对使用 Open Liberty 设置 Apache Derby 感到困惑

Question

我正在尝试将 Derby 数据库连接到我的 Open Liberty 应用程序，但我无法让它工作。我认为我没有正确理解这个过程。这就是我所做的。

我从德比网站下载了

db-derby-10.15.2.0-bin.tar.gz

，并将其解压到我的项目的根文件夹中。

我将以下内容放入我的

server.xml

文件中：

<!-- Derby Library Configuration -->
    <library id="derbyJDBCLib">
        <fileset dir="db-derby-10.15.2.0-bin/lib" />
    </library>

    <!-- Datasource Configuration -->
    <dataSource id="derbyjpadatasource" jndiName="jdbc/my-project">
        <jdbcDriver libraryRef="derbyJDBCLib" />
        <properties.derby.embedded databaseName="myDB" createDatabase="create" />
    </dataSource>

在我的

persistence.xml

文件夹中创建了一个

META-INF

文件：

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.2"
             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_2.xsd">
    <persistence-unit name="jpa-unit" transaction-type="JTA">
        <jta-data-source>jdbc/my-project</jta-data-source>
        <properties>
            <property name="jakarta.persistence.schema-generation.database.action"
                      value="create"/>
            <property name="jakarta.persistence.schema-generation.scripts.action"
                      value="create"/>
            <property name="jakarta.persistence.schema-generation.scripts.create-target"
                      value="createDDL.ddl"/>
        </properties>
    </persistence-unit>
</persistence>

并编辑了我的

pom.xml

文件，使其包含以下内容：

<plugin>
                <groupId>io.openliberty.tools</groupId>
                <artifactId>liberty-maven-plugin</artifactId>
                <version>3.7.1</version>
                <configuration>
                    <copyDependencies>
                        <location>${project.build.directory}/liberty/wlp/usr/shared/resources</location>
                        <dependency>
                            <groupId>org.apache.derby</groupId>
                            <artifactId>derby</artifactId>
                        </dependency>
                    </copyDependencies>
                </configuration>
</plugin>

项目编译运行，但是对持久化对象的任何操作都会出错。这是我在运行服务器时看到的警告之一：

DSRA4000E: No implementations of org.apache.derby.jdbc.EmbeddedConnectionPoolDataSource40
for dataSource [derbyjpadatasource] with library derbyJDBCLib were found.
The name or location of the JDBC driver JAR files may be incorrect
or inaccessible. Searched in: []. Searched in packages: [org.apache.derby.jdbc].

编辑： Scott Kurz 建议后的新错误消息：

DSRA4000E: No implementations of 
org.apache.derby.jdbc.EmbeddedConnectionPoolDataSource40 were 
found for dataSource[derbyjpadatasource] with the library 
derbyJDBCLib. The name or location of the JDBC driver JAR files 
may be incorrect or inaccessible. Searched in 
[/home/(my_usr)/Desktop/Projects/proj1/target/liberty/
wlp/usr/shared/resources/derby-10.15.2.0.jar, 
/home/(my_usr)/Desktop/Projects/proj1/target/liberty/
wlp/usr/shared/resources/derbyshared-10.15.2.0.jar]. Searched in 
packages: [org.apache.derby.jdbc].

Answer 1

copyDependencies in liberty-maven-plugin

liberty-maven-plugin 中 copyDependencies 函数背后的想法是，您可以让插件将依赖项复制到位，而无需单独下载、存储，然后担心将此依赖项 JAR 复制到正确的位置。

所以如果你有

pom.xml

       <!-- In the dependencies section -->
        <dependency>
            <groupId>org.apache.derby</groupId>
            <artifactId>derby</artifactId>
            <version>10.15.2.0</version>
            <scope>provided</scope>
        </dependency>

         ...

       <!-- plugin configuration in build/plugins -->
        <groupId>io.openliberty.tools</groupId>
        <artifactId>liberty-maven-plugin</artifactId>
        <version>3.7.1</version>
        <configuration>
           <copyDependencies>
            <location>${project.build.directory}/liberty/wlp/usr/shared/resources</location>
            <dependency>
             <groupId>org.apache.derby</groupId>
             <artifactId>derby</artifactId>
            </dependency>
          </copyDependencies>
        </configuration>

您可以将其与 server.xml 配置结合使用：

服务器.xml

  <library id="derbyJDBCLib">
    <fileset dir="${shared.resource.dir}/" includes="derby*.jar" />
  </library>

您可以在我们的 JPA 指南示例中看到这一点：https://openliberty.io/guides/jpa-intro.html