这个密码是什么呀？这个密码是什么呀？这个密码是什么呀？这个密码是什么呀？这个密码是什么呀？
老师我弄了好多次都是这样
这是我的数据库
webdemo.rar
老师有框架比如easyui、bootstrap这样的管理系统模板吗，自己写了一个easyui管理系统但是前端写的太糟糕了，增删改查全都写在一个html了，想看看别人是怎么写的
这块是怎么打开的呀 像这种问题能不能在视频里说一下怎么打开呀
为什么代码中new ArrayList和list是同一个呢？
package com.bjsxt.plane; import java.awt.*; /** * 游戏主窗口 */ public class MyGameFrame extends Frame { Image plane = GmaeUtil.getImage("images/plane.png"); Image bg = GmaeUtil.getImage("images/bg.jpg"); @Override public void paint(Graphics g) { g.drawImage(bg,0,0,500,500,null); g.drawImage(plane,100,100,33,22,null); } public static void main(String[] args) { Frame MyGameFrame = new Frame(); } }
为什么我的加载不出来图片呀 出不来小飞机和背景 也没有报错呀
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]
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这个密码是什么呀？这个密码是什么呀？这个密码是什么呀？这个密码是什么呀？这个密码是什么呀？
这块是怎么打开的呀 像这种问题能不能在视频里说一下怎么打开呀 
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？
京公网安备 11011402011233号