问答系统

使用了SSM框架搭建仿知乎问答社区

一.项目的来源

本项目对于一个本菜鸡来说是全新的技术栈，第一遍跟着做，做完后进行总结。争取今年五六月份进行项目的二次重构，并进行功能的扩展和完善。

二.项目环境搭建

• 操作系统:Windows 10
• IDE:IntelliJ IDEA 2018.3
• JDK Version : JDK1.8 建议使用JDK1.7以上版本
• Web容器 ： SpringBoot集成的默认容器-Tomcat
• 数据库 ：Mysql-8.0.13
• 依赖管理工具 : Maven 管理jar包真的很方便
• 版本控制: Git

三.项目的运行

• 下载

直接Download Zip或者是git clone

`git clone https://github.com/Howie66/wenda.git`

• 导入到IDE

使用IDEA创建的项目,配置好maven的相关配置,以及项目JDK版本,直接在主界面选择Open,然后找到项目所在路径,点击导入就可以了

• 邮件发送配置

    mailSender.setUsername("15615833117@163.com"); //账号的名字mailSender.setPassword("xxxxxx");//账号生成的动态密码mailSender.setHost("smtp.163.com");//使用的邮件服务器//mailSender.setHost("smtp.qq.com");mailSender.setPort(465);//邮件的端口mailSender.setProtocol("smtps");//邮件的协议mailSender.setDefaultEncoding("utf8");//邮件使用的编码
  

• 数据库的建立

数据库文件都在resourses/sql目录下面，导入数据库之后可以自行填充数据

三.项目问题总结

1.启动的时候报错显示无法注入（AutoWired）

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'initDatabaseTests': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.howie.wenda.dao.UserDAO com.howie.wenda.InitDatabaseTests.userDAO; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.howie.wenda.dao.UserDAO] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:839) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) ~[spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) ~[spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) ~[spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]at org.springframework.boot.test.SpringApplicationContextLoader.loadContext(SpringApplicationContextLoader.java:98) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:117) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:228) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:230) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.12.jar:4.12]at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:249) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) [junit-4.12.jar:4.12]at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) [junit-4.12.jar:4.12]at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) [junit-4.12.jar:4.12]at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) [junit-4.12.jar:4.12]at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) [junit-4.12.jar:4.12]at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.junit.runners.ParentRunner.run(ParentRunner.java:363) [junit-4.12.jar:4.12]at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:193) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.junit.runner.JUnitCore.run(JUnitCore.java:137) [junit-4.12.jar:4.12]at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68) [junit-rt.jar:na]at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47) [junit-rt.jar:na]at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242) [junit-rt.jar:na]at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70) [junit-rt.jar:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.howie.wenda.dao.UserDAO com.howie.wenda.InitDatabaseTests.userDAO; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.howie.wenda.dao.UserDAO] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:573) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]... 40 common frames omitted
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.howie.wenda.dao.UserDAO] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1373) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1119) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1014) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:545) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]... 42 common frames omitted2019-01-06 20:09:12.377  INFO 219244 --- [           main] .b.l.ClasspathLoggingApplicationListener : Application failed to start with classpath: unknown
2019-01-06 20:09:12.378 ERROR 219244 --- [           main] o.s.test.context.TestContextManager      : Caught exception while allowing TestExecutionListener [org.springframework.test.context.support.DependencyInjectionTestExecutionListener@815b41f] to prepare test instance [com.howie.wenda.InitDatabaseTests@37ceb1df]java.lang.IllegalStateException: Failed to load ApplicationContextat org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124) ~[spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83) ~[spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:117) ~[spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83) ~[spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:228) ~[spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:230) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.12.jar:4.12]at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:249) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) [junit-4.12.jar:4.12]at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) [junit-4.12.jar:4.12]at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) [junit-4.12.jar:4.12]at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) [junit-4.12.jar:4.12]at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) [junit-4.12.jar:4.12]at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.junit.runners.ParentRunner.run(ParentRunner.java:363) [junit-4.12.jar:4.12]at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:193) [spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.junit.runner.JUnitCore.run(JUnitCore.java:137) [junit-4.12.jar:4.12]at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68) [junit-rt.jar:na]at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47) [junit-rt.jar:na]at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242) [junit-rt.jar:na]at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70) [junit-rt.jar:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'initDatabaseTests': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.howie.wenda.dao.UserDAO com.howie.wenda.InitDatabaseTests.userDAO; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.howie.wenda.dao.UserDAO] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:839) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) ~[spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) ~[spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) ~[spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]at org.springframework.boot.test.SpringApplicationContextLoader.loadContext(SpringApplicationContextLoader.java:98) ~[spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98) ~[spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116) ~[spring-test-4.2.6.RELEASE.jar:4.2.6.RELEASE]... 24 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.howie.wenda.dao.UserDAO com.howie.wenda.InitDatabaseTests.userDAO; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.howie.wenda.dao.UserDAO] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:573) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]... 40 common frames omitted
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.howie.wenda.dao.UserDAO] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1373) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1119) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1014) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:545) ~[spring-beans-4.2.6.RELEASE.jar:4.2.6.RELEASE]... 42 common frames omittedjava.lang.IllegalStateException: Failed to load ApplicationContextat org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124)at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83)at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:117)at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83)at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:228)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:230)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:249)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89)at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)at org.junit.runners.ParentRunner.run(ParentRunner.java:363)at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:193)at org.junit.runner.JUnitCore.run(JUnitCore.java:137)at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'initDatabaseTests': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.howie.wenda.dao.UserDAO com.howie.wenda.InitDatabaseTests.userDAO; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.howie.wenda.dao.UserDAO] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772)at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:839)at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538)at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766)at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361)at org.springframework.boot.SpringApplication.run(SpringApplication.java:307)at org.springframework.boot.test.SpringApplicationContextLoader.loadContext(SpringApplicationContextLoader.java:98)at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98)at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116)... 24 more
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.howie.wenda.dao.UserDAO com.howie.wenda.InitDatabaseTests.userDAO; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.howie.wenda.dao.UserDAO] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:573)at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331)... 40 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.howie.wenda.dao.UserDAO] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1373)at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1119)at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1014)at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:545)... 42 more

解决方法: 这里我是改了一下注解的方式，手动指定bean

@Autowired(required=false)
@Qualifier("questionService")
@QuestionService questionService;

然后在DAO层的注解中改变了如下代码：

@Mapper
@Component
@Repository

2.Mybatis中报 java.lang.NullPointerException

解决方式：将数据库、表、字段的字符编码都应该统一，最好设置成utf8-general_ci

五.项目中的技术点讲解

• Velocity引擎

Velocity的出现主要是为了解决用户 界面与业务数据分离的情况，jsp在用户访问量大的时候容易出现解析时间久，用户体验性不好等等结果

• Velocity和Jsp的区别：

JSP文件实际上执行的是JSP对应的Java类，简单来说就是把JSP的HTML转化为out.write输出，而JSP中的Java代码直接复制到翻译后的Java类中，最终执行的是饭以后的Java类，而Velocity是按照语法规则解析成一颗语法树，然后执行这颗语法树来渲染结果。所以说：

1. 执行的方式不一样，JSP是编译执行，而Velocity是解释执行。如果JSP文件被修改了，那么对应的Java类也要重新编译，而Velocity不需要，因为只是重新的生成一颗语法树就行。
2. 执行效率不同。Jsp为方法调用直接执行，而Velovity是调用反射执行的，但是如果Jsp中有JSTL,语法标签的执行要看标签的实现复杂度。
3. 需要的编译环境不同：JSP需要Sevlet的环境而Velocity可以直接渲染

.

• Spring Boot

貌似最近Spring Boot挺火的,还跟微服务,SpringCould等高大上名词的扯上了关系.总结起来就是Spring的发展导致便携性非常高,然后各种配置文件很繁琐,于是又回到了注解的开发,大幅度减少无关于业务的代码量.这个倒确实有点体会,各种Spring的配置文件手动编写起来很是麻烦.

• 总结出特点就是:
• 创建独立的Spring应用程序
• 嵌入的Tomcat，无需部署WAR文件
• 简化Maven配置
• 自动配置Spring
• 提供生产就绪型功能，如指标，健康检查和外部配置
• 绝对没有代码生成和对XML没有要求配置

官方网站（可以直接创建工程并导入）

• 登录与注册

  • 引入了ticket的概念，用户登录之后会自动的产生一个ticket，然后又放到数据库中，ticket是具有时效性的，通过保存的过期时间与当前服务器的时间进行对比，如果过期了就要重新的登录。如果没有就直接是登录的状态，这里的ticket在服务器发送给客户端之后保存在Cooike中。
  • 用户登录注册功能主要实现的是用户的添加，验证和记住密码一段时间内的免密码登陆。用户的注册时往数据库中插入用户的用户名和密码等信息，用户的验证是从数据库中取出用户的用户名和密码进行比对。明文存储密码的风险性很大，所以采用的是在密码之后加salt再经过MD5加密的形式存储，这样一方面避免了用户密码信息泄露的风险，同时也防止了暴力破解密码的可能性。

• 敏感词过滤

我们采用的是用前缀树算法来进行匹配并替换，时间复杂度和空间复杂度可以降到O(k)

• 前缀树

• 根节点不包含字符,除根节点外每一个节点都只包含一个字符

• 从根节点到某一节点,路径上经过的字符连接起来,为该节点对应的字符串

• 每个节点的所有子节点包含的字符都不相同

• 在当今互联网这种上网人群多,访问量大的情况下,异步编程提供了一个非堵塞的,基于事件驱动的编程模型.这种编程方式可以充分利用计算机的多核来同时执行并行任务,提高资源的利用效率.应用场景在我了解的也不多,可以想象应用场景是很广泛的.举个很简单的例子,我们在网站注册新的社交账号的话,严格一点的网站都是会有验证邮箱地址的邮件.这个就是一个异步的事件,你不可能说直接把邮件验证的流程嵌套在业务逻辑里面.应该是把这个事件发送给一个队列里面,然后队列专门处理这种事件.在一个网站中有各种各样的事情需要进行处理

简单设计流程:

• 首先定义一个定义一个枚举类型的EventType类,这里面列举各种各样将会出现的事件
• 再定义一个事件模型EventModel类,里面包含的是一个事件所应该具有的一些属性.例如事件类型,操作者的ID,操作的实体类型,操作的实体ID,操作的实体拥有者等等
• 再定义一个接口EventHandler,里面写上几个抽象的方法,具体的实现由继承的类进行实现
• 定义一个事件生产者EventProducer,这里就是用来生产各种各样的事件,如异常登录或者是注册邮件等等.本项目中这里就是把事件送到Redis中进行储存
• 定义一个事件消费者EventConsumer,这里就是需要继承InitializingBean跟ApplicationContextAware.继承InitializingBean是可以定义bean的初始化方式,继承InitializingBean是为了可以通过这个上下文对象得到我们想获取的bean.然后在这个类里面使用多线程一直去Redis里面读取出事件,然后进行处理
• 再继承EventHandler在方法里面写自己的实现

代码示例：

• EventType类

    public enum EventType {LIKE(0),COMMENT(1),LOGIN(2),MAIL(3),FOLLOW(4),UNFOLLOW(5);private int value;EventType(int value) {this.value = value;}public int getValue() {return value;}}
  

• EventModel类

  public class EventModel {

    private EventType type;private int actorId;private int entityType;private int entityId;private int entityOwnerId;private Map<String, String> exts = new HashMap<>();public EventModel() {}public EventModel setExt(String key, String value) {exts.put(key, value);return this;}public EventModel(EventType type) {this.type = type;}public String getExt(String key) {return exts.get(key);}public EventType getType() {return type;}public EventModel setType(EventType type) {this.type = type;return this;}public int getActorId() {return actorId;}public EventModel setActorId(int actorId) {this.actorId = actorId;return this;}public int getEntityType() {return entityType;}public EventModel setEntityType(int entityType) {this.entityType = entityType;return this;}public int getEntityId() {return entityId;}public EventModel setEntityId(int entityId) {this.entityId = entityId;return this;}public int getEntityOwnerId() {return entityOwnerId;}public EventModel setEntityOwnerId(int entityOwnerId) {this.entityOwnerId = entityOwnerId;return this;}public Map<String, String> getExts() {return exts;}public EventModel setExts(Map<String, String> exts) {this.exts = exts;return this;}
  

  }

• EventHandler接口

    public interface EventHandler {void doHandle(EventModel model);List<EventType> getSupportEventTypes();}
  

• EventProducer类

    public class EventProducer {private final JedisAdapter jedisAdapter;@Autowiredpublic EventProducer(JedisAdapter jedisAdapter) {this.jedisAdapter = jedisAdapter;}public boolean fireEvent(EventModel eventModel) {try {String json = JSONObject.toJSONString(eventModel);String key = RedisKeyUtil.getEventQueueKey();jedisAdapter.lpush(key, json);return true;} catch (Exception e) {return false;}}}
  

• EventConsumer类

  public class EventConsumer implements InitializingBean, ApplicationContextAware {

    private static Logger logger = LoggerFactory.getLogger(EventConsumer.class);private Map<EventType, List<EventHandler>> config = new HashMap<>();private ApplicationContext applicationContext;private final JedisAdapter jedisAdapter;@Autowiredpublic EventConsumer(JedisAdapter jedisAdapter) {this.jedisAdapter = jedisAdapter;}@Overridepublic void afterPropertiesSet() throws Exception {Map<String, EventHandler> beans = applicationContext.getBeansOfType(EventHandler.class);if (beans != null) {for (Map.Entry<String, EventHandler> entry : beans.entrySet()) {List<EventType> eventTypes = entry.getValue().getSupportEventTypes();for (EventType type : eventTypes) {if (!config.containsKey(type)) {config.put(type, new ArrayList<>());}config.get(type).add(entry.getValue());}}}Thread thread = new Thread(new Runnable() {@Overridepublic void run() {while (true) {String key = RedisKeyUtil.getEventQueueKey();List<String> events = jedisAdapter.brpop(0, key);for (String message : events) {if (message.equals(key)) {continue;}EventModel eventModel = JSON.parseObject(message, EventModel.class);if (!config.containsKey(eventModel.getType())) {logger.error("不能识别的事件");continue;}for (EventHandler handler : config.get(eventModel.getType())) {handler.doHandle(eventModel);}}}}});thread.start();}@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {this.applicationContext = applicationContext;}
  

  }

• Handler继承类

  public class LikeHandler implements EventHandler {

    private final MessageService messageService;private final UserService userService;@Autowiredpublic LikeHandler(MessageService messageService, UserService userService) {this.messageService = messageService;this.userService = userService;}@Overridepublic void doHandle(EventModel model) {Message message = new Message();message.setFromId(WendaUtil.SYSTEM_USERID);message.setToId(model.getEntityOwnerId());message.setCreateDate(new Date());User user = userService.getUser(model.getActorId());message.setContent("用户" + user.getName() + "赞了你的评论,http://127.0.0.1:8080/question/" + model.getExt("questionId"));// 这里的会话ID肯定是系统管理员跟通知用户之间的会话message.setConversationId(WendaUtil.SYSTEM_USERID + "_" + model.getEntityOwnerId());messageService.addMessage(message);}@Overridepublic List<EventType> getSupportEventTypes() {return Arrays.asList(EventType.LIKE);}
  

  }

• Spring自定义bean的初始化方法

在写事件处理的时候继承了Spring的InitializingBean接口,这个接口只有一个方法:

public interface InitializingBean {/*** Invoked by a BeanFactory after it has set all bean properties supplied* (and satisfied BeanFactoryAware and ApplicationContextAware).* <p>This method allows the bean instance to perform initialization only* possible when all bean properties have been set and to throw an* exception in the event of misconfiguration.* @throws Exception in the event of misconfiguration (such* as failure to set an essential property) or if initialization fails.*/
void afterPropertiesSet() throws Exception;}

我们要对某个bean进行自定义的初始化的时候,我们就可以让bean继承这个接口,然后在里面写上我们的业务逻辑,在Spring初始化bean的时候就会检查bean是否继承了InitializingBean接口,然后再执行afterPropertiesSet()方法.

• Redis事务

在Java中使用Jedis操作事务

try {Transaction tx = jedis.multi();tx.zadd("test", 2, "1");tx.zadd("demo", 3, "2");List<Object> objs = tx.exec();tx.close();} catch (Exception e) {e.printStackTrace();} finally {
}

六.项目中小技术点

• 基本框架开发

  • 创建基本的Controller，service，model层。
  • controller层中使用注解进行配置，requestmapping，responsebody基本可以解决请求转发以及相应内容的渲染。responsebody自动选择viewresolver进行配置。
  • 使用pathvariable和requestparam传递参数
  • 使用velocity进行编写页面的模板，注意其中的语法使用。常用的是$!{}和${}
  • 使用http规范下的httpsevlerequest和httpsevletresponse来进行封装和相应，使用封装好的session和cookie对象
  • 使用重定向的redirectview和统一异常处理器exceptionhandler

• AOP和IOC

  • IOC解决对象实例化以及依赖传递问题，解耦
  • AOP解决纵向切面问题，主要实现日志和权限控制功能。
  • aspect实现切面，并且使用logger来记录日志，用该切面的切面方法来监听controller。

• 问题发表功能，并防止xss注入以及敏感词过滤

  • 发布问题的时候检查标题和内容，防止xss注入，并且过滤敏感词。
  • 防止xss注入直接使用HTMLutils的方法可以实现
  • 过滤敏感词首先需要简历一个字典树，并且读取一份保存敏感词的文本文件，然后初始化字典树。最后将过滤器作为一个服务，让需要过滤敏感词的服务进行调用

• 站内信

  • 两个用户之间发送一条消息，又一个唯一的会话id，在这个会话里面可以有多条交互信息，通过一个用户id获取该用户的会话列表，再根据会话id再获取具体的会话内的多条消息。

• 点赞和点踩的功能

  • 开发点赞和点踩的功能直接调用之前写好的jedis的增删改查，放在util包内。
  • 根据需求确定key字段，格式是like：实体类型：实体id和dislike：实体类型：实体id 这样可以将喜欢的人放在一个集合内，不喜欢的在一个集合内。
  • 点赞的操作是先修改redis的值并获取返回值，之后再异步修改mysql数据库的likecount数值。这样既可以保证点赞操作快速完成，也可以保证数据的一致性。

• 异步事件的功能

  • 在async包内开发异步工具包类，事件生产者，事件消费者，并且开发一个eventhandler接口，让各种事件的实现类来实现这个接口。
  • 事件生产者一般作为一个服务，由业务代码进行调用并产生一个事件。而事件消费者在代码中使用了单线程循环获取队列中的事件，并且寻找相应的handler进行处理。

• 邮件功能

  • 主要是引入mail依赖，并且配置好自己的邮箱信息，以及邮件模版，同时在业务代码中加入发邮件的逻辑就可以。

• 关注的功能，关注页面和粉丝页面

  • 主要是使用redis进行实现，通过crud操作可以对应的获取粉丝列表和关注列表，由于关注成功和粉丝成功时同一个事务中的两个操作，可以使用redis的事务multi来包装事务并进行操作。

七.项目中的重难点

八.项目可以完善的地方

• 用户注册，邮箱激活流程
• 首页滚动到底部自动加载更多
• 管理员后台管理(图形化的显示:进行数据分析与图形化显示)
• 运营推荐问题置顶
• timeline推拉结合
• 个性化首页，timeline更多事件
• 关键词过滤的优化算法
• 搜索结果排序打分
• 爬虫覆盖用户，评论，内容去html标签
• 个性化推荐(优化后的推荐算法)
• 分布式存储，数据库的分库分表
• 小程序进行同时显示
• 模版引擎优化为freemaker或者是Thymeleaf，替代掉Velocity
• 提高系统的并发量和准确率
• Ajax进行跨域传输(进行优化)
• 密码加密加强
• 争取使用Python中的框架进行二次开发
• 自定义拦截器(针对ip进行拦截)，限制单点登录
• 异步架构中增加更多的事件处理
• 支持多种邮件的发送
• 将前端转化为Vue或者是React等框架

九.课下需要做的功课