2025年java muki_再次学习 java 类的编译

大家好，我是讯享网，很高兴认识大家。

做JAVA开发的都知道myeclipse，我们在myeclipse中新建一个类，然后保存，如何正常的话，那么在项目指定的目录(也就是项目的output目录)就会生成同名的class文件，

可是，我们都知道myeclipse中的类的编译的原理？

看起来很简单的东西，其实不搞清楚的话，也是会让自己吃大亏的！

所谓基础不牢固，是很难成长的。 ———— 很大可能只是在泥潭中沉沦，想想自己前几年的经历就知道了。

项目部署在虚拟机的 tomcat上， tomcat启动的时候出现了错误，

[ERROR] [08-15 18:46:17] net.jweb.listener.AppInitializerListener - 启动初始化异常：

java.lang.ClassCastException: org.springframework.beans.factory.BeanCreationException cannot be cast to org.springframework.web.cont

ext.WebApplicationContext

at net.jweb.listener.AppInitializerListener.contextInitialized(AppInitializerListener.java:91)

at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4206)

at org.apache.catalina.core.StandardContext.start(StandardContext.java:4705)

at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1057)

at org.apache.catalina.core.StandardHost.start(StandardHost.java:840)

at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1057)

at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463)

at org.apache.catalina.core.StandardService.start(StandardService.java:525)

at org.apache.catalina.core.StandardServer.start(StandardServer.java:754)

at org.apache.catalina.startup.Catalina.start(Catalina.java:595)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

at java.lang.reflect.Method.invoke(Method.java:597)

at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)

at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)

[ERROR] [08-15 18:50:25] org.springframework.web.context.ContextLoader - Context initialization failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'syncServiceImpl' defined in file [/usr/linka

pp/bin/tomcat-master/webapps/ROOT/WEB-INF/classes/net/jweb/services/impl/SyncServiceImpl.class]: Instantiation of bean failed; neste

d exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [net.jweb.services.impl.SyncSe

rviceImpl]: Constructor threw exception; nested exception is java.lang.Error: Unresolved compilation problems:

The import org.apache.http.client.fluent cannot be resolved

The import com.alibaba cannot be resolved

Request cannot be resolved to a type

Request cannot be resolved

Response cannot be resolved to a type

JSONObject cannot be resolved to a type

JSONObject cannot be resolved

Request cannot be resolved to a type

Request cannot be resolved

Response cannot be resolved to a type

JSONObject cannot be resolved to a type

JSONObject cannot be resolved

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanF

actory.java:883)

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBe

anFactory.java:839)

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFact

ory.java:440)

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.jav

a:409)

at java.security.AccessController.doPrivileged(Native Method)

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactor

y.java:380)

at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264)

at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)

at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261)

at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185)

at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)

at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:429)

at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:728)

at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:380)

at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:255)

at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:199)

at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:45)