.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>LanguageServlet</servlet-name> <servlet-class>com.example.demo.LanguageServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>LanguageServlet</servlet-name> <url-pattern>/Languages.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>RespByteServlet</servlet-name> <servlet-class>com.example.demo.RespByteServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>RespByteServlet</servlet-name> <url-pattern>/RespByte.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>RedirectServlet</servlet-name> <servlet-class>com.example.demo.RedirectServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>RedirectServlet</servlet-name> <url-pattern>/Redirect.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>DownFileServlet</servlet-name> <servlet-class>com.example.demo.DownFileServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>DownFileServlet</servlet-name> <url-pattern>/Down.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>GetBaseInfoServlet</servlet-name> <servlet-class>com.example.demo.GetBaseInfoServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>GetBaseInfoServlet</servlet-name> <url-pattern>/getBaseInfo.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>ContextReadInfoServlet</servlet-name> <servlet-class>com.example.demo.ContextReadInfoServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>ContextReadInfoServlet</servlet-name> <url-pattern>/Context.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>GlobalContainerServlet</servlet-name> <servlet-class>com.example.demo.GlobalContainerServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>GlobalContainerServlet</servlet-name> <url-pattern>/Global.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>GetConfigInfoServlet</servlet-name> <servlet-class>com.example.demo.GetConfigInfoServlet</servlet-class> <init-param> <param-name>key1</param-name> <param-value>BJSXT</param-value> </init-param> <init-param> <param-name>key2</param-name> <param-value>ITBZ</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>GetConfigInfoServlet</servlet-name> <url-pattern>/Config.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>CreatCookieSrvlet</servlet-name> <servlet-class>com.example.demo.CreatCookieSrvlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>CreatCookieSrvlet</servlet-name> <url-pattern>/Cookie.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>GetCookieDataServlet</servlet-name> <servlet-class>com.example.demo.GetCookieDataServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>GetCookieDataServlet</servlet-name> <url-pattern>/GetCookie.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>WelcomeServlet</servlet-name> <servlet-class>com.example.demo.WelcomeServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>WelcomeServlet</servlet-name> <url-pattern>/Welcome.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>CreateHttpSessionServlet</servlet-name> <servlet-class>com.example.demo.CreateHttpSessionServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>CreateHttpSessionServlet</servlet-name> <url-pattern>/CreatSession.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>GetHttpSessionDataServlet</servlet-name> <servlet-class>com.example.demo.GetHttpSessionDataServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>GetHttpSessionDataServlet</servlet-name> <url-pattern>/GetSessionData.do</url-pattern> </servlet-mapping> <session-config> <session-timeout>1</session-timeout> </session-config> <servlet> <servlet-name>WelcomeSessionServlet</servlet-name> <servlet-class>com.example.demo.WelcomeSessionServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>WelcomeSessionServlet</servlet-name> <url-pattern>/WelcomeSession.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>AutoStartServlet</servlet-name> <servlet-class>com.example.demo.AutoStartServlet</servlet-class> <init-param> <param-name>path</param-name> <param-value>image</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>AutoStartServlet</servlet-name> <url-pattern>/auto.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>ThreadSafeServlet</servlet-name> <servlet-class>com.example.demo.ThreadSafeServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>ThreadSafeServlet</servlet-name> <url-pattern>/Safe.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>FileUploadServlet</servlet-name> <servlet-class>com.example.demo.FileUploadServlet</servlet-class> <multipart-config> <file-size-threshold>2000</file-size-threshold> </multipart-config> </servlet> <servlet-mapping> <servlet-name>FileUploadServlet</servlet-name> <url-pattern>/fileupload.do</url-pattern> </servlet-mapping> </web-app>
package com.example.demo; import javax.servlet.ServletContext; 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.Part; import java.io.IOException; import java.io.PrintWriter; import java.util.UUID; public class FileUploadServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { req.setCharacterEncoding("utf-8"); String desc = req.getParameter("desc"); Part part=req.getPart("file"); // InputStream inputStream = part.getInputStream(); String filename= UUID.randomUUID().toString()+part.getSubmittedFileName().substring(part.getSubmittedFileName().lastIndexOf(".")); ServletContext servletContext = this.getServletContext(); String realPath = servletContext.getRealPath("image"+filename); part.write(realPath); PrintWriter out=resp.getWriter(); out .println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">"); out.println("<HTML>"); out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>"); out.println(" <BODY>"); out.println("上传成功"); out.println("</BODY>"); out.println("</HTML>"); out.flush(); out.close(); } }
老师，这节课也是和上节课一样的问题，成功初始化servlet后，并没有出现value1和value2，访问页面也是404报错，老师能不能帮忙看看哪里出问题了
package com.example.demo; import jakarta.servlet.ServletConfig; import jakarta.servlet.ServletException; import jakarta.servlet.http.HttpServlet; import jakarta.servlet.http.HttpServletRequest; import jakarta.servlet.http.HttpServletResponse; import javax.servlet.annotation.WebInitParam; import javax.servlet.annotation.WebServlet; import java.io.IOException; import java.io.PrintWriter; @WebServlet(urlPatterns="/initParam.do" ,initParams ={@WebInitParam(name="key1",value="value1"),@WebInitParam(name="key2",value = "value2")} ,loadOnStartup = 1) public class InitParamServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { ServletConfig servletConfig = this.getServletConfig(); PrintWriter out=resp.getWriter(); out .println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">"); out.println("<HTML>"); out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>"); out.println(" <BODY>"); out.println("Value1"+servletConfig.getInitParameter("key1")+"<br/>"); out.println("Value2"+servletConfig.getInitParameter("key2")+"<br/>"); out.println("</BODY>"); out.println("</HTML>"); out.flush(); out.close(); } @Override public void init() throws ServletException { ServletConfig servletConfig = this.getServletConfig(); System.out.println(servletConfig.getInitParameter("key1")); System.out.println(servletConfig.getInitParameter("key2")); } }
我用注解无法获取响应页面，老师能帮忙看看是咋回事吗
package com.example.demo; import jakarta.servlet.ServletException; import jakarta.servlet.http.HttpServlet; import jakarta.servlet.http.HttpServletRequest; import jakarta.servlet.http.HttpServletResponse; import javax.servlet.annotation.WebServlet; import java.io.IOException; import java.io.PrintWriter; @WebServlet(urlPatterns = "/ann.do") public class AnnotationServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { PrintWriter out=resp.getWriter(); out .println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">"); out.println("<HTML>"); out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>"); out.println(" <BODY>"); out.println("Annotation servlet"); out.println("</BODY>"); out.println("</HTML>"); out.flush(); out.close(); } }
老师，访问index.jsp会调用getSession对象那里还是有疑问，在调用index.jsp时返回Session那块（和我们写的创建session的代码有关吗，还是Tomcat默认的行为，如果是默认的，那这种调用有什么用呀）
1.getCookie会将服务器端给予客户端的所有Cookie对象返回（不同域名下的一并返回）这样理解是对的吗
2.getCookie方法是不是通过ip地址和端口号实现区分不同客户端呀
<context-param>标签有啥用法呀，为啥该方法可以读取 web.xml 文件中<context-param>标签中的配置信息，但是不读取servlet标签信息，目前还不太了解<context-param>的用途
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