Eclipse 无法识别persistence.xml 的内容

Question

Im getting the following error in eclipse:

The persistence.xml file does not have recognized content.

My persistence.xml file works great in my application but eclipse keeps giving me this error. I got this after moving the file and updating my project configuration with m2eclipse. I did not change the file itself. Anyone knows how to solve this?

persistence.xml:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" 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">
    <persistence-unit name="localDB" transaction-type="RESOURCE_LOCAL">

        <provider>org.apache.openjpa.persistence.PersistenceProviderImpl</provider>
        <class>package.Users</class>
        <properties>
            <!-- enable warnings for debugging -->
            <property name="openjpa.Log" value="DefaultLevel=TRACE, Runtime=INFO, Tool=INFO, SQL=TRACE"/>
            <!-- connection properties -->
            <property name="openjpa.ConnectionURL" value="jdbc:mysql://localhost/test"/>
            <property name="openjpa.ConnectionDriverName" value="com.mysql.jdbc.Driver"/>
            <property name="openjpa.ConnectionUserName" value="root"/>
            <property name="openjpa.ConnectionPassword" value=""/>

        </properties>
    </persistence-unit>
</persistence>

Update

Looks like a bug in m2eclipse in combination with jpa.

https://bugs.eclipse.org/bugs/show_bug.cgi?id=251323

Temporarily solved by setting the option to show it as a warning instead of an error

Answer 1

I fixed the problem the following way (I'm using RAD v8.5.1):

1. Windows --> Preferences --> Validation
2. Scroll down to "JPA Validator" and click on the Ellipses under Settings.
3. Click on the "Add Include Group..." button.
4. Click on the new Include Group that appeared to highlight it.
5. Click on the "Add Rule..." button.
6. A dialog menu pops up. Click the "Folder or file name" radio button and click on "Next".
7. Click on "Browse Folder..." and navigate to your src directory (in my case, it was "src/main/resources") within your project (my project was a .war in a multi module app) in your workspace.
8. Click on "Finish".
9. Click on "OK". This will prompt a full build.
10. The error will go away.

Answer 2

Had same problem with error

The persistence.xml file does not have recognized content

Fixed by editing file in eclipse, any edit will do. And after saving error got away.

Answer 3

<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">

Worked for me!

Answer 4

I figured out what the problem is here.... the JPA Facet is assuming that the META-INF folder is directly under a source folder. If you are using a Maven project, you likely have something like src/main/resources or src/test/resources. If your persistence.xml is under these folders it will complain. If you create a new source folder (call it "jpa") and create a META-INF/persistence.xml in there, then it will find it successfully. (I also had to do a clean/close/open project)

This is certainly a pain.... and I can see many situations this won't work well.

Answer 5

I had this same problem in Eclipse 3.6 (Helios). The cause was the JPA Facet was set to JPA Version 1.0, however my persistence.xml file was specifying JPA Version 2. So I changed the JPA Facet to version 2.0 and the problem went away. (Project --> Properties --> Project Facets --> "Configuration" drop down --> set this to "Minimal JPA 2.0 configuration"

Answer 6

Turning this error into a warning may make the problem go away, but it will not fix the underlying problem with the Eclipse Dali plugin. It will also mean the extremely useful JPA Structure and JPA Details views will not work.

The link offered by OP and the approach of most of the answers here are actually meant to get around a different problem wherein Maven wants to filter the persistence.xml file and thus tells Eclipse to ignore it. A viable work-around for that problem is explained here and involves removing the exclused: '**' from the src/main/resources entry in the classpath in the project properties.

Back to the OP's original question, I had this EXACT same error message (which in and off itself tells you that the persistence.xml file has been located). For me the solution was to change the persistence XML element from this:

<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_1_0.xsd"
    version="1.0">

to this:

<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">

Once changed, the error went away and Dali instantly came alive and now everything Just Works. Hope this helps somebody someday.

Answer 7

The bug has reappeared for certain Indigo (3.7) versions. See here: https://bugs.eclipse.org/bugs/show_bug.cgi?id=357810

Right-click project -> Maven -> Update Project Configuration...

This might destroy certain buildpath entries and/or the deployment assembly, very annoying, so only do this when changing Maven deps.

To workaround the persistence.xml message until the patch is released, you need to clean the project on many operations as even setting the error level to "ignore" doesn't work . This is a complete bummer.

Answer 8

Any updates on this? This is still an issue it seems right? If I create a JPA project, convert to Maven project, the error appears and I can't get rid of it with any of the recommended methods.

Edit

Ok so after maneuvering some folders around so its in an actual Maven directory format , it still didn't work - but creating a linked folder under src/main/java named META-INF, linked to src/main/resources/META-INF it was resolved.

Creating a Maven project and adding the JPA facet works also, but only because the JPA facet adds the META-INF and persistence.xml file to src/main/java which I don't think is exactly right.

Answer 9

No Need to change andthing in your xml file and no need to add xml in src folder. Put your persistance.xml file in META-INF folder and then put META-INF src/main/resource folder. Try following approach: Right click on project> Java Build path > Source Tab > ProjectName/src/main/resource > set Included(All) and Excluded(None). then clean and build your project. It will work for you. Tried this approach on RAD 7 & 8..5 & Eclipse.

Answer 10

This problems occurs if you

• Convert a JPA project to a Maven project or
• Add the JPA facet to a Maven project.

The solution is

• Select Windows > Preferences > Validation
• Disable the JPA Validator for both Manual validation and Build validation

After changing these settings,then clean your project.

Answer 11

I am using eclipse mars and had this same exact error. What I had to do was 1 set the version of jpa for the project facet. right click project -> Properties -> Project Facets Set version of jpa to 2.1 in my case.

Note: Just configuring the jpa project facet will not remove the error. You also need to configure the platform.

Next I had to configure the JPA platform. right click project -> Properties -> JPA . Change platoform to be Hibernate 2.1 in my case.

This problem also manifests itself when you open the persistence.xml with the Persistence XML Editor and you only have a single Source tab at the bottom and not the other tabs for General, Connection, Options, Properties etc.

Answer 12

我通过转到 Project - Properties - Java Persistence: 然后将“Canonical metamodel (JPA 2.0)”部分中的“Source Folder”设置为：“src/generated/resources”来解决这个问题

Answer 13

I had src/main/java/META-INF/persistence.xml working fine in Eclipse with embedded Tomcat. Because it was not being copied into the Maven-built WAR, I moved it to src/main/resources/META-INF .

Now src/main/resources/META-INF/persistence.xml won't validate.

If rename to xyz_persistence.xml, it validates fine.
If rename to persistence.xml, it fails to validate.

When these annoying situations arise, I often find numerous different "solutions" like mine, most of which are not universally applicable.

So, here's my "solution", which I think it a hack to get around a bug:

To remove the error "persistence.xml file does not have recognized content" error, disable the JPA Validator:

• List item Select menu item Project > Properties > Preferences > Validation
• List item Disable the JPA Validator for both Manual validation and Build validation.

You might need to clean and rebuild. Your mileage may vary.

Answer 14

I got the issue fixed by creating a "symbolic link" in Eclipse. So, my persistence.xml file remains in src/main/resources/META-INF as Maven expects and m2eclipse requires. However, in order to fix the Dali issues, create a new file in src/main/java/META-INF that links to the one in src/main/resources/META-INF. You do this by hitting the "Advanced" options when creating the new file and locating the file using the "Browse..." button. Note that this will not create a physical file in the META-INF folder, however, you need the folder itself in order to create the link.

Hope that works for you.

Answer 15

I had the same error, but solved it in a different way.

The thing is that META-INF must be considered a source folder, and as it was under /ejbModule (mine is a EJB project) I assumed it was on the build path. And it wasn't. Actually it was on "exclude" list on build path. So, all I did was right-click the META-INF folder on Project Explorer view and selected INCLUDE on Build Path menu. Then I asked Eclipse to clean the project and everything was right again.

Best Regards.

Answer 16

I've had the same problem. My solution: right click on the persistence.xml file -> JPA-Tools -> Synchronize Class List. After that it was resolved.

Answer 17

In my case it was the Maven plugin which has a bug that sets "Exclude" to . in the Build path for your resources folder. Removing . solved the issue for me

Answer 18

I got it fixed by dragging META-INF folder to src/main/resources and drag it back to src/test/resources. Thats all it took for me to fix the issue. I tried above given all steps but none of those seem to be working for me and finally this one done the trick.

Answer 19

just solved the issue by doing this:

1. in schemaLocation, i deleted "h ttp://java.sun.com/xml/ns/persistence/" making it:

xsi:schemaLocation="http://java.sun.com/xml/ns/persistence persistence_2_0.xsd"

1. i added <?xml version="1.0" encoding="UTF-8"?> at the top.

2. i clean build the project. error's gone.

3. i added the "h ttp://java.sun.com/xml/ns/persistence/" again:

xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd "

1. i clean build the project. error's not there.

2. i deleted <?xml version="1.0" encoding="UTF-8"?> at the top.

3. i clean build the project. error's still not there.

hope this helps someone in the future.

Answer 20

Ok ... another rather robust solution that worked for me since the top-most ones did not:

• since I used Mercurial and could go back easily without any notable differences in the current and last versions it worked this way:

• ( committed some important changes rather unrelated to this problem )

• switching to previous repo version
• ( auto-/refresh/-rebuild ran fine )

What I recognized was, that the problem may have been due to the fact that the Java Builder did not generate my war/WEB-INF/classes/ files . The following did not work to follow this trail in letting it build my project:

• disabling/reconfiguring Validators, Builders, Facets (till only the Java Builder/Facet was there)
• renaming the persistence.xml or editing it in various ways

which did not help it as if some internal state could not be changed.

Answer 21

Whereabouts in your project structure is the file located?

For ref, I have mine in maven-module-name/src/main/resources/META-INF/

Answer 22

Hard to say since hard to reproduce (your persistence.xml is perfectly valid) but maybe try to:

• Clean the project (both an "Project > Clean" and a Maven clean )
• Force Eclipse to validate the XML file again (right-click, and select Validate XML file).

Answer 23

我有几次遇到同样的问题，对我有用的是复制文件的内容，删除它并创建一个新的 persistence.xml 文件并将内容粘贴回。

Answer 24

I came accross the same problem. Goto project properties -> Java build path -> source , remove * / .java excluded attribute of src/main/resources source. Then add META-INF/persistence.xml. Then restart eclipse. You should persistence.xml under JPA Content in Project explorer. After that revert your changes.

Well, what I suggest seem stupid, but magically it works. By the way my eclipse version is 3.6.

Answer 25

对我来说，一旦我清除了 eclipse 中 Markers 选项卡中的所有消息，它就起作用了

Answer 26

Add your JPA Version to the Project Facets to remove this error.

In my case i have used JPA 2.2 but in Project Facets JPA 1.0 was specified. After fixing this, the error disappeared.

Answer 27

The problem has been fixed in Indigo (released in June 2011), see https://bugs.eclipse.org/bugs/show_bug.cgi?id=251323#c24 and https://issues.sonatype.org/browse/MECLIPSEWTP-11 .

The "persistence.xml file does not have recognized content." error might still appear, randomly, on project import or Workspace startup, but it can be fixed with a project clean or maven project update. This will be fixed in Dali in SR2.

Answer 28

我有同样的问题，为了让它消失，我必须确保这一行是文件顶部的第一行（没有前导空行或空格）：

<?xml version="1.0" encoding="UTF-8"?>