当我运行项目时，我得到一个IllegalArgumentException，问题是我自动连接了StudentService（它的一个类实现了IStudentService）。但是当我自动连接IStudentService时，问题就解决了。人们告诉我这样做，但他们不告诉我为什么。我想知道导致问题的原因。感谢任何答案：＆gt;
StudentController
@Controller
public class StudentController {
@Autowired
StudentService studentService;
@RequestMapping("get")
public String get(){
Student student = new Student();
student.setName("abc");
try {
studentService.save(student);
} catch (Exception e) {
e.printStackTrace();
}
return "somwhere";
}
}
StudentService
@Service
public class StudentService implements IStudentService{
@Autowired
IStudentDao studentDao;
public Student getStudent(String id) throws Exception {
return studentDao.query(id);
}
public List<Student> getAll() throws Exception{
return studentDao.queryAll();
}
@Transactional
public void save(Student student)throws Exception{
studentDao.save(student);
}
@Transactional
public void delete(Student student) throws Exception{
studentDao.delete(student);
}
}
IStudentService
public interface IStudentService {
public Student getStudent(String id) throws Exception;
public List<Student> getAll() throws Exception;
public void save(Student student)throws Exception;
public void delete(Student student) throws Exception;
}
堆栈跟踪
**Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'studentController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.gtis.service.StudentService com.gtis.controller.StudentController.studentService; nested exception is java.lang.IllegalArgumentException: Can not set com.gtis.service.StudentService field com.gtis.controller.StudentController.studentService to com.sun.proxy.$Proxy30
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1146)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:296)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:293)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:633)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:651)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:602)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:665)
at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:521)
at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:462)
at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
at javax.servlet.GenericServlet.init(GenericServlet.java:244)
at org.eclipse.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:595)
at org.eclipse.jetty.servlet.ServletHolder.initialize(ServletHolder.java:385)
at org.eclipse.jetty.servlet.ServletHandler.initialize(ServletHandler.java:862)
at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:300)
at org.eclipse.jetty.webapp.WebAppContext.startWebapp(WebAppContext.java:1341)
at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1334)
at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:744)
at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:497)
at org.eclipse.jetty.maven.plugin.JettyWebAppContext.doStart(JettyWebAppContext.java:281)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:132)
at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:114)
at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:60)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.doStart(ContextHandlerCollection.java:154)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:132)
at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:114)
at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:60)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:132)
at org.eclipse.jetty.server.Server.start(Server.java:357)
at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:114)
at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:60)
at org.eclipse.jetty.server.Server.doStart(Server.java:324)
at org.eclipse.jetty.maven.plugin.JettyServer.doStart(JettyServer.java:68)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at org.eclipse.jetty.maven.plugin.AbstractJettyMojo.startJetty(AbstractJettyMojo.java:564)
at org.eclipse.jetty.maven.plugin.AbstractJettyMojo.execute(AbstractJettyMojo.java:360)
at org.eclipse.jetty.maven.plugin.JettyRunWarExplodedMojo.execute(JettyRunWarExplodedMojo.java:73)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
at org.codehaus.classworlds.Launcher.main(Launcher.java:47)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.gtis.service.StudentService com.gtis.controller.StudentController.studentService; nested exception is java.lang.IllegalArgumentException: Can not set com.gtis.service.StudentService field com.gtis.controller.StudentController.studentService to com.sun.proxy.$Proxy30
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:517)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:286)
... 68 more
Caused by: java.lang.IllegalArgumentException: Can not set com.gtis.service.StudentService field com.gtis.controller.StudentController.studentService to com.sun.proxy.$Proxy30
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:164)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:168)
at sun.reflect.UnsafeObjectFieldAccessorImpl.set(UnsafeObjectFieldAccessorImpl.java:81)
at java.lang.reflect.Field.set(Field.java:741)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:513)
... 70 more
2016-03-30 11:34:58.126:WARN:/demo:main: unavailable
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'studentController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.gtis.service.StudentService com.gtis.controller.StudentController.studentService; nested exception is java.lang.IllegalArgumentException: Can not set com.gtis.service.StudentService field com.gtis.controller.StudentController.studentService to com.sun.proxy.$Proxy30
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1146)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:296)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:293)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:633)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:651)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:602)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:665)
at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:521)
at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:462)
at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
at javax.servlet.GenericServlet.init(GenericServlet.java:244)
at org.eclipse.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:595)
at org.eclipse.jetty.servlet.ServletHolder.initialize(ServletHolder.java:385)
at org.eclipse.jetty.servlet.ServletHandler.initialize(ServletHandler.java:862)
at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:300)
at org.eclipse.jetty.webapp.WebAppContext.startWebapp(WebAppContext.java:1341)
at org.eclipse.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1334)
at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:744)
at org.eclipse.jetty.webapp.WebAppContext.doStart(WebAppContext.java:497)
at org.eclipse.jetty.maven.plugin.JettyWebAppContext.doStart(JettyWebAppContext.java:281)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:132)
at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:114)
at org.eclipse.jetty.server.handler.AbstractHandler.doStart(AbstractHandler.java:60)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.doStart(ContextHandlerCollection.java:154)
at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:132)
at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:114)
at *
答案 0 :(得分：1)
Spring正在为你的bean创建一个代理来处理事务，因为你的业务方法有一个@Transactional注释。当你的StudentService类实现一个接口时Spring会创建一个基于JDK接口的代理而不是基于CGLIB类的代理。这意味着Spring创建一个实现IStudentService并委托给StudentService的新类.Spring现在管理并用于注入的bean不再是继承的StudentService，而是一个IStudentService的代理。如果你真的想注入StudentService，你可以指示Spring使用@EnableTransactionManagement代理类而不是接口（proxyTargetClass = true）
答案 1 :(得分：0)
如果我理解你，IStudentService就是一个界面。从您得到的错误中，我猜测您在应用程序上下文中将IStudentService接口注释为Spring bean，而不是具体的StudentService类。因此，当Spring试图找到一个自动装配的bean时，它没有看到StudentService类型的bean。
答案 2 :(得分：0)
正如您在评论中提到的，您正在使用事务注释，而<tx:annotation-driven/>标记位于您的应用程序上下文中，它意味着您的类实现了代理接口，因此Spring实际上创建了一个实现接口的新类对象但不能继承你的班级学生服务
因此，自动装配不适用于学生服务。