在osgi-container中找不到hibernate-validator的El实现

Question

我尝试在osgi容器中运行Hibernate验证器。

<dependency>
    <groupId>javax.el</groupId>
    <artifactId>javax.el-api</artifactId>
    <version>2.2.4</version>
</dependency>
<dependency>
    <groupId>org.glassfish.web</groupId>
    <artifactId>javax.el</artifactId>
    <version>2.2.4</version>
</dependency>

<dependency>
    <groupId>org.apache.servicemix.bundles</groupId>
    <artifactId>org.apache.servicemix.bundles.hibernate-validator</artifactId>
    <version>5.0.2.Final_1</version>
</dependency>

<dependency>
    <groupId>joda-time</groupId>
    <artifactId>joda-time</artifactId>
    <version>2.7</version>
</dependency>

<dependency>
    <groupId>org.jsoup</groupId>
    <artifactId>jsoup</artifactId>
    <version>1.8.1</version>
</dependency>


public class HibernateValidationProviderResolver implements ValidationProviderResolver {
    @Override
    public List<ValidationProvider<?>> getValidationProviders() {
        List<ValidationProvider<?>> list = new ArrayList<>(1);
        list.add(new HibernateValidator());
        return list;
    }
}


Configuration<?> configuration = Validation.byDefaultProvider().providerResolver(
    new HibernateValidationProviderResolver()
).configure();

ValidatorFactory validatorFactory = configuration.buildValidatorFactory();
Validator validator = validatorFactory.getValidator();
Set<ConstraintViolation<Group>> constraintViolations = validator.validate(group);


public class Group {
    @NotNull
    @Size(min=2)
    private String title;
}

试着运行，equinox控制台没问题：

10      RESOLVED    org.glassfish.web.javax.el_2.2.4
39      RESOLVED    org.apache.servicemix.bundles.hibernate-validator_5.0.2.Final_1
47      RESOLVED    javax.validation.api_1.1.0.Final
49      RESOLVED    javax.el-api_2.2.4

如果传递具有title=null的Group class instance，那么验证就可以了，ConstraintVioldings包含一个违规“not null”。如果传递具有title=“a”的Group class实例（一个字符，最小长度=2)，则会引发异常

Caused by: javax.el.ELException: Provider com.sun.el.ExpressionFactoryImpl not found
Caused by: java.lang.ClassNotFoundException: com.sun.el.ExpressionFactoryImpl

更新1

Maven: javax.el:javax.el-api:2.2.4

Export-Package: javax.el;version="2.2.4"
Import-Package: javax.el;version="2.2.4"

Maven: org.glassfish.web:javax.el:2.2.4 MANIFEST.MF

Export-Package: com.sun.el;uses:="javax.el";version="2.2.4"
Private-Package: com.sun.el.lang;version="2.2.4",com.sun.el.parser;version="2.2.4",com.sun.el.util;version="2.2.4"
Import-Package: com.sun.el;version="2.2.4",javax.el;version="2.2"

Maven: org.apache.servicemix.bundles:org.apache.servicemix.bundles.hibernate-validator:5.0.2.Final_1

Implementation-Version: 5.0.2.Final
Import-Package: javax.el,javax.persistence;resolution:=optional, ...

Export-Package: org.hibernate.validator.internal.engine.messageinterpola
tion.el;uses:="javax.el,javax.validation,org.hibernate.validator.intern
al.engine.messageinterpolation";version="5.0.2.Final",org.hibernate.val
idator.internal.engine.messageinterpolation;uses:="javax.validation.met
adata,org.hibernate.validator.internal.engine.messageinterpolation.el,j
avax.el,javax.validation,org.hibernate.validator.internal.util.logging"
;version="5.0.2.Final", ...

在hibernate bundle中导入的任何版本，在el-api和el-impl的导出中的2.2.4和el-impl将el-api作为2.2而不是2.2.4导入。所有包都已解析。

更新2

决定1

我对@Hwellmann想法的实现。@Hwellmann对吗？

public void createGroup(Group group) {
    ClassLoader prevClassLoader = Thread.currentThread().getContextClassLoader();

    try {
        ClassLoader[] classLoaders = new ClassLoader[] {
            prevClassLoader,
            ExpressionFactoryImpl.class.getClassLoader()
        };

        // build composite classloader

        Thread.currentThread().setContextClassLoader(compositeClassLoader);

        Set<ConstraintViolation<Group>> constraintViolations = validator.validate(group);

    } finally {
        Thread.currentThread().setContextClassLoader(prevClassLoader);
    }
}

当我将自己的消息属性添加到每个验证注释（例如group：

public class Group {
    @NotNull
    @Size(min=2, message="field.too_short")
    private String title;
}

在本例中，似乎未启动hibernate插值器，因此未从TCCL检索expressionFactoryImpl（以前我们读取min=2值，现在不读取）。如果对我们来说可以的话，这个决定是最简单的。我将进一步调查这一领域，并在那里分享我的观察。

Answer 1

完整的堆栈跟踪可能比仅提供异常消息提供更多的洞察力。

我猜测您正在通过meta-inf/service/javax.el.expressionFactory看到一个失败的服务查找的结果。进行查找的包显然看不到com.sun.el。

将此包导入应用程序包并将线程上下文类加载器设置为包类加载器可能会有所帮助。