在 java 9 中使用 jdeps 为自动模块创建模块信息 [英] creating module-info for automatic modules with jdeps in java 9

问题描述

我有 3 罐 jackson 库

I have 3 jar of jackson library

1. jackson-core-2.8.10.jar
2. jackson-annotations-2.8.0.jar
3. jackson-databind-2.8.10.jar

我成功地为 core 和 annotation 创建了 module-info.java 并使用 jdeps 将它们转换为 Named maodule.

I created module-info.java for both core and annotation successfully and converted them to Named maodule using jdeps.

对于 databind ，我尝试了以下命令:

for databind , I tried following command:

jdeps --generate-module-info .--module-path %JAVA_HOME%jomds;jackson.core;jackson.annotations existingmodsjackson-databind-2.8.10.jar

jdeps --generate-module-info . --module-path %JAVA_HOME%jomds;jackson.core;jackson.annotations existingmodsjackson-databind-2.8.10.jar

现在出现以下错误:

Missing dependence: .jackson.databindmodule-info.java not generated
Error: missing dependencies
   com.fasterxml.jackson.databind.AnnotationIntrospector -> com.fasterxml.jackson.annotation.JsonCreator       not found
   com.fasterxml.jackson.databind.AnnotationIntrospector -> com.fasterxml.jackson.annotation.JsonCreator$Mode  not found
   com.fasterxml.jackson.databind.AnnotationIntrospector -> com.fasterxml.jackson.annotation.JsonFormat        not found
   com.fasterxml.jackson.databind.AnnotationIntrospector -> com.fasterxml.jackson.annotation.JsonFormat$Value  not found
   com.fasterxml.jackson.databind.AnnotationIntrospector -> com.fasterxml.jackson.annotation.JsonIgnoreProperties not found
   com.fasterxml.jackson.databind.AnnotationIntrospector -> com.fasterxml.jackson.annotation.JsonIgnoreProperties$Value not found.

如何为 jackson-databind 生成 module-info.java ?

How can I generate module-info.java for jackson-databind ?

推荐答案

简短的回答是，是的，您必须将库转换为显式模块.

The short answer is that, yes, you'll have to convert the libraries to explicit modules.

jlink 工具旨在提供仅包含所需模块的修剪过的二进制图像.问题是自动模块可以访问可以读取所有 JDK 模块的类路径(也称为未命名模块).所以什么都不会被修剪.

The jlink tool is intended to provide a trimmed binary image that has only the required modules. The issue is that automatic modules have access to the classpath (aka the unnamed module) which can read all JDK modules. So nothing would be trimmed.

这个帖子 也说明了这一点，带有指向 YouTube 视频的链接.

This thread states this as well, with a link to a YouTube video.

这个例子转换commons-lang3-3.5.jar 到 jlink 演示的显式模块.

This example converts commons-lang3-3.5.jar to an explict module for a jlink demo.

编辑:更具体地说，这里是一个例子 脚本，按顺序将 jackson-core、jackson-annotations 和 jackson-databind 遗留 jar 转换为模块化 jar.

Edit: to be more specific, here is an example script that converts, in order, jackson-core, jackson-annotations, and jackson-databind legacy jars to modular jars.

想法是:

• 在旧 jar 上运行 jdeps --generate-module-info
• 将遗留的 jar 解压到一个文件夹中，从上面添加 module-info.java，重新编译并重新压缩

• run jdeps --generate-module-info on the legacy jar
• unzip the legacy jar into a folder, add module-info.java from above, re-compile, and re-zip

诀窍是具有依赖项的模块化 jar 将需要这些依赖项作为命令行参数.例如，这里是 jackson-databind(有些抽象):

The trick is that modular jars with dependencies will require those dependencies as command-line parameters. For example, here is jackson-databind (abstracted somewhat):

# here, jackson-core and jackson-annotations have been built
# jackson-databind 

jdeps --module-path $ROOT_DIR/modules 
--add-modules jackson.annotations,jackson.core 
--generate-module-info work $JACKSON_DATABIND_JAR

javac --module-path $ROOT_DIR/modules 
--add-modules jackson.annotations,jackson.core 
-d $ROOT_DIR/classes module-info.java

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