Java 在persistence.xml 中引用Tomcat JNDI 数据源
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referring Tomcat JNDI datasource in persistence.xml
提问by Rostislav Matl
in server.xml I've defined global resource (I'm using Tomcat 6):
在 server.xml 中我定义了全局资源（我使用的是Tomcat 6）：
<GlobalNamingResources>
<Resource name="jdbc/myds" auth="Container"
type="javax.sql.DataSource"
maxActive="10" maxIdle="3" maxWait="10000"
username="sa" password=""
driverClassName="org.h2.Driver"
url="jdbc:h2:~/.myds/data/db"
/>
</GlobalNamingResources>
I see in catalina.out that this is bound, so I suppose it's OK.
我在 catalina.out 中看到这是绑定的，所以我想这没问题。
In my web app I have the link to the datasource, I'm not sure it's OK:
在我的网络应用程序中，我有指向数据源的链接，但我不确定它是否正确：
<Context>
<ResourceLink global='jdbc/myds' name='jdbc/myds' type="javax.sql.Datasource"/>
</Context>
and in application there is persistence.xml:
在应用程序中有persistence.xml：
<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="oam" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<non-jta-data-source>jdbc/myds</non-jta-data-source>
<!-- class definitions here, nothing else -->
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect"/>
</properties>
</persistence-unit>
</persistence>
It should be OK, but most probably this or the ResourceLink definition is wrong because I'm getting:
应该没问题，但很可能这个或 ResourceLink 定义是错误的，因为我得到：
javax.naming.NameNotFoundException: Name jdbc is not bound in this Context
javax.naming.NameNotFoundException：名称 jdbc 在此上下文中未绑定
What's wrong and why this does not work?
出了什么问题，为什么这不起作用？
UPDATE:
更新：
I've tried to get the datasource directly:
我试图直接获取数据源：
public class WebAppListener implements ServletContextListener
{
// ServletContextListener interface - start
public void contextInitialized(ServletContextEvent sce)
{
try
{
Context initCtx = new InitialContext();
Context envCtx = (Context) initCtx.lookup("java:comp/env");
DataSource ds = (DataSource)
envCtx.lookup("jdbc/myds");
}
catch (NamingException ex)
{
System.out.println("!!!! Got NamingException:");
ex.printStackTrace(System.out);
}
}
public void contextDestroyed(ServletContextEvent sce) { }
}
my web.xml:
我的 web.xml：
<listener>
<display-name>Listener</display-name>
<listener-class>WebAppListener</listener-class>
</listener>
Still getting the same error although I see the datasource in JMX console when I connect to the Tomcat (Catalina - Datasource - javax.sql.Datasource = "jdbc/myds" : ObjectName = Catalina:type=DataSource,class=javax.sql.DataSource,name="jdbc/myds". )
尽管我在连接到 Tomcat 时在 JMX 控制台中看到数据源（Catalina - Datasource - javax.sql.Datasource = "jdbc/myds" : ObjectName = Catalina:type=DataSource,class=javax.sql.数据源，名称=“jdbc/myds”。）
回答by JoseK
The <non-jta-data-source>in persistence.xmlshould be
将<non-jta-data-source>在persistence.xml应
java:comp/env/jdbc/myds
java:comp/env/jdbc/myds
as per the response in http://forums.oracle.com/forums/thread.jspa?messageID=1899677
根据http://forums.oracle.com/forums/thread.jspa?messageID=1899677 中的响应
And also is your db driver in $CATALINA_HOME/lib
还有你的数据库驱动程序 $CATALINA_HOME/lib
回答by Pascal Thivent
Did you make that resource available for the application by declaring it in your web.xml?
您是否通过在您的web.xml?
<resource-ref>
<description>DB Connection</description>
<res-ref-name>jdbc/myds</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
回答by Whome
(Im using Apache OpenJPA library in Tomcat7 so may not match to Hibernate stuff)
（我在 Tomcat7 中使用 Apache OpenJPA 库，所以可能与 Hibernate 的东西不匹配）
I have never used a global jdbc for my OpenJPA webapps but gave it a try. It worked and this is my configuration. See folder where persistence.xml is saved, probably is openjpa problem but without it nothing works.
我从未在我的 OpenJPA 网络应用程序中使用过全局 jdbc，但尝试了一下。它有效，这是我的配置。查看保存persistence.xml 的文件夹，可能是openjpa 问题，但没有它就没有任何作用。
myapp/WEB-INF/classes/META-INF/persistence.xml
this is using openjpa provider so class list may not be needed in hibernate.
myapp/WEB-INF/classes/META-INF/persistence.xml
这是使用 openjpa 提供程序，因此在休眠中可能不需要类列表。
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<persistence-unit name="main" transaction-type="RESOURCE_LOCAL">
<provider>org.apache.openjpa.persistence.PersistenceProviderImpl</provider>
<non-jta-data-source>java:comp/env/jdbc/mydb</non-jta-data-source>
<class>com.myapp.db.User</class>
<class>com.myapp.db.Server</class>
<properties>
<property name="openjpa.DynamicEnhancementAgent" value="false" />
<property name="openjpa.RuntimeUnenhancedClasses" value="unsupported" />
<property name="openjpa.Log" value="commons" />
<property name="openjpa.ConnectionFactoryProperties" value="PrintParameters=true" />
</properties>
</persistence-unit>
</persistence>
tomcat/conf/server.xml
Add global jdbc resource.
tomcat/conf/server.xml
添加全局 jdbc 资源。
..cut...
<GlobalNamingResources>
<Resource name="UserDatabase" auth="Container"
type="org.apache.catalina.UserDatabase"
description="User database that can be updated and saved"
factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
pathname="conf/tomcat-users.xml" readonly="true" />
<Resource name="jdbc/mydb" auth="Container" type="javax.sql.DataSource"
maxActive="100" maxIdle="20" maxWait="10000"
username="myuser" password="mypwd"
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/mydb?useUnicode=true&characterEncoding=utf8"
validationQuery="SELECT 1" removeAbandoned="true" removeAbandonedTimeout="300"
/>
</GlobalNamingResources>
..cut...
tomcat/conf/Catalina/localhost/myapp.xml
this my development box so I use docBase to link directly to projects folder. You should be find inserting this to war package (META-INF/context.xml) when deployed to production box.
tomcat/conf/Catalina/localhost/myapp.xml
这是我的开发框，所以我使用 docBase 直接链接到项目文件夹。部署到生产框时，您应该会发现将其插入到 war 包 (META-INF/context.xml) 中。
<?xml version="1.0" encoding="UTF-8"?>
<Context docBase="/projects/myapp/web" reloadable="true" crossContext="true" >
<Realm className="org.apache.catalina.realm.DataSourceRealm"
dataSourceName="jdbc/mydb" localDataSource="false" digest="SHA"
userTable="user" userNameCol="username" userCredCol="password"
userRoleTable="user_role_v" roleNameCol="role"
/>
<ResourceLink name="jdbc/mydb" global="jdbc/mydb" type="javax.sql.DataSource" />
</Context>
myapp/WEB-INF/web.xml
Add resource-ref to the end of file.
myapp/WEB-INF/web.xml
将 resource-ref 添加到文件末尾。
<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app 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_3_0.xsd"
version="3.0" >
<description>Webapp</description>
<display-name>Webapp</display-name>
..cut...
<resource-ref>
<description>mydb</description>
<res-ref-name>jdbc/mydb</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
</web-app>
Because Im using OpenJPA+Tomcat7 (not fullsized j2ee container) this may look overengineering but thats how it works. Results are good and developing db-aware webapps is very easy. No need to manual sql query hardcoding and oldskool DAO classes.
因为我使用的是 OpenJPA+Tomcat7（不是全尺寸的 j2ee 容器），这可能看起来过度设计，但这就是它的工作原理。结果很好，开发 db-aware webapps 非常容易。无需手动 sql 查询硬编码和 oldskool DAO 类。
