Java 无法连接到互联网 - java.net.ConnectException 连接超时
Java can't connect to internet - java.net.ConnectException connection timed out
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：
<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>
这是例外情况：
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.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，它吐出了这个：
Cannot find the declaration of element 'persistence'
OpenJPA 的增强器正在打开 persistence.xml 和 Java 1.8 的 Xerces XML 处理试图从网上抓取 http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd。
进行了一些调试以找到该发现 - grrrr。
我发现我工作的公司的 DNS 崩溃了。我可以在浏览器 - firefox 或 IE - 中获取 XSD 文件，但如果我使用 curl，我会发现它无法连接并且 IP 地址错误。
我怎样才能：
(a) 发现 XSD 文件的 IP 地址或
(b) 指示 Java 或 Maven 从本地文件
中获取 XSD
谢谢
最后，在 schemaLocation 中指定一个本地文件非常简单，但 IntelliJ 并没有始终如一地将 persistence.xml 文件复制到 target/classes/META_INF 构建目录，这让事情变得更加令人沮丧.
这是我的本地化 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>
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：
<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>
这是例外情况：
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.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，它吐出了这个：
Cannot find the declaration of element 'persistence'
OpenJPA 的增强器正在打开 persistence.xml 和 Java 1.8 的 Xerces XML 处理试图从网上抓取 http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd。
进行了一些调试以找到该发现 - grrrr。
我发现我工作的公司的 DNS 崩溃了。我可以在浏览器 - firefox 或 IE - 中获取 XSD 文件，但如果我使用 curl，我会发现它无法连接并且 IP 地址错误。
我怎样才能：
(a) 发现 XSD 文件的 IP 地址或 (b) 指示 Java 或 Maven 从本地文件
中获取 XSD谢谢
最后，在 schemaLocation 中指定一个本地文件非常简单，但 IntelliJ 并没有始终如一地将 persistence.xml 文件复制到 target/classes/META_INF 构建目录，这让事情变得更加令人沮丧.
这是我的本地化 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>