老师，用eclipse
Mybatis Generator 插件
生成不了，报错：
mavendemo.zip
老师你用eclipse看看能不能生成
老师我有个疑问 为啥视频老师在test做测试啊 那些代码直接写在main文件夹 也可以啊
老师，为什么会报错？我明明实例化了Book对象。
package com.bjsxt.dom4j; import org.dom4j.Attribute; import org.dom4j.Document; import org.dom4j.DocumentException; import org.dom4j.Element; import org.dom4j.io.SAXReader; import java.awt.print.Book; import java.io.File; import java.util.ArrayList; import java.util.Iterator; import java.util.List; public class TestDOM4J { public static void main(String[] args) throws DocumentException { //(1) 创建SAXReader对象 SAXReader reader = new SAXReader(); //(2) 调用read方法 Document doc = reader.read(new File("book.xml")); //(3) 获取根元素 Element root = doc.getRootElement(); //books //(4) 通过迭代器遍历直接节点 for (Iterator<Element> iteBook = root.elementIterator(); iteBook.hasNext();){ Element bookEle = iteBook.next(); //得到book的属性 for (Iterator<Attribute> iteAtt= bookEle.attributeIterator(); iteAtt.hasNext();){ Attribute att = iteAtt.next(); System.out.println(att.getName()+"\t"+att.getText()); } } System.out.println("----------------------------------------"); List<Book> bookList = new ArrayList<>(); for (Iterator<Element> iteBook=root.elementIterator();iteBook.hasNext();){ //创建一个Book对象 Book book = new Book(); Element bookEle = iteBook.next(); //得到每一个book //使用for循环继续遍历 for (Iterator<Element> subBookEle = bookEle.elementIterator();subBookEle.hasNext();){ //得到每一个子元素 Element subEle = subBookEle.next(); System.out.println(subEle.getName()+"\t"+subEle.getText()); /* * 分装成Book对象 * */ //获取节点的名称 String nodeName = subEle.getName(); //name,author,price //使用switch判断 switch (nodeName){ case "name": book.setName(subEle.getText()); break; case "author": book.setAuthor(subEle.getText()); break; case "price": book.setPrice(Double.parseDouble(subEle.getText())); break; } } //添加集合中 bookList.add(book); } //遍历集合 System.out.println("\n遍历集合-----------------------\n"); for (Book b: bookList){ System.out.println(b.getName()+"\t"+b.getAuthor()+"\t"+b.getPrice()); } } }
package com.bjsxt.entity; public class Book { //私有属性 private String name; private String author; private double price; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getAuthor() { return author; } public void setAuthor(String author) { this.author = author; } public double getPrice() { return price; } public void setPrice(double price) { this.price = price; } public Book() { } public Book(String name, String author, double price) { this.name = name; this.author = author; this.price = price; } }
package JAVA002;
public class MyInteger {
private int val;
private static MyInteger[] cache;
static {
for (int i=-128;i<=127; i++) {
cache[i+128]=MyInteger.valueOf(i);
}
public static MyInteger valueOf(int i) {
if (i>=-128&&i<=127) {
return cache[i+128];
return new MyInteger(i);
private MyInteger(int i) {
this.val=i;
public static void main(String[] args) {
MyInteger m=MyInteger.valueOf(200);
System.out.println(m);
为什么运行会报错？
PDF文档从9.1.3自定义泛型直接到 Collection接口,缺失了下图这部分的
一、问题
方式2 这种方法如果在两个包下面有一样名字的类，且两个包都取了别名咋办？
老师给的tomcat9是只支持Windows的吗？我用的Mac是不是要自己去官网下载？
启动两个springboot都正常，网页上一访问就出现这个错误了，能帮忙看下吗？
java.lang.IllegalArgumentException: Invoked method public abstract void jakarta.servlet.http.HttpSession.setAttribute(java.lang.String,java.lang.Object) is no accessor method! at org.springframework.data.projection.Accessor.<init>(Accessor.java:50) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.data.projection.MapAccessingMethodInterceptor.invoke(MapAccessingMethodInterceptor.java:55) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.data.projection.ProjectingMethodInterceptor.invoke(ProjectingMethodInterceptor.java:64) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.data.projection.ProxyProjectionFactory$TargetAwareMethodInterceptor.invoke(ProxyProjectionFactory.java:245) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:59) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at com.sun.proxy.$Proxy72.setAttribute(Unknown Source) ~[na:na] at com.lin.session.test.controller.WebController.setMsg(WebController.java:13) ~[classes/:na] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_261] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_261] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_261] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_261] at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:892) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1039) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882) ~[spring-webmvc-5.1.8.RELEASE.jar:5.1.8.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.21.jar:9.0.21] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.springframework.session.web.http.SessionRepositoryFilter.doFilterInternal(SessionRepositoryFilter.java:151) ~[spring-session-core-2.1.4.RELEASE.jar:2.1.4.RELEASE] at org.springframework.session.web.http.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:81) ~[spring-session-core-2.1.4.RELEASE.jar:2.1.4.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109) ~[spring-web-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) [tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:853) [tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1587) [tomcat-embed-core-9.0.21.jar:9.0.21] at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.21.jar:9.0.21] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_261] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_261] at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.21.jar:9.0.21] at java.lang.Thread.run(Thread.java:748) [na:1.8.0_261]
那个node安装在了c盘，然后这里显示没有脚本，应该怎么做呢？
这三个文件什么情况下才会有出现的？需要将前后台的那些软件都安装好才有？
前端的代码有吗？在哪里能找得到？还没有写前端代码，也可以一样跟着这个视频一步一步操作？
老师，这里终止为什么是0呢，还有步长是-1也不太懂
老师您好，我在用jupyter记笔记时，出现一个问题，就是del在各IDE上的运行结果不一样，就有点搞不懂他们都是什么意思了，您看看我下面理解的都对吗。
原码
#构造函数 class Person: def __del__(self): #一般不用写，系统自带 print("销毁对象：{0}".format(self)) p1 = Person() p2 = Person() del p2 print("程序结束")
pycharm
这个就是说p2用del删除，然后程序走完，把p1也释放了，程序结束。
jupyter notebook
第一运行
第二次运行
这个是不是就是第一次运行结束之后他没有打印出p1的删除，但他执行了，在第二次运行时，他把第一次运行，p1删除的结果打印出来了。
3.IDLE
ID
IDLE运行的结果始终是这样的，那其实他也是在运行结束后，把p1删了，只是他不会打印出来。
老师，请问，win7系统怎么查看是否开启了虚拟化呢
非常抱歉给您带来不好的体验！为了更深入的了解您的学习情况以及遇到的问题，您可以直接拨打投诉热线：
我们将在第一时间处理好您的问题！
关于
课程分类
百战程序员微信公众号
百战程序员微信小程序
©2014-2025百战汇智（北京）科技有限公司 All Rights Reserved 北京亦庄经济开发区科创十四街 赛蒂国际工业园网站维护：百战汇智（北京）科技有限公司 京公网安备 11011402011233号 京ICP备18060230号-3 营业执照 经营许可证：京B2-20212637
方式2 这种方法如果在两个包下面有一样名字的类，且两个包都取了别名咋办？
那个node安装在了c盘，然后这里显示没有脚本，应该怎么做呢？
这三个文件什么情况下才会有出现的？需要将前后台的那些软件都安装好才有？
ID
京公网安备 11011402011233号