EJB/Hibernate不访问MySQL数据库

Question

我正在尝试学习如何使用JavaEE/EJB和数据库持久性，我有一个基本的示例，其中我希望通过输入字段将字符串保存到数据库中，并读取已保存项的列表。

我在本地主机上安装了一个MySQL服务器(V5.7Community Edition)，我的测试服务器是Eclipse10.1.0(通过WildFly )。整个项目是一个包含Web和EJB子项目的EAR容器。

我使用的是容器管理的事务，据我所知，当一个方法被调用时，事务会自动创建，并在该方法退出时立即刷新/提交。

问题是，没有数据被写入到实际的数据库中。但是也不会抛出错误。我假设，实体管理器缓存所有假定的存储，并在select时直接读回它们，甚至不检查数据库。因此，当我重新启动服务器时，什么也没有留下。此外，当我直接查看mysql db时，也什么也没有(甚至在wildfly服务器运行时，直接在假定插入之后)。我也尝试过直接将一些行添加到db表中，但select也没有“看到”它们。

因此，在我看来，尽管数据库是在persistence.xml中配置的，但它甚至没有被访问。我尝试删除连接url/用户名/密码，但实际上没有区别，实体管理器仍然没有抛出错误，一切似乎都正常。那么，它到底在哪里保存数据，我必须更改什么才能让它访问提供的mysql数据库呢？

处理程序(在Web项目中)：

@ManagedBean(name = "handlerBean")
@SessionScoped
public class HandlerBean {

@EJB
private TodoWorkerBeanRemote worker;

private String input;

public void add() {
    if (input.compareTo("") != 0) {

        TodoBean item = new TodoBean();
        item.setText(input);
        worker.saveItem(item);

        input = "";
    }
}
...

会话Bean /事务容器(在EJB项目中)

@Stateless
@TransactionManagement(TransactionManagementType.CONTAINER)
public class TodoWorkerBean implements TodoWorkerBeanRemote {

@PersistenceContext(unitName = "EnterpriseTestEJB")
private EntityManager entityManager;

public TodoWorkerBean() {
}

@Override
@TransactionAttribute(TransactionAttributeType.REQUIRES_NEW) // does not help
public void saveItem(TodoBean item) {

    // entityManager.joinTransaction(); <- does not help
    entityManager.persist(item); // tried .merge() as well
    // entityManager.flush(); <-does not help
}
...

实体Bean (在EJB项目中)

@Entity
@Table(name = "todobean")
@NamedNativeQueries({
    @NamedNativeQuery(name = "TodoBean.getItems", query = "select * from todobean", resultClass = TodoBean.class),
    @NamedNativeQuery(name = "TodoBean.clearItems", query = "delete from todobean") })
public class TodoBean implements Serializable {

private Integer id;
private String text;
...

persistence.xml (也尝试过hibernate.cfg.xml，没有区别)

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1"
xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="EnterpriseTestEJB">
    <class>de.dianasalsa.ejb.TodoBean</class>
    <properties>

        <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />
        <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/feedback" /> // not used
        <property name="hibernate.connection.username" value="root" /> // not used
        <property name="hibernate.connection.password" value="root" /> // not used

        <property name="hibernate.show_sql" value="true" />
        <property name="hibernate.format_sql" value="true" />
        <property name="hibernate.use_sql_comments" value="true" />

        <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect" />
        <property name="hibernate.hbm2ddl.auto" value="update" /> // tried "create" as well

    </properties>

</persistence-unit>
</persistence>

日志：

....
15:42:59,602 INFO  [org.jboss.as.jpa] (ServerService Thread Pool -- 66) WFLYJPA0010: Starting Persistence Unit (phase 2 of 2) Service 'EnterpriseTest.ear/EnterpriseTestEJB.jar#EnterpriseTestEJB'
15:42:59,952 INFO  [org.jboss.as.clustering.infinispan] (ServerService Thread Pool -- 65) WFLYCLINF0002: Started client-mappings cache from ejb container
15:42:59,973 INFO  [org.hibernate.dialect.Dialect] (ServerService Thread Pool -- 66) HHH000400: Using dialect: org.hibernate.dialect.MySQL5Dialect
15:43:00,102 INFO  [org.hibernate.envers.boot.internal.EnversServiceImpl] (ServerService Thread Pool -- 66) Envers integration enabled? : true
15:43:00,101 INFO  [org.jboss.as.protocol] (management I/O-1) WFLYPRT0057:  cancelled task by interrupting thread Thread[management-handler-thread - 3,5,management-handler-thread]
15:43:00,604 INFO  [org.hibernate.tool.hbm2ddl.SchemaUpdate] (ServerService Thread Pool -- 66) HHH000228: Running hbm2ddl schema update
15:43:00,617 INFO  [org.hibernate.tool.schema.extract.internal.InformationExtractorJdbcDatabaseMetaDataImpl] (ServerService Thread Pool -- 66) HHH000262: Table not found: todobean
15:43:00,619 INFO  [org.hibernate.tool.schema.extract.internal.InformationExtractorJdbcDatabaseMetaDataImpl] (ServerService Thread Pool -- 66) HHH000262: Table not found: todobean
15:43:01,499 INFO  [javax.enterprise.resource.webcontainer.jsf.config] (ServerService Thread Pool -- 83) Mojarra 2.2.13.SP1 20160303-1204 für Kontext '/EnterpriseTestWeb' wird initialisiert.
15:43:02,379 INFO  [org.wildfly.extension.undertow] (ServerService Thread Pool -- 83) WFLYUT0021: Registered web context: /EnterpriseTestWeb
15:43:02,414 INFO  [org.jboss.as.server] (ServerService Thread Pool -- 34) WFLYSRV0010: Deployed "EnterpriseTest.ear" (runtime-name : "EnterpriseTest.ear")
15:43:02,515 INFO  [org.jboss.as] (Controller Boot Thread) WFLYSRV0060: Http management interface listening on http://127.0.0.1:9990/management
15:43:02,519 INFO  [org.jboss.as] (Controller Boot Thread) WFLYSRV0051: Admin console listening on http://127.0.0.1:9990
15:43:02,519 INFO  [org.jboss.as] (Controller Boot Thread) WFLYSRV0025: WildFly Full 10.1.0.Final (WildFly Core 2.2.0.Final) started in 9581ms - Started 879 of 1127 services (422 services are lazy, passive or on-demand)
15:43:18,799 INFO  [org.jboss.ejb.client] (default task-2) JBoss EJB Client version 2.1.4.Final
15:43:32,763 INFO  [stdout] (default task-3) Hibernate: 
15:43:32,763 INFO  [stdout] (default task-3)     /* insert de.dianasalsa.ejb.TodoBean
15:43:32,763 INFO  [stdout] (default task-3)         */ insert 
15:43:32,763 INFO  [stdout] (default task-3)         into
15:43:32,763 INFO  [stdout] (default task-3)             todobean
15:43:32,763 INFO  [stdout] (default task-3)             (text) 
15:43:32,763 INFO  [stdout] (default task-3)         values
15:43:32,764 INFO  [stdout] (default task-3)             (?)

15:43:32,786 INFO  [stdout] (default task-3) Hibernate: 
15:43:32,786 INFO  [stdout] (default task-3)     /* TodoBean.getItems */ select
15:43:32,786 INFO  [stdout] (default task-3)         * 
15:43:32,787 INFO  [stdout] (default task-3)     from
15:43:32,787 INFO  [stdout] (default task-3)         todobean

Answer 1

对不起，我的英语...

您需要配置一个名为"jta-data-source“的JNDI，并使用"hibernate.hbm2ddl.auto”创建新关系，如下例所示：

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1"
    xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
    <persistence-unit name="EnterpriseTestEJB"
        transaction-type="JTA">
        <jta-data-source>java:jboss/datasources/some-name</jta-data-source>
        <properties>
            <property name="hibernate.hbm2ddl.auto" value="create" />
            <property name="hibernate.show_sql" value="true" />
        </properties>
    </persistence-unit>
</persistence>

wildfly有一个"namesever“，你可以使用JNDI名称从你的注释中访问它，比如"@PersistenceContext”。

在Wildfly at selfe中，您必须使用该JNDI名称配置新的MySql连接。

对于MySql连接，下载jdbc driver并将其上传到WildFly。https://dev.mysql.com/downloads/connector/j/5.1.html

Inser MySqgl jdbc Driver

该连接将使用JNDI名称命名(java:jboss/datasources/some name )。

Add new MySql Connection (1)

Add new MySql Connection (2)

当您在Wildfly中运行您的程序时，该程序将在wildfly中查找您的MySql连接的JNDI名称。

如果你想看一个示例代码，我在这里有一个来自我的研究：https://gitlab.com/Java_Project/JavaEE2.0

我希望它能解决你的问题。