Question

我需要实现Spring的@Transactional注释，但我无法这样做。

过去3周我尝试了很多方法，但没有一种方法有效。

我还需要使用EntityManager。为了测试Spring是否正常工作，我尝试使用@PersistenceContext注入EntityManager（我也尝试使用@PersistenceUnit和/和EntityManagerFactory）但总是得到nullPointerException。

 @PersistenceContext(unitName = "sistema")
 protected EntityManager entityManager;

基本上我需要知道如何使spring的注释工作以及如何使用这些技术实现事务管理器：

persitence.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_2_0.xsd"
             version="2.0">
    <persistence-unit name="sistema" transaction-type="RESOURCE_LOCAL"> 
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <class>com.sis.vo.Person</class>

        <properties>
            <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />
            <property name="hibernate.connection.autocommit" value="false" />

            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>
            <property name="hibernate.enable_lazy_load_no_trans" value="false"/>
            <property name="hibernate.show_sql" value="false" />
            <property name="hibernate.format_sql" value="false"/>

            <!-- do I need those? -->
            <property name="hibernate.connection.url" value="jdbc:mysql://localhost/myDatabase?autoReconnect=true&amp;useSSL=false" />
            <property name="hibernate.connection.username" value="myUser" />
            <property name="hibernate.connection.password" value="myPass" />

        </properties>
   </persistence-unit>
</persistence>

spring.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:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:jee="http://www.springframework.org/schema/jee"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                    http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
                    http://www.springframework.org/schema/context
                    http://www.springframework.org/schema/context/spring-context-4.3.xsd
                    http://www.springframework.org/schema/mvc
                    http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd
                    http://www.springframework.org/schema/jee
                    http://www.springframework.org/schema/jee/spring-jee-4.3.xsd
                    http://www.springframework.org/schema/tx
                    http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">


    <context:annotation-config />
    <mvc:annotation-driven />

     <bean id="hikariConfig" class="com.zaxxer.hikari.HikariConfig">
        <property name="poolName" value="sisHikariCP" />
        <property name="connectionTestQuery" value="SELECT 1" />
        <property name="dataSourceClassName" value="com.mysql.jdbc.jdbc2.optional.MysqlDataSource" />
        <property name="minimumIdle" value="3" />
        <property name="maximumPoolSize" value="100" />
        <property name="idleTimeout" value="740000" />
        <property name="maxLifetime" value="1740000" />
        <property name="leakDetectionThreshold" value="30000" />
        <property name="dataSourceProperties">
            <props>
                <prop key="url">jdbc:mysql://localhost/myDatabase?autoReconnect=true&amp;useSSL=false</prop>
                <prop key="user">myUser</prop>
                <prop key="password">myPass</prop>

                <prop key="prepStmtCacheSize">350</prop>
                <prop key="prepStmtCacheSqlLimit">2048</prop>
                <prop key="cachePrepStmts">true</prop>
                <prop key="useServerPrepStmts">true</prop>
                <prop key="useLocalSessionState">true</prop>
                <prop key="useLocalTransactionState">true</prop>
                <prop key="rewriteBatchedStatements">true</prop>
                <prop key="cacheResultSetMetadata">true</prop>
                <prop key="cacheResultSetMetadata">true</prop>
                <prop key="cacheServerConfiguration">true</prop>
                <prop key="elideSetAutoCommits">true</prop>
                <prop key="maintainTimeStats">false</prop> 
            </props>
        </property>
    </bean>

    <bean id="dataSource" class="com.zaxxer.hikari.HikariDataSource" destroy-method="close">
        <constructor-arg ref="hikariConfig" />
    </bean>

    <bean id="myJpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />

    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="jpaVendorAdapter" ref="myJpaVendorAdapter" />

    </bean>

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>

    <tx:annotation-driven transaction-manager="transactionManager"  />


</beans>

的web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    id="WebApp_ID" version="3.0">
    <display-name>sis</display-name>

    <context-param>
        <param-name>javax.faces.INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL</param-name>
        <param-value>true</param-value>
    </context-param>
    <welcome-file-list>
        <welcome-file>index.jsf</welcome-file>
    </welcome-file-list>
    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>*.jsf</url-pattern>
    </servlet-mapping>


    <!--  SPRING  -->

    <servlet>
        <servlet-name>Spring Servlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
                <param-name>contextConfigLocation</param-name>
            <param-value>
                    /WEB-INF/spring.xml
            </param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
</web-app>

DAO

@Repository
public class GenericListDAO<E> {

    @PersistenceContext(unitName = "sistema")
    protected EntityManager entityManager;

    public EntityManager getEntityManager() {
        return entityManager;
    }

    public GenericListDAO() {
    }

    //rest of the code (persist, find, etc)
}

版本：

春季版：4.3.12
Hibernate版本：5.1.10.Final
HikariCP版本：2.7.3
JDK版本：1.8.0_121
Tomcat版本：8.5.23

谢谢！

Answer 1

这是我用来配置我的事务管理器

<bean id="myDatasource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
    <property name="driverClassName" value="${jdbc.driverClassName}"/>
    <property name="url" value="${jdbc.url}"/>
    <property name="username" value="${jdbc.username}"/>
    <property name="password" value="${jdbc.password}"/>
</bean>

<bean id="myJpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />

<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="dataSource" ref="myDatasource" />
    <property name="jpaVendorAdapter" ref="myJpaVendorAdapter" />

</bean>

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>

<tx:annotation-driven transaction-manager="transactionManager"  />

entityManagerFactory bean将使用类路径中的persistence.xml来创建持久性单元。

<强>更新得到你的持久性上下文

@PersistenceContext(unitName="sistema")
protected EntityManager em;

还要确保使用持久性上下文的类使用@Repository

进行注释

<强>更新你可以将它添加到web.xml

<!-- The definition of the Root Spring Container shared by all Servlets 
    and Filters -->
<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>
    classpath:/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>

现在在spring-root-context.xml旁边创建一个新文件spring.xml，并将所有与数据库和交易相关的内容移至spring-root-context.xml。

因此spring.xml将成为您的servlet上下文，spring-root-context.xml将成为您的根上下文。

与控制器相关的任何内容都将转到spring.xml所有其他bean将转到spring-root-context.xml

同时将<context:component-scan base-package="package.for.genericdao" />添加到spring.xml和spring-root-context.xml，并将package.for.genericdao替换为您的基本软件包名称。

如何使用Hibernate，HikariCP和persistence.xml实现Spring的@Transactional Annotation

1 个答案: