Java无法连接到Internet-java.net.ConnectException连接超时

Question

这是在我的maven项目中使用OpenJPA 2.4.2来自动化JPA实体的构建时增强功能：

<plugin>
    <groupId>org.apache.openjpa</groupId>
    <artifactId>openjpa-maven-plugin</artifactId>
    <configuration>
        <includes>**/entity/*.class</includes>
        <addDefaultConstructor>true</addDefaultConstructor>
        <enforcePropertyRestrictions>true</enforcePropertyRestrictions>
        <persistenceXmlFile>src/main/resources/META-INF/persistence.xml</persistenceXmlFile>
    </configuration>
    <executions>
        <execution>
            <id>enhancer</id>
            <phase>process-classes</phase>
            <goals>
                <goal>enhance</goal>
            </goals>
        </execution>
    </executions>
</plugin>

这是例外：

java.net.ConnectException: Connection timed out: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at java.net.Socket.connect(Socket.java:538)
at sun.net.NetworkClient.doConnect(NetworkClient.java:180)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:463)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:558)
at sun.net.www.http.HttpClient.<init>(HttpClient.java:242)
at sun.net.www.http.HttpClient.New(HttpClient.java:339)
at sun.net.www.http.HttpClient.New(HttpClient.java:357)
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1202)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1138)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1032)
at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:966)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1546)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1474)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.setupCurrentEntity(XMLEntityManager.java:647)
at com.sun.org.apache.xerces.internal.impl.XMLVersionDetector.determineDocVersion(XMLVersionDetector.java:148)
at com.sun.org.apache.xerces.internal.impl.xs.opti.SchemaParsingConfig.parse(SchemaParsingConfig.java:582)
at com.sun.org.apache.xerces.internal.impl.xs.opti.SchemaParsingConfig.parse(SchemaParsingConfig.java:685)
at com.sun.org.apache.xerces.internal.impl.xs.opti.SchemaDOMParser.parse(SchemaDOMParser.java:530)
at com.sun.org.apache.xerces.internal.impl.xs.traversers.XSDHandler.getSchemaDocument(XSDHandler.java:2179)
at com.sun.org.apache.xerces.internal.impl.xs.traversers.XSDHandler.parseSchema(XSDHandler.java:576)
at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaLoader.loadSchema(XMLSchemaLoader.java:613)
at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.findSchemaGrammar(XMLSchemaValidator.java:2446)
at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.handleStartElement(XMLSchemaValidator.java:1767)
at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.startElement(XMLSchemaValidator.java:740)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:374)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl$NSContentDriver.scanRootElementHook(XMLNSDocumentScannerImpl.java:613)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:3132)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:852)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:602)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:112)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:505)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:841)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:770)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1213)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:643)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse(SAXParserImpl.java:327)
at org.apache.openjpa.lib.meta.XMLMetaDataParser.parseNewResource(XMLMetaDataParser.java:423)
at org.apache.openjpa.lib.meta.XMLMetaDataParser.parse(XMLMetaDataParser.java:346)
at org.apache.openjpa.lib.meta.XMLMetaDataParser.parse(XMLMetaDataParser.java:323)
at org.apache.openjpa.lib.meta.XMLMetaDataParser.parse(XMLMetaDataParser.java:304)
at org.apache.openjpa.persistence.PersistenceProductDerivation$ConfigurationParser.parse(PersistenceProductDerivation.java:833)
at org.apache.openjpa.persistence.PersistenceProductDerivation.load(PersistenceProductDerivation.java:375)
at org.apache.openjpa.lib.conf.ProductDerivations.load(ProductDerivations.java:310)
at org.apache.openjpa.lib.conf.ConfigurationImpl.setPropertiesFile(ConfigurationImpl.java:888)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.openjpa.lib.util.Options.invoke(Options.java:401)
at org.apache.openjpa.lib.util.Options.setInto(Options.java:235)
at org.apache.openjpa.lib.util.Options.setInto(Options.java:191)
at org.apache.openjpa.lib.conf.Configurations.populateConfiguration(Configurations.java:369)
at org.apache.openjpa.enhance.PCEnhancer.run(PCEnhancer.java:4833)
at org.apache.openjpa.enhance.PCEnhancer$1.run(PCEnhancer.java:4804)
at org.apache.openjpa.lib.conf.Configurations.launchRunnable(Configurations.java:764)
at org.apache.openjpa.lib.conf.Configurations.runAgainstAllAnchors(Configurations.java:749)
at org.apache.openjpa.enhance.PCEnhancer.run(PCEnhancer.java:4799)
at org.apache.openjpa.tools.maven.AbstractOpenJpaEnhancerMojo.enhance(AbstractOpenJpaEnhancerMojo.java:131)
at org.apache.openjpa.tools.maven.AbstractOpenJpaEnhancerMojo.execute(AbstractOpenJpaEnhancerMojo.java:93)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:207)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:863)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:199)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
at org.codehaus.classworlds.Launcher.main(Launcher.java:47)

上面的异常被Java吞没了，它抛出了这个异常：

Cannot find the declaration of element 'persistence'

OpenJPA的增强程序正在打开persistence.xml而Java 1.8的Xerces XML处理正在尝试从网上获取http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd 。

进行了一些调试才能找到该文件-grrrr。

我发现我工作所在的公司的DNS很麻烦。 我可以在浏览器中获取XSD文件-firefox或IE-但是，如果我使用curl ，我会发现它无法连接，并且IP错误。

我怎么可以：

（a）发现XSD文件的IP地址，或（b）指示Java或Maven从本地文件获取XSD

谢谢

Answer 1

最后，在schemaLocation中指定本地文件非常简单，但是IntelliJ却使它更加沮丧，因为IntelliJ并没有将persistence.xml文件始终复制到target/classes/META_INF目录target/classes/META_INF构建目录中。

这是我本地化的persistence.xml ：

<?xml version="1.0" encoding="UTF-8" ?>
<persistence version="2.1"
        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
            persistence_2_1.xsd">
    <persistence-unit name="default">
        <provider>org.apache.openjpa.persistence.PersistenceProviderImpl</provider>
        <class>com.xyz.entity.MyEntity</class>
    </persistence-unit>
</persistence>