弹簧环境简介＆amp; JPA

时间：2014-09-27 23:52:37

标签： java spring tomcat jpa spring-profiles

我想在Spring JSON API应用程序中实现环境配置文件，以处理多个环境，开发，测试和生产。我见过Unable to use JNDI DataSource provided by Tomcat in Spring?等例子。我此时只需要处理不同的数据库设置，但稍后我可能需要额外的bean配置，具体取决于环境。

我的persistence.xml目前看起来像这样。

<?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="BPPersistenceUnit" transaction-type="RESOURCE_LOCAL">

        <!-- JNDI datasource -->
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <non-jta-data-source>java:comp/env/jdbc/BloodPressureDB</non-jta-data-source>

        <!-- Hibernate Settings -->
        <properties>

            <!-- java persistence settings -->
            <property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver" />
            <property name="javax.persistence.jdbc.url" value="jdbc:postgresql://127.0.0.1:5432/jkratz" />
            <property name="javax.persistence.jdbc.user" value="tomcat" />
            <property name="javax.persistence.jdbc.password" value="t0mc@t2014" />

            <!-- hibernate settings -->
            <property name="hibernate.show_sql" value="true" />
            <property name="hibernate.format_sql" value="true" />
            <property name="hibernate.connection.charSet" value="UTF-8" />
            <property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQL9Dialect" />
            <property name="hibernate.hbm2ddl.auto" value="validate" />

        </properties>

    </persistence-unit>
</persistence>

我已经看过不同的例子，所以我对如何实施有点困惑。

  1. 您仍然可以使用Tomcat数据源配置吗？如果是这样，它如何知道使用哪个配置文件？

  2. 如何为多个环境配置persistence.xml？ jdbc连接道具甚至应该在persistence.xml中

  3. 如何在不重新编译的情况下设置活动配置文件？

2 个答案:

答案 0 :(得分：2)

1。你还能使用Tomcat数据源配置吗？如果是这样，它如何知道使用哪个配置文件？

您可以使用Tomcat数据库配置，但数据源定义与Spring或Spring配置文件无关。如果您正在使用JNDI方法，那么您可能已定义了多个数据源，并且可以通过配置文件属性指定您在应用程序中使用的数据源，但实际定义与Spring无关。

或者，您可以使用非JNDI数据源，即在Spring中配置，也许使用配置文件。

2。如何为多个环境配置persistence.xml？ jdbc连接道具甚至应该在persistence.xml中

不，您在使用Spring时可能只需要一个最小的persistence.xml，或者根本不需要。

3。如何在不重新编译的情况下设置活动配置文件？

你不能

以下是启动和运行非JNDI数据源所需的全部内容。

Spring配置示例（非JNDI）： 

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:jpa="http://www.springframework.org/schema/data/jpa" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd http://www.springframework.org/schema/context 
          http://www.springframework.org/schema/context/spring-context-3.2.xsd">

    <jpa:repositories base-package="uk.co.certait.spring.data.repository" />

    <bean id="entityManagerFactory"
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="jpaVendorAdapter" ref="jpaAdapter"></property>
        <property name="persistenceUnitName" value="persistenceUnit" />
        <property name="dataSource" ref="dataSource" />
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.hbm2ddl.auto">${hibernate.ddl.auto}</prop>
                <prop key="hibernate.dialect">${hibernate.dialect}</prop>
                <prop key="hibernate.show_sql">${hibernate.show.sql}</prop>
                <prop key="hibernate.format_sql">true</prop>
                <prop key="hibernate.cache.use_second_level_cache">${hibernate.enable.cache}</prop>
                <prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</prop>
            </props>
        </property>
    </bean>

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

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

Spring数据源定义示例 

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="
            http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd">

    <bean id="dataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName">
            <value>${database.driver}</value>
        </property>
        <property name="url">
            <value>${database.url}</value>
        </property>
        <property name="username">
            <value>${database.username}</value>
        </property>
        <property name="password">
            <value>${database.password}</value>
        </property>
    </bean>

</beans>

Spring配置文件定义示例： 

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd">

    <beans profile="default">
        <bean id="applicationPropertiesPlaceholder"
            class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
            <property name="locations">
                <list>
                    <value>classpath:profiles/hsqldb.profile.properties</value>
                </list>
            </property>
        </bean>
    </beans>

    <beans profile="hsqldb">
        <bean id="applicationPropertiesPlaceholder"
            class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
            <property name="locations">
                <list>
                    <value>classpath:profiles/hsqldb.profile.properties</value>
                </list>
            </property>
        </bean>
    </beans>

    <beans profile="mysql">
        <bean id="applicationPropertiesPlaceholder"
            class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
            <property name="locations">
                <list>
                    <value>classpath:profiles/mysql.profile.properties</value>
                </list>
            </property>
        </bean>
    </beans>

    <beans profile="mssql">
        <bean id="applicationPropertiesPlaceholder"
            class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
            <property name="locations">
                <list>
                    <value>classpath:profiles/mssql.profile.properties</value>
                </list>
            </property>
        </bean>
    </beans>

</beans>

Minimal Persisteance.XML 

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.0"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
    <persistence-unit name="persistenceUnit"
        transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>
        <properties>
            <property name="hibernate.ejb.naming_strategy" value="org.hibernate.cfg.ImprovedNamingStrategy" />
            <property name="hibernate.connection.charSet" value="UTF-8" />
        </properties>
    </persistence-unit>
</persistence>

示例配置文件属性文件： 

#MySQL
#database.url=jdbc:mysql://localhost:3306/test
database.url=jdbc:log4jdbc:mysql://localhost:3306/test
#database.driver=com.mysql.jdbc.Driver
database.driver=net.sf.log4jdbc.DriverSpy
database.username=root
database.password=password
hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect

hibernate.show.sql=false
hibernate.ddl.auto=create
hibernate.enable.cache=false

答案 1 :(得分：1)

  1. 由于我与Tomcat没有多少共同之处，我只会提供一个类似问题的链接：
    Using dynamic Datasource with Tomcat

  2. JPA允许在单个persistence.xml文件中定义多个持久性单元 您至少需要将其名称更改为其包装范围内的唯一名称（就Web Archive，EJB JAR等而言）：

    <?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="BPPersistenceUnit-postgres" 
                      transaction-type="RESOURCE_LOCAL">
        <!-- JNDI datasource -->
        ...
        <!-- properties -->
        ...
    </persistence-unit>
    <persistence-unit name="BPPersistenceUnit-mysql" 
                      transaction-type="RESOURCE_LOCAL">
        <!-- JNDI datasource -->
        ...
        <!-- properties -->
        ...
    </persistence-unit>
</persistence>

  3. JPA允许使用重载的createEntityManagerFactory方法在运行时指定持久性提供程序属性：

    // dynamic configuration for PostgreSQL
Map<String, String> props = new HashMap<>();
props.put("javax.persistence.jdbc.driver", "org.postgresql.Driver");
...
EntityManagerFactory pgEmf = 
Persistence.createEntityManagerFactory("BPPersistenceUnit-postgres", props);

// dynamic configuration for MySQL
...

    传递给该方法的属性与persistence.xml中已指定的属性相结合，这样您就可以获得真正可配置的多用途和动态配置。

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