1

嗨，我有一个用 @Entity 注释的实体类，因此它可以在谷歌应用引擎上使用 JPA 持久化。

我的课看起来像这样：

@Entity
public class DataUrls {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Key key;

private String postalCode;

private List<String> urls;

public Key getKey() {
    return key;
}

public void setKey(Key key) {
    this.key = key;
}

public String getPostalCode() {
    return postalCode;
}

public void setPostalCode(String postalCode) {
    this.postalCode = postalCode;
}

public List<String> getUrls() {
    return urls;
}

public void setUrls(List<String> urls) {
    this.urls = urls;
}
}

我正在使用 maven 构建我的项目并在编译阶段增强类，在我的日志记录中我看到以下内容：

[INFO] --- maven-datanucleus-plugin:3.1.1:enhance (default) @ grabby-backend ---
[INFO] DataNucleus Enhancer (version 3.1.1) : Enhancement of classes
DataNucleus Enhancer completed with success for 1 classes. Timings : input=181 ms,     enhance=60 ms, total=241 ms. Consult the log for full details

[ERROR] --------------------
[ERROR]  Standard error from the DataNucleus tool +     org.datanucleus.enhancer.DataNucleusEnhancer :
[ERROR] --------------------
[ERROR] Nov 14, 2013 5:00:01 PM org.datanucleus.enhancer.DataNucleusEnhancer <init>
INFO: DataNucleus Enhancer for API "JPA"
Nov 14, 2013 5:00:02 PM org.datanucleus.enhancer.DataNucleusEnhancer main
INFO: DataNucleus Enhancer (version 3.1.1) : Enhancement of classes
Nov 14, 2013 5:00:02 PM org.datanucleus.metadata.MetaDataManager loadFiles
WARNING: Metadata file -enhancerName not found in CLASSPATH
Nov 14, 2013 5:00:02 PM org.datanucleus.metadata.MetaDataManager loadFiles
WARNING: Metadata file ASM not found in CLASSPATH
Nov 14, 2013 5:00:02 PM org.datanucleus.enhancer.AbstractClassEnhancer save
INFO: Writing class file "/Development/datagrabber-backend/grabby-    backend/target/classes/com/appspot/datagrabby/model/entities/DataUrls.class" with enhanced     definition
Nov 14, 2013 5:00:02 PM org.datanucleus.enhancer.DataNucleusEnhancer addMessage
INFO: DataNucleus Enhancer completed with success for 1 classes. Timings : input=181 ms,     enhance=60 ms, total=241 ms. Consult the log for full details

maven 中的配置如下所示：

<plugin>
            <groupId>org.datanucleus</groupId>
            <artifactId>maven-datanucleus-plugin</artifactId>
            <version>${datanucleus.jpa.version}</version>

            <configuration>
                <api>JPA</api>
                <metadataIncludes>com/appspot/blabla/model/entities/*.class</metadataIncludes>
                <verbose>true</verbose>
                <enhancerName>ASM</enhancerName>
            </configuration>

            <dependencies>
                <dependency>
                    <groupId>org.datanucleus</groupId>
                    <artifactId>datanucleus-core</artifactId>
                    <version>${datanucleus.jpa.version}</version>
                </dependency>
            </dependencies>

            <executions>
                <execution>
                    <phase>compile</phase>
                    <goals>
                        <goal>enhance</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>

持久性代码：

    public void persistDataURLs(DataUrls dataUrls){
        EntityManager em = EMF.getFactory().createEntityManager();
        em.persist(dataUrls);
        em.close();
    }

但是，当我尝试写入数据库时​​，我收到以下消息：

Type ("XXX") is not that of an entity but needs to be for this operation

我理解应用程序为什么这么说，但是由于增强器插件的日志记录通知该类已增强，我想知道为什么会发生这种情况。

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1 回答 1

1

我今天遇到了同样的问题。我想一旦我找到了我会分享的解决方案。

除了不同的用例（显然）之外，我的代码与您的代码几乎相同。问题是我忘记用我试图持久化的新实体的位置更新我的 persistence.xml 文件。因此，DN 没有将类识别为实体的原因。

于 2015-09-01T20:07:08.880 回答