Open Liberty Maven项目配置Apache Derby依赖遇连接问题求助

操作步骤 #

• 从Derby官网下载db-derby-10.15.2.0-bin.tar.gz并解压至项目根目录；
• 在server.xml中配置Derby库与数据源：

  <!-- 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META-INF目录创建persistence.xml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>
  

• 在pom.xml中配置liberty-maven-plugin：

  <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>
  

问题现象 #

项目可编译运行，但操作持久化对象时出现错误，启动服务器时收到如下警告：

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].

调整配置后，新的错误信息为：

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].

解决方案 #

原因分析 #

错误提示找不到org.apache.derby.jdbc.EmbeddedConnectionPoolDataSource40实现类，核心问题是Derby驱动包不完整或库引用路径不一致：

1. 同时混用了手动下载的Derby压缩包和Maven依赖的驱动，导致server.xml中配置的library指向目录与实际驱动存放位置不匹配；
2. Derby嵌入式驱动需要derby.jar、derbytools.jar等完整包，仅复制derby.jar和derbyshared.jar缺少必要类。

修复步骤 #

方案一：统一使用Maven管理Derby依赖（推荐）

1. 删除手动下载的db-derby-10.15.2.0-bin目录，避免路径混淆；
2. 修改server.xml，将library配置指向Maven依赖复制的位置：

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

   注：${shared.resource.dir}是Open Liberty内置变量，对应target/liberty/wlp/usr/shared/resources目录；
3. 确保pom.xml中liberty-maven-plugin的copyDependencies包含完整Derby驱动依赖，补充derbytools：

   <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>
                   <version>10.15.2.0</version>
               </dependency>
               <dependency>
                   <groupId>org.apache.derby</groupId>
                   <artifactId>derbytools</artifactId>
                   <version>10.15.2.0</version>
               </dependency>
           </copyDependencies>
       </configuration>
   </plugin>
   

4. 执行mvn clean install liberty:run重新构建启动应用。

方案二：使用手动下载的Derby包

1. 确保db-derby-10.15.2.0-bin/lib目录下包含derby.jar、derbytools.jar、derbyshared.jar等所有JAR包；
2. 修改server.xml的library配置，明确指定包含的JAR文件（避免遗漏）：

   <library id="derbyJDBCLib">
       <fileset dir="db-derby-10.15.2.0-bin/lib" includes="derby*.jar" />
   </library>
   

3. 删除pom.xml中liberty-maven-plugin的copyDependencies配置，避免重复复制导致冲突；
4. 执行mvn clean install liberty:run重新启动。

额外验证 #

启动后可通过Open Liberty控制台的数据源配置页面（路径：https://localhost:9443/adminCenter）验证数据源是否连接成功，检查驱动类是否正确加载。

内容的提问来源于stack exchange，提问作者stitch123