Hibernate EntityManager没有被注入 - NullPointer [英] Hibernate EntityManager not being injected - NullPointer
本文介绍了Hibernate EntityManager没有被注入 - NullPointer的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我试图在Spring项目中使用Hibernate和JPA，但注入EntityManager时遇到问题。当我部署网站并打开它时，我的请求处理失败;嵌套异常是java.lang.NullPointerException，因为管理器始终为空。
这是我的配置文件：
pom.xml
<？xml version =1.0encoding =UTF-8？>
< project xmlns =http://maven.apache.org/POM/4.0.0xmlns：xsi =http://www.w3.org/2001/XMLSchema-instance
xsi：schemaLocation =http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd\">
< modelVersion> 4.0.0< / modelVersion>
< groupId> com.foo< / groupId>
< artifactId>工件< / artifactId>
<名称>名称< /名称>
<包装>战争< / packaging>
< version> 1.0.0-BUILD-SNAPSHOT< / version>
<属性>
< java-version> 1.6< / java-version>
< org.springframework-version> 3.2.2.RELEASE< /org.springframework-version>
< org.aspectj-version> 1.7.1< /org.aspectj-version>
< org.slf4j-version> 1.7.2< /org.slf4j-version>
< / properties>
<依赖关系>
<！ - Spring - >
< dependency>
< groupId> org.springframework< / groupId>
< artifactId> spring-context< / artifactId>
< version> $ {org.springframework-version}< / version>
<排除项>
<！ - 排除Commons记录SLF4j - >
<排除>
< groupId> commons-logging< / groupId>
< artifactId> commons-logging< / artifactId>
< /排除>
< /排除>
< /依赖关系>
< dependency>
< groupId> org.springframework< / groupId>
< artifactId> spring-webmvc< / artifactId>
< version> $ {org.springframework-version}< / version>
< /依赖关系>
<！ - AspectJ - >
< dependency>
< groupId> org.aspectj< / groupId>
< artifactId> aspectjrt< / artifactId>
< version> $ {org.aspectj-version}< / version>
< /依赖关系>
<！ - 数据库 - >
< dependency>
< groupId> mysql< / groupId>
< artifactId> mysql-connector-java< / artifactId>
< version> 5.1.24< / version>
< /依赖关系>
< dependency>
< groupId> org.hibernate< / groupId>
< artifactId> hibernate-entitymanager< / artifactId>
< version> 4.2.0.Final< / version>
< /依赖关系>
< dependency>
< groupId> org.hibernate.javax.persistence< / groupId>
< artifactId> hibernate-jpa-2.0-api< / artifactId>
< version> 1.0.1.Final< / version>
< /依赖关系>
< dependency>
< groupId> org.springframework< / groupId>
< artifactId> spring-orm< / artifactId>
< version> 3.2.0.RELEASE< / version>
<！ - 将带有所有需要的Spring依赖项，比如spring-core
和spring-beans->
< /依赖关系>
< dependency>
< groupId> org.hibernate< / groupId>
< artifactId> hibernate-entitymanager< / artifactId>
< version> 4.1.9.Final< / version>
<！ - 将随Hibernate核心提供 - >
< /依赖关系>
< dependency>
< groupId> commons-dbcp< / groupId>
< artifactId> commons-dbcp< / artifactId>
< version> 20030825.184428< / version>
< type> jar< / type>
< scope>编译< / scope>
< /依赖关系>
< dependency>
< groupId> commons-pool< / groupId>
< artifactId> commons-pool< / artifactId>
< version> 20030825.183949< / version>
< type> jar< / type>
< scope>编译< / scope>
< /依赖关系>
< dependency>
< groupId> commons-collections< / groupId>
< artifactId> commons-collections< / artifactId>
< version> 3.1< / version>
< /依赖关系>
<！ - - 记录 - >
< dependency>
< groupId> org.slf4j< / groupId>
< artifactId> slf4j-api< / artifactId>
< version> $ {org.slf4j-version}< / version>
< /依赖关系>
< dependency>
< groupId> org.slf4j< / groupId>
< artifactId> jcl-over-slf4j< / artifactId>
< version> $ {org.slf4j-version}< / version>
< scope>运行时< / scope>
< /依赖关系>
< dependency>
< groupId> org.slf4j< / groupId>
< artifactId> slf4j-log4j12< / artifactId>
< version> $ {org.slf4j-version}< / version>
< scope>运行时< / scope>
< /依赖关系>
< dependency>
< groupId> log4j< / groupId>
< artifactId> log4j< / artifactId>
< version> 1.2.17< / version>
<排除项>
<排除>
< groupId> javax.mail< / groupId>
< artifactId>邮件< / artifactId>
< /排除>
<排除>
< groupId> javax.jms< / groupId>
< artifactId> jms< / artifactId>
< /排除>
<排除>
< groupId> com.sun.jdmk< / groupId>
< artifactId> jmxtools< / artifactId>
< /排除>
<排除>
< groupId> com.sun.jmx< / groupId>
< artifactId> jmxri< / artifactId>
< /排除>
< /排除>
< scope>运行时< / scope>
< /依赖关系>
<！ - @Inject - >
< dependency>
< groupId> javax.inject< / groupId>
< artifactId> javax.inject< / artifactId>
< version> 1< / version>
< /依赖关系>
<！ - Servlet - >
< dependency>
< groupId> javax.servlet< / groupId>
< artifactId> servlet-api< / artifactId>
< version> 2.5< / version>
< scope>提供< / scope>
< /依赖关系>
< dependency>
< groupId> javax.servlet.jsp< / groupId>
< artifactId> jsp-api< / artifactId>
< version> 2.1< / version>
< scope>提供< / scope>
< /依赖关系>
< dependency>
< groupId> javax.servlet< / groupId>
< artifactId> jstl< / artifactId>
< version> 1.2< / version>
< /依赖关系>
<！ - Test - >
< dependency>
< groupId> junit< / groupId>
< artifactId> junit< / artifactId>
< version> 4.11< / version>
< scope> test< / scope>
< /依赖关系>
<！ - 验证 - >
< dependency>
< groupId> javax.validation< / groupId>
< artifactId> validation-api< / artifactId>
< version> 1.0.0.GA< / version>
< scope>编译< / scope>
< /依赖关系>
< dependency>
< groupId> org.hibernate< / groupId>
< artifactId> hibernate-validator< / artifactId>
< version> 4.0.0.GA< / version>
< scope>编译< / scope>
< /依赖关系>
< /依赖关系>
< build>
< finalName> ROOT< / finalName>
< plugins>
< plugin>
< artifactId> maven-eclipse-plugin< / artifactId>
< version> 2.9< / version>
<配置>
< additionalProjectnatures>
< projectnature> org.springframework.ide.eclipse.core.springnature< / projectnature>
< / additionalProjectnatures>
< additionalBuildcommands>
< buildcommand> org.springframework.ide.eclipse.core.springbuilder< / buildcommand>
< / additionalBuildcommands>
< downloadSources> true< / downloadSources>
< downloadJavadocs> true< / downloadJavadocs>
< / configuration>
< / plugin>
< plugin>
< groupId> org.apache.maven.plugins< / groupId>
< artifactId> maven-compiler-plugin< / artifactId>
< version> 2.5.1< / version>
<配置>
< source> 1.6< / source>
< target> 1.6< / target>
< compilerArgument> -Xlint：all< / compilerArgument>
< showWarnings> true< / showWarnings>
< showDeprecation> true< / showDeprecation>
< / configuration>
< / plugin>
< plugin>
< groupId> org.codehaus.mojo< / groupId>
< artifactId> exec-maven-plugin< / artifactId>
< version> 1.2.1< / version>
<配置>
< mainClass> org.test.int1.Main< / mainClass>
< / configuration>
< / plugin>
< / plugins>
< / build>
< / project>
<？xml version =1.0encoding =UTF-8？>
< web-app version =2.5xmlns =http://java.sun.com/xml/ns/javaee
xmlns：xsi =http：//www.w3。 org / 2001 / XMLSchema-instance
xsi：schemaLocation =http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web- app_2_5.xsd>
< display-name>显示名称< / display-name>
<！ - 所有Servlet和过滤器共享的Root Spring容器的定义 - >
< context-param>
< param-name> contextConfigLocation< / param-name>
< param-value> /WEB-INF/spring/root-context.xml< / param-value>
< / context-param>
<！ - 创建所有Servlet和过滤器共享的Spring容器 - >
< listener>
< listener-class> org.springframework.web.context.ContextLoaderListener< / listener-class>
< / listener>
<！ - 处理应用程序请求 - >
< servlet>
< servlet-name> appServlet< / servlet-name>
< servlet-class> org.springframework.web.servlet.DispatcherServlet< / servlet-class>
< init-param>
< param-name> contextConfigLocation< / param-name>
< param-value> /WEB-INF/spring/appServlet/servlet-context.xml< / param-value>
< / init-param>
1< / load-on-startup>
< / servlet>
< servlet-mapping>
< servlet-name> appServlet< / servlet-name>
< url-pattern> /< / url-pattern>
< / servlet-mapping>
< / web-app>
root-context.xml
<？xml version =1.0encoding =UTF-8？>
< beans xmlns =http://www.springframework.org/schema/beans
xmlns：xsi =http://www.w3.org/2001/XMLSchema-instancexmlns ：tx =http://www.springframework.org/schema/tx
xsi：schemaLocation =http://www.springframework.org/schema/beans http://www.springframework.org/ schema / beans / spring-beans.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd\">
<！ - 根上下文：定义对所有其他Web组件可见的共享资源 - >
< import resource =db.xml/>
< / beans>
db.xml
<？xml version =1.0encoding =UTF-8？>
< beans xmlns =http://www.springframework.org/schema/beans
xmlns：xsi =http://www.w3.org/2001/XMLSchema-instancexmlns ：mvc =http://www.springframework.org/schema/mvc
xmlns：context =http://www.springframework.org/schema/contextxmlns：tx =http：// www.springframework.org/schema/tx
xsi：schemaLocation =http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans- 3.0.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
http：// www .springframework.org / schema / context http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/tx http：// www.springframework.org/schema/tx/spring-tx.xsd
default-autowire =byName>
<！ - 在@Components的应用程序的基本包内扫描到
配置为bean - >
< bean id =placeholderConfig
class =org.springframework.beans.factory.config.PropertyPlaceholderConfigurer>
< property name =locationvalue =classpath：db.properties/>
< / bean>
< bean id =entityManagerFactory
class =org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean>
< property name =dataSourceref =dataSource/>
< property name =jpaVendorAdapter>
< bean class =org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter>
< property name =showSqlvalue =true/>
< property name =generateDdlvalue =true/>
< property name =databasePlatformvalue =$ {db.dialect}/>
< / bean>
< / property>
< / bean>
< bean id =dataSourceclass =org.apache.commons.dbcp.BasicDataSource
destroy-method =close>
< property name =driverClassNamevalue =$ {db.driver}/>
< property name =urlvalue =$ {db.url}/>
< property name =usernamevalue =$ {db.username}/>
< property name =passwordvalue =$ {db.password}/>
< / bean>
< bean id =transactionManagerclass =org.springframework.orm.jpa.JpaTransactionManager>
< property name =entityManagerFactoryref =entityManagerFactory/>
< / bean>
< tx：注解驱动的事务管理器=transactionManager/>
< bean
class =org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor/>
< / beans>
persistence.xml
<？xml version =1.0encoding =UTF-8？>
< persistence xmlns =http://java.sun.com/xml/ns/persistence
xmlns：xsi =http://www.w3.org/2001/XMLSchema-instance
xsi：schemaLocation =http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd
version =1.0>
< persistence-unit name =persistenceUnittransaction-type =RESOURCE_LOCAL>
< provider> org.hibernate.ejb.HibernatePersistence< / provider>
<属性>
< property name =hibernate.hbm2ddl.autovalue =create-drop/>
< property name =hibernate.show_sqlvalue =true/>
< property name =hibernate.transaction.flush_before_completion
value =true/>
< property name =hibernate.cache.provider_classvalue =org.hibernate.cache.HashtableCacheProvider/>
< / properties>
< / persistence-unit>
< /余辉>
db.properties
db.password = pass
db.username = user
db.url = jdbc：mysql：// url：3306 / dbname
db.dialect = org.hibernate .dialect.MySQLInnoDBDialect
db.driver = com.mysql.jdbc.Driver
TagServiceImpl。 java
@Repository
@Transactional
公共类TagServiceImpl实现TagService {
@PersistenceContext
私有EntityManager管理器;
@Override
@Transactional
公共列表< Tag> findAll（）{
List< Tag> tags = manager.creationQuery（从标签t中选择t）。getResultList（）; //在这里引发的异常
ModelAndView mav = new ModelAndView（tags）;
mav.addObject（tags，tags）;
返回标签;
$ / code> TagController.java
@Controller
公共类标记控制器{
$ b $ / **
*只需选择主视图来渲染返回它的名字。
* /
@RequestMapping（value =/，method = RequestMethod.GET）
public ModelAndView home（Locale locale）{
ModelAndView modelAndView = new ModelAndView（tags ）;
TagService tagService = new TagServiceImpl（）;
列表< Tag> tags = tagService.findAll（）;
modelAndView.addObject（tags，tags）;
返回modelAndView;
$ / code $ / pre
我对Spring很陌生，看看我做错了什么，所以我希望你能帮助我。我需要更多的信息。提前感谢您。 b
$ b < bean class =org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor/>
另请参阅：空指针异常实体管理器
I'm trying to use Hibernate and JPA in a Spring project but I have problems injecting the EntityManager. When I deploy the site and I open it, I get Request processing failed; nested exception is java.lang.NullPointerException because the manager is always null.
This are my config files:
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.foo</groupId>
<artifactId>artifact</artifactId>
<name>name</name>
<packaging>war</packaging>
<version>1.0.0-BUILD-SNAPSHOT</version>
<properties>
<java-version>1.6</java-version>
<org.springframework-version>3.2.2.RELEASE</org.springframework-version>
<org.aspectj-version>1.7.1</org.aspectj-version>
<org.slf4j-version>1.7.2</org.slf4j-version>
</properties>
<dependencies>
<!-- Spring -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${org.springframework-version}</version>
<exclusions>
<!-- Exclude Commons Logging in favor of SLF4j -->
<exclusion>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${org.springframework-version}</version>
</dependency>
<!-- AspectJ -->
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>${org.aspectj-version}</version>
</dependency>
<!-- Database -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.24</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>4.2.0.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate.javax.persistence</groupId>
<artifactId>hibernate-jpa-2.0-api</artifactId>
<version>1.0.1.Final</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>3.2.0.RELEASE</version>
<!-- will come with all needed Spring dependencies such as spring-core
and spring-beans -->
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>4.1.9.Final</version>
<!-- will come with Hibernate core -->
</dependency>
<dependency>
<groupId>commons-dbcp</groupId>
<artifactId>commons-dbcp</artifactId>
<version>20030825.184428</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>commons-pool</groupId>
<artifactId>commons-pool</artifactId>
<version>20030825.183949</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>commons-collections</groupId>
<artifactId>commons-collections</artifactId>
<version>3.1</version>
</dependency>
<!-- Logging -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${org.slf4j-version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>jcl-over-slf4j</artifactId>
<version>${org.slf4j-version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>${org.slf4j-version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
<exclusions>
<exclusion>
<groupId>javax.mail</groupId>
<artifactId>mail</artifactId>
</exclusion>
<exclusion>
<groupId>javax.jms</groupId>
<artifactId>jms</artifactId>
</exclusion>
<exclusion>
<groupId>com.sun.jdmk</groupId>
<artifactId>jmxtools</artifactId>
</exclusion>
<exclusion>
<groupId>com.sun.jmx</groupId>
<artifactId>jmxri</artifactId>
</exclusion>
</exclusions>
<scope>runtime</scope>
</dependency>
<!-- @Inject -->
<dependency>
<groupId>javax.inject</groupId>
<artifactId>javax.inject</artifactId>
<version>1</version>
</dependency>
<!-- Servlet -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.1</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!-- Test -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<!-- Validation -->
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>1.0.0.GA</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-validator</artifactId>
<version>4.0.0.GA</version>
<scope>compile</scope>
</dependency>
</dependencies>
<build>
<finalName>ROOT</finalName>
<plugins>
<plugin>
<artifactId>maven-eclipse-plugin</artifactId>
<version>2.9</version>
<configuration>
<additionalProjectnatures>
<projectnature>org.springframework.ide.eclipse.core.springnature</projectnature>
</additionalProjectnatures>
<additionalBuildcommands>
<buildcommand>org.springframework.ide.eclipse.core.springbuilder</buildcommand>
</additionalBuildcommands>
<downloadSources>true</downloadSources>
<downloadJavadocs>true</downloadJavadocs>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.5.1</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
<compilerArgument>-Xlint:all</compilerArgument>
<showWarnings>true</showWarnings>
<showDeprecation>true</showDeprecation>
</configuration>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.2.1</version>
<configuration>
<mainClass>org.test.int1.Main</mainClass>
</configuration>
</plugin>
</plugins>
</build>
</project>
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<display-name>Display name</display-name>
<!-- The definition of the Root Spring Container shared by all Servlets and Filters -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring/root-context.xml</param-value>
</context-param>
<!-- Creates the Spring Container shared by all Servlets and Filters -->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<!-- Processes application requests -->
<servlet>
<servlet-name>appServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring/appServlet/servlet-context.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>appServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
root-context.xml
<?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:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
<!-- Root Context: defines shared resources visible to all other web components -->
<import resource="db.xml" />
</beans>
db.xml
<?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:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"
default-autowire="byName">
<!-- Scans within the base package of the application for @Components to
configure as beans -->
<bean id="placeholderConfig"
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location" value="classpath:db.properties" />
</bean>
<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="showSql" value="true" />
<property name="generateDdl" value="true" />
<property name="databasePlatform" value="${db.dialect}" />
</bean>
</property>
</bean>
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<property name="driverClassName" value="${db.driver}" />
<property name="url" value="${db.url}" />
<property name="username" value="${db.username}" />
<property name="password" value="${db.password}" />
</bean>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
<bean
class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />
</beans>
persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
version="1.0">
<persistence-unit name="persistenceUnit" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<properties>
<property name="hibernate.hbm2ddl.auto" value="create-drop" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.transaction.flush_before_completion"
value="true" />
<property name="hibernate.cache.provider_class" value="org.hibernate.cache.HashtableCacheProvider" />
</properties>
</persistence-unit>
</persistence>
db.properties
db.password=pass
db.username=user
db.url=jdbc:mysql://url:3306/dbname
db.dialect=org.hibernate.dialect.MySQLInnoDBDialect
db.driver=com.mysql.jdbc.Driver
TagServiceImpl.java
@Repository
@Transactional
public class TagServiceImpl implements TagService {
@PersistenceContext
private EntityManager manager;
@Override
@Transactional
public List<Tag> findAll() {
List <Tag> tags = manager.creationQuery("select t from Tag t").getResultList(); // Exception raised here
ModelAndView mav = new ModelAndView("tags");
mav.addObject("tags", tags);
return tags;
}
}
TagController.java
@Controller
public class TagController {
/**
* Simply selects the home view to render by returning its name.
*/
@RequestMapping(value = "/", method = RequestMethod.GET)
public ModelAndView home(Locale locale) {
ModelAndView modelAndView = new ModelAndView("tags");
TagService tagService = new TagServiceImpl();
List<Tag> tags = tagService.findAll();
modelAndView.addObject("tags", tags);
return modelAndView;
}
}
I'm very new to Spring but I don't see what I'm doing wrong so I hope you could help me. I more info is needed just ask. Thank you in advance.
解决方案 This must be the week for this issue, add this to your Spring Config
<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />
See also: Null Pointer Exception Entity Manager
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