OSGI : maven wrapped bundle throws java. lang.ClassNotFoundException 如果它试图访问另一个包装包

Question

由于以下依赖项不是 OSGI 就绪的，所以我将它们包装如下:

  <bundle>wrap:mvn:com.google.maps/google-maps-services/0.9.2</bundle>
  <bundle>wrap:mvn:com.squareup.okhttp3/okhttp/3.13.1</bundle>

似乎我的第一个包无法访问第二个包，尽管我按如下方式将其包含在我的导入中:

<Import-Package>okhttp3,*</import-Package>

我得到:

Caused by: java.lang.NoClassDefFoundError: okhttp3/Authenticator
    at com.google.maps.GeoApiContext$Builder.<init>(GeoApiContext.java:318)
    at com.elavon.nabsd.creditsafe.beans.GooglePlacesAPIContext.<clinit>(GooglePlacesAPIContext.java:11)
    at com.elavon.nabsd.creditsafe.beans.AddressParser.getAddress(AddressParser.java:35)
    at com.elavon.nabsd.creditsafe.beans.AddressParser.dummyResponse(AddressParser.java:76)
    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.camel.component.bean.MethodInfo.invoke(MethodInfo.java:408)
    at org.apache.camel.component.bean.MethodInfo$1.doProceed(MethodInfo.java:279)
    at org.apache.camel.component.bean.MethodInfo$1.proceed(MethodInfo.java:252)
    ... 13 more
Caused by: java.lang.ClassNotFoundException: okhttp3.Authenticator not found by wrap_mvn_com.google.maps_google-maps-services_0.9.2 [1180]
    at org.apache.felix.framework.BundleWiringImpl.findClassOrResourceByDelegation(BundleWiringImpl.java:1556)
    at org.apache.felix.framework.BundleWiringImpl.access$400(BundleWiringImpl.java:77)
    at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.loadClass(BundleWiringImpl.java:1993)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 24 more

---

list

Manifest-Version: 1.0
Bnd-LastModified: 1552097042208
Build-Jdk: 1.8.0_181
Built-By: c041356
Bundle-Blueprint: OSGI-INF/blueprint/address-parser-blueprint.xml
Bundle-Description: XXX
Bundle-DocURL: XXX
Bundle-ManifestVersion: 2
Bundle-Name: XXX
Bundle-SymbolicName: address-parser
Bundle-Vendor: XXX
Bundle-Version: 1.0.24
Created-By: Apache Maven Bundle Plugin
DynamicImport-Package: *
Export-package: com.squareup.okhttp3,okhttp3
Import-Package: okhttp3,com.fasterxml.jackson.annotation,com.google.maps
 ,com.google.maps.errors,com.google.maps.model,org.apache.camel.componen
 t.jasypt,org.jasypt.encryption.pbe.config,org.osgi.service.blueprint;ve
 rsion="[1.0.0,2.0.0)",org.slf4j,org.apache.camel.component.http4,org.ap
 ache.camel.component.jackson,com.squareup.okhttp3
Require-Capability: osgi.ee;filter:="(&(osgi.ee=JavaSE)(version=1.8))"
Tool: Bnd-3.0.0.201509101326

---

wrap_mvn_com.squareup.okhttp3_okhttp_3.13.1 (1202)
--------------------------------------------------
Originally-Created-By = Apache Maven 3.6.0
Created-By = 1.8.0_181 (Oracle Corporation)
Manifest-Version = 1.0
Bnd-LastModified = 1552095323499
Generated-By-Ops4j-Pax-From = wrap:mvn:com.squareup.okhttp3/okhttp/3.13.1
Build-Jdk = 1.8.0_162
Built-By = jwilson
Automatic-Module-Name = okhttp3
Tool = Bnd-2.3.0.201405100607

Bundle-ManifestVersion = 2
Bundle-SymbolicName = wrap_mvn_com.squareup.okhttp3_okhttp_3.13.1
Bundle-Version = 0
Bundle-Name = wrap_mvn_com.squareup.okhttp3_okhttp_3.13.1

Require-Capability =
        osgi.ee;filter:=(&(osgi.ee=JavaSE)(version=1.8))

Export-Package =
        okhttp3;uses:="javax.annotation,javax.net,javax.net.ssl,okio",
        okhttp3.internal;uses:="javax.annotation,javax.net.ssl,okhttp3,okhttp3.internal.cache,okhttp3.internal.connection,okhttp3.internal.http,okhttp3.internal.http2,okio",
        okhttp3.internal.annotations;uses:="javax.annotation,javax.annotation.meta",
        okhttp3.internal.cache;uses:="javax.annotation,okhttp3,okhttp3.internal.io,okio",
        okhttp3.internal.cache2,
        okhttp3.internal.connection;uses:="javax.annotation,javax.net.ssl,okhttp3,okhttp3.internal.http,okhttp3.internal.http2,okhttp3.internal.ws",
        okhttp3.internal.duplex,
        okhttp3.internal.http;uses:="javax.annotation,okhttp3,okhttp3.internal.connection,okio",
        okhttp3.internal.http1;uses:="okhttp3,okhttp3.internal.connection,okhttp3.internal.http,okio",
        okhttp3.internal.http2;uses:="okhttp3,okhttp3.internal.connection,okhttp3.internal.http,okio",
        okhttp3.internal.io;uses:=okio,
        okhttp3.internal.platform;uses:="javax.annotation,javax.net.ssl,okhttp3,okhttp3.internal.tls",
        okhttp3.internal.proxy,
        okhttp3.internal.publicsuffix,
        okhttp3.internal.tls;uses:=javax.net.ssl,
        okhttp3.internal.ws;uses:="javax.annotation,okhttp3,okio"
Import-Package =
        android.os;resolution:=optional,
        android.util;resolution:=optional,
        javax.annotation;resolution:=optional,
        javax.annotation.meta;resolution:=optional,
        javax.net;resolution:=optional,
        javax.net.ssl;resolution:=optional,
        javax.security.auth.x500;resolution:=optional,
        okio;resolution:=optional,

---

wrap_mvn_com.google.maps_google-maps-services_0.9.2 (1180)
----------------------------------------------------------
Created-By = 1.8.0_181 (Oracle Corporation)
Manifest-Version = 1.0
Bnd-LastModified = 1552091296783
Generated-By-Ops4j-Pax-From = wrap:mvn:com.google.maps/google-maps-services/0.9.2
Tool = Bnd-2.3.0.201405100607

Bundle-ManifestVersion = 2
Bundle-SymbolicName = wrap_mvn_com.google.maps_google-maps-services_0.9.2
Bundle-Version = 0
Bundle-Name = wrap_mvn_com.google.maps_google-maps-services_0.9.2

Require-Capability =
        osgi.ee;filter:=(&(osgi.ee=JavaSE)(version=1.8))

Export-Package =
        com.google.maps;uses:="com.google.gson,com.google.maps.errors,com.google.maps.internal,com.google.maps.model,okhttp3",
        com.google.maps.errors,
        com.google.maps.internal;uses:="com.google.appengine.api.urlfetch,com.google.gson,com.google.gson.stream,com.google.maps,com.google.maps.errors,com.google.maps.model,okhttp3",
        com.google.maps.internal.ratelimiter,
        com.google.maps.model;uses:=com.google.maps.internal
Import-Package =
        com.google.appengine.api.urlfetch;resolution:=optional,
        com.google.gson;resolution:=optional,
        com.google.gson.stream;resolution:=optional,
        javax.crypto;resolution:=optional,
        javax.crypto.spec;resolution:=optional,
        okhttp3;resolution:=optional,
        okio;resolution:=optional,
        org.slf4j;resolution:=optional

Answer 1

包装的 bundle 将自动发现的包依赖项作为“可选”，因为在使用 bundle 提供的特定功能时，无法可靠地判断是否实际需要某些特定的包。

因此，其他包及其导出包在包解析时的存在决定了哪些包对于已解析的包装包的创建的类加载器实际上是可见的。

在您的情况下，当解析器在解析 bundle “google-maps”时搜索要导入的可用包时， bundle “okhttp3”导出的包不可用。

这反过来意味着您需要确保:

1. 在解析包“google-maps”时，解析器可以看到包“okhttp3”
2. 确保所需的包导入不是“可选的”

虽然第一种选择似乎更容易，但第二种选择更可靠、更灵活。

wrap: protocol支持覆盖生成的 OSGi header ，以便您可以根据需要指定详细信息。在我们的例子中，它将是:

<bundle>wrap:mvn:com.google.maps/google-maps-services/0.9.2$overwrite=merge&amp;Import-Package=okhttp3,okio,*;resolution:=optional</bundle>

(虽然未经测试且仅基于文档)

注意事项

在使用wrap 协议(protocol)之前，请查看所需的库是否已被其他项目OSGi 化。一个很好的开始是查看 Apache ServiceMix 项目提供的 Bundle(它提供了一个 okhttp3 Bundle):

• https://repo1.maven.org/maven2/org/apache/servicemix/bundles/