通过对象删除作为参数不起作用

Question

朋友们好，我关注的是Spring+Hibernate+JPA。 我正在尝试对我的数据库执行删除操作。

当我从控制器传递模型的对象并且按照以下方式进行操作时，这是行不通的

@Transactional(readOnly = false)
@Override
public void doDeleteCategory(Category deleteCategory) {
    try {
        entityManager.remove(deleteCategory);
    } catch (Exception exc) {
        logger.info(exc.getStackTrace().toString());
    }
}

但是当我再次检索相同的对象时，它的工作方式如下

@Transactional(readOnly = false)
@Override
public void doDeleteCategory(Category deleteCategory) {
    Category category = retrieveCategory(deleteCategory.getCategoryId());
    try {
        entityManager.remove(deleteCategory);
    } catch (Exception exc) {
        logger.info(exc.getStackTrace().toString());
    }
}

我很想知道为什么当我通过这两种方法都做同样的事情时创建和更新/合并工作完美时会发生这种情况。

这是堆栈跟踪：

org.apache.catalina.core.ApplicationContext log
INFO: Destroying Spring FrameworkServlet 'oltapp'
Nov 28, 2013 1:46:36 PM org.apache.catalina.core.ApplicationContext log
INFO: Closing Spring root WebApplicationContext
Nov 28, 2013 1:47:14 PM org.apache.catalina.core.ApplicationContext log
INFO: No Spring WebApplicationInitializer types detected on classpath
Nov 28, 2013 1:47:14 PM org.apache.catalina.core.ApplicationContext log
INFO: Initializing Spring root WebApplicationContext
Nov 28, 2013 1:47:25 PM org.apache.catalina.core.ApplicationContext log
INFO: Initializing Spring FrameworkServlet 'oltapp'
Nov 28, 2013 1:53:56 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [oltapp] in context with path [/oltapp] threw exception [Request processing failed; nested exception is org.springframework.transaction.TransactionSystemException: Could not commit JPA transaction; nested exception is javax.persistence.RollbackException: Transaction marked as rollbackOnly] with root cause
javax.persistence.RollbackException: Transaction marked as rollbackOnly
at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:72)
at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:512)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:754)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:723)
at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:392)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:120)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at com.sun.proxy.$Proxy263.doDeleteCategory(Unknown Source)
at co.softwarehouse.olt.service.category.CategoryServiceImpl.doDeleteCategory(CategoryServiceImpl.java:68)
at co.softwarehouse.olt.web.controller.CategoryController.deleteCategory(CategoryController.java:98)
at co.softwarehouse.olt.web.controller.CategoryController.processCategory(CategoryController.java:140)
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:601)
at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:219)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1008)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1852)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)

Answer 1

merge 的全部意义在于获取一个分离的实体并将其状态合并到一个附加的实体。显然，合并适用于分离的实体。

remove 的全部意义在于获取一个附加实体并将其删除，因此您需要一个附加实体来删除它。 The javadoc 主题很明确：

void 移除（java.lang.Object 实体）

删除实体实例。

投掷：

• IllegalArgumentException - 如果实例不是实体或分离实体

• TransactionRequiredException - 如果在 PersistenceContextType.TRANSACTION 类型的容器管理实体管理器上调用并且没有事务

（强调我的）