如何将第 3 方库添加到 Android AOSP 构建中？

我正在尝试将 Jackson JSON 库添加到我的 AOSP 项目中。我可以编译我的项目并将其刷新到手机，但出现运行时错误：

E/JavaBinder( 1689): java.lang.NoClassDefFoundError: Failed resolution of: Lcom/fasterxml/jackson/core/JsonFactory;
...
E/JavaBinder( 1689): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.fasterxml.jackson.core.JsonFactory" on path: DexPathList[[zip file "/system/framework/guice.jar", zip file "/system/framework/beanshell.jar", zip file "/system/framework/services.jar", zip file "/system/framework/ethernet-service.jar", zip file "/system/framework/wifi-service.jar"],nativeLibraryDirectories=[/vendor/lib, /system/lib]]

我尝试过从源代码和 jar 中包含 Jackson。以下是我的 Android.mk 文件：

来源 Android.mk

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_SRC_FILES := $(call all-java-files-under,.)
LOCAL_MODULE_TAGS := optional
LOCAL_MODULE:= com.fasterxml.jackson.core
include $(BUILD_JAVA_LIBRARY)

# Copy XML to /system/etc/permissions/
include $(CLEAR_VARS)
LOCAL_MODULE_TAGS := optional
LOCAL_MODULE := com.fasterxml.jackson.core.xml
LOCAL_MODULE_CLASS := ETC
LOCAL_MODULE_PATH := $(TARGET_OUT_ETC)/permissions
LOCAL_SRC_FILES := $(LOCAL_MODULE)
include $(BUILD_PREBUILT)

SOURCE com.fasterxml.jackson.core.xml（上面提到过）

<?xml version="1.0" encoding="utf-8"?>
<permissions>
    <library name="com.fasterxml.jackson.core.xml"
        file="/system/framework/com.fasterxml.jackson.jar" />
</permissions>

JAR Android.mk

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := jackson
LOCAL_MODULE_TAGS := optional
LOCAL_SRC_FILES := jackson-core-2.5.0.jar
LOCAL_MODULE_CLASS := JAVA_LIBRARIES
LOCAL_MODULE_SUFFIX := $(COMMON_JAVA_PACKAGE_SUFFIX)
include $(BUILD_PREBUILT)

我还添加了一个jackson条目为 inLOCAL_JAVA_LIBRARIES :=Android.mk 文件中我想使用 Jackson 的部分（frameworks/base/services）。无论我尝试过什么，我都会得到一个ClassNotFoundException.

我缺少什么？我做了什么不必要的事吗？

包含第 3 方库从源头:

1. 将库的源代码复制到以下目录中$ANDROID_BUILD_TOP/external/ (ex: $ANDROID_BUILD_TOP/external/jackson)

2. 创建一个Android.mk文件，并将其放在库的文件夹中（例如：$ANDROID_BUILD_TOP/external/jackson/Android.mk

   Android.mk 的内容:

   # required (setup the build environment)
   LOCAL_PATH := $(call my-dir)
   include $(CLEAR_VARS)
   
   # optional step to automate some pre-compilation steps for this library
   # run `mvn generate-sources` before we compile
   $(info $(shell (mvn generate-sources -f $(LOCAL_PATH)/pom.xml)))
   
   # required (the name of the library we are building)
   LOCAL_MODULE := jackson
   
   # required (paths to all directories that include source code)
   # note the difference between the := (first line) and += (every other line)
   LOCAL_SRC_FILES := $(call all-java-files-under, src/main)
   LOCAL_SRC_FILES += $(call all-java-files-under, target/generated-sources)
   
   # required (tell the build system what kind of thing we are building)
   include $(BUILD_JAVA_LIBRARY)
   

3. 将库添加到PRODUCT_BOOT_JARS你的部分mk文件。您编辑哪个文件取决于您正在构建的内容（例如：build/target/product/core_minimal.mk)

   Original

   PRODUCT_BOOT_JARS := \
       okhttp \
       core-junit \
       bouncycastle \
       ext \
       gson
   

   Modified

   PRODUCT_BOOT_JARS := \
       okhttp \
       core-junit \
       bouncycastle \
       ext \
       gson \
       jackson
   

4. 对于每个子模块您的 AOSP 项目（例如：frameworks/base), 您想要访问图书馆，找到 makefile（例如：$ANDROID_BUILD_TOP/frameworks/base/Android.mk并将您的库的条目添加到LOCAL_JAVA_LIBRARIES线。例子：

   Original

   LOCAL_JAVA_LIBRARIES := guice gson
   

   Modified

   LOCAL_JAVA_LIBRARIES := guice gson jackson
   

5. 编译您的项目。