我在运行阶段遇到类路径错误.错误是
run:
[java] java.lang.NoClassDefFoundError: org/openqa/selenium/WebDriver
[java] at java.lang.Class.getDeclaredMethods0(Native Method)
[java] at java.lang.Class.privateGetDeclaredMethods(Unknown Source)
[java] at java.lang.Class.privateGetMethodRecursive(Unknown Source)
[java] at java.lang.Class.getMethod0(Unknown Source)
[java] at java.lang.Class.getMethod(Unknown Source)
[java] at sun.launcher.LauncherHelper.validateMainClass(Unknown Source)
[java] at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
[java] Caused by: java.lang.ClassNotFoundException: org.openqa.selenium.WebDriver
[java] at java.net.URLClassLoader.findClass(Unknown Source)
[java] at java.lang.ClassLoader.loadClass(Unknown Source)
[java] at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
[java] at java.lang.ClassLoader.loadClass(Unknown Source)
[java] ... 7 more
[java] Error: A JNI error has occurred, please check your installation and try again
[java] Exception in thread "main"
[java] Java Result: …这是我第一次使用Spring,我正在关注PluralSight的教程.运行第一个示例,我遇到标题中列出的错误.在我的控制台中,我收到这样的错误.我正在使用旧版本的依赖项来完成本课程.我已经确保密切关注这个教程,所以不确定我是否搞砸了某个地方或某些东西已被弃用.我正在使用http:// localhost:8080/FitnessTracker/greeting.html
SEVERE: Context initialization failed
java.lang.IllegalArgumentException
SEVERE: StandardWrapper.Throwable
java.lang.IllegalArgumentException
SEVERE: Allocate exception for servlet fitTrackerServlet
java.lang.IllegalArgumentException
HelloController.java
package com.pluralsight.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class HelloController {
@RequestMapping(value = "/greeting")
public String sayHello(Model model) {
model.addAttribute("greeting", "Hello World");
return "hello";
}
}
的servlet-config.xml中
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd">
<mvc:annotation-driven />
<context:component-scan base-package="com.pluralsight.controller" />
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
p:prefix="/WEB-INF/jsp/" p:suffix=".jsp"/>
</beans>
为hello.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%> …我认为double和float之间的区别是小数的精度.但是,我使用double和float会得到奇怪的结果,并且它们彼此之间并不相同.
第一段代码与float格式一起使用,产生正确的结果:
#include <stdio.h>
#define ABSOLUTE_VALUE(number) ( ((number) < 0) ? -(number) : (number) )
int main (void)
{
float number, absNumber;
printf ("What number do you want to check the absolute value for? : ");
scanf ("%f", &number);
absNumber = ABSOLUTE_VALUE(number);
printf ("The absolute value of %.2f is %.2f\n", number, absNumber);
return 0;
}
输出:
您想要检查绝对值的是多少？:-3
-3.00的绝对值为3.00
第二段代码与double格式一起使用会产生错误的结果:
#include <stdio.h>
#define ABSOLUTE_VALUE(number) ( ((number) < 0) ? -(number) : (number) )
int main (void)
{
double number, absNumber;
printf …这可能吗？通过列表迭代,当在每个循环中存储数据时,我不能将其实际类用作变量类型.
@using MyFirstWebApplication.Models.Student
@model IEnumerable<MyFirstWebApplication.Models.Student>
@{
ViewBag.Title = "Title";
}
<h2>This is a heading</h2>
@foreach (Student student in Model)
{
<h2>Student Name: @student.FirstName @student.LastName</h2>
}
只有当foreach循环中的变量类型为'var'时,代码才会编译
不知道这里是什么问题，但是当我尝试编译Java文件时无法识别Javac。我假设为此需要一个特殊的插件，或者我需要使用apache ANT，但不太确定。
光盘src
javac HelloWorld.java
'javac' is not recognized as an internal or external command,
operable program or batch file.
java HelloWorld
Error: Could not find or load main class HelloWorld
我想在我的机器上访问http:// localhost:8080/EventTracker/greeting.但是,我收到404错误.我正在关注PluralSight Spring MVC4简介教程,看起来我的代码与视频中的代码相匹配.我使用两个java文件WebConfig和WebAppInitializer来配置我的应用程序.我错过了什么吗？我想我已经逐行复制但仍然没有工作.
HelloController.java
@Controller
public class HelloController {
@RequestMapping(value="/greeting")
public String sayHello(Model model) {
model.addAttribute("greeting", "Hello World");
return "hello.jsp";
}
}
WebAppInitializer.java
public class WebAppInitializer implements WebApplicationInitializer{
@Override
public void onStartup(ServletContext servletContext) throws ServletException {
WebApplicationContext context = getContext();
servletContext.addListener(new ContextLoaderListener(context) );
ServletRegistration.Dynamic dispatcher = servletContext.addServlet("DispatcherServlet", new DispatcherServlet(context) );
dispatcher.setLoadOnStartup(1);
dispatcher.addMapping("*.html");
}
private WebApplicationContext getContext() {
AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
context.setConfigLocation("com.pluralsight.WebConfig");
return context;
}
}
WebConfig.java
@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.pluralsight")
public class WebConfig { …在PluralSight上阅读"Hibernate简介"教程.我有这个异常错误.完整的错误是:
Exception in thread "main" org.hibernate.MappingException: Unknown entity: com.simpleprogrammer.User
at org.hibernate.internal.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:776)
at org.hibernate.internal.SessionImpl.getEntityPersister(SessionImpl.java:1451)
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:100)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:192)
at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:38)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:177)
at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:32)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:73)
at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:678)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:670)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:665)
at com.simpleprogrammer.Program.main(Program.java:15)
不确定有什么问题.我创建了User.java pojo.我创建了一个与pojo匹配的表.我创建了映射,然后将映射添加到hibernate.cfg.xml文件中.但是,仍然得到错误.谁能帮我解决这个问题？
的hibernate.cfg.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory name="">
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.default_schema">protein_tracker</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<mapping class="com.simpleprogrammer.User" resource="com/simpleprogrammer/User.hbm.xml"/>
</session-factory>
</hibernate-configuration>
Program.java
public class Program {
public static void main(String[] args) {
System.out.println("Hello World!");
Session session …