使用Gradle构建Apache POI 5.2.4时Java工具链匹配失败求助

问题背景 #

此前使用Apache工具包只需导入附带jar即可使用，但Apache POI 5.2.4需通过Gradle构建。在Eclipse 2022-03中通过「导入→现有Gradle项目」构建，以及命令行执行构建均失败，报错如下：

提供的阶段操作执行失败，配置项目':poi'时出现问题。评估项目':poi'时出错，无法计算任务':poi:compileTestJava'的'javaCompiler'属性值。未找到符合请求规格{languageVersion=8, vendor=any, implementation=vendor-specific}的工具链（适用于WINDOWS x86_64系统）。本地未安装匹配的工具链，且未配置工具链下载仓库。

未修改Apache提供的build.gradle，其工具链配置代码如下：

java {
    toolchain {
        languageVersion = JavaLanguageVersion.of(jdkVersion)
        if (jdkVendor != '') vendor = JvmVendorSpec.matching(jdkVendor)
    }
    withJavadocJar()
    withSourcesJar()
}

命令行执行gradle.bat的完整输出：

poi-src-5.2.4-20230921-5.2.4>gradle.bat
Configuration on demand is an incubating feature.

> Configure project :
Trying to override old definition of datatype junit

FAILURE: Build failed with an exception.

* Where:
Build file 'C:\Users\x\eclipse-workspace\poi-src-5.2.4-20230921-5.2.4\poi\build.gradle' line: 82

* What went wrong:
A problem occurred evaluating project ':poi'.
> Failed to calculate the value of task ':poi:compileTestJava' property 'javaCompiler'.
   > No matching toolchains found for requested specification: {languageVersion=8, vendor=any, implementation=vendor-specific} for WINDOWS on x86_64.
      > No locally installed toolchains match and toolchain download repositories have not been configured.

* Try:
> Learn more about toolchain auto-detection at https://docs.gradle.org/8.4/userguide/toolchains.html#sec:auto_detection.
> Learn more about toolchain repositories at https://docs.gradle.org/8.4/userguide/toolchains.html#sub:download_repositories.
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.
> Get more help at https://help.gradle.org.

Deprecated Gradle features were used in this build, making it incompatible with Gradle 9.0.

You can use '--warning-mode all' to show the individual deprecation warnings and determine if they come from your own scripts or plugins.

For more on this, please refer to https://docs.gradle.org/8.4/userguide/command_line_interface.html#sec:command_line_warnings in the Gradle documentation.

BUILD FAILED in 1s

问题原因 #

1. POI 5.2.4的构建脚本默认指定Java 8作为编译测试代码的工具链版本，而你本地仅安装了Java 21，且未配置Gradle自动下载对应JDK的仓库。
2. 尝试安装旧版Java时，可能因环境变量配置错误、JDK安装路径包含特殊字符等，导致Gradle无法识别本地工具链。

解决方法 #

方法一：安装Java 8并配置Gradle识别 #

1. 下载并安装Java 8 JDK（需为JDK而非JRE），安装路径避免中文或特殊字符。
2. 让Gradle检测到Java 8：
   • 设置环境变量JAVA_HOME_8指向Java 8的安装目录；
   • 或临时将Java 8的bin目录加入系统PATH（仅临时解决，不推荐长期使用）。
3. 重新执行gradle.bat即可。

方法二：修改构建脚本适配现有Java版本 #

若不想安装Java 8，可修改POI的构建配置：

1. 在POI源码根目录找到gradle.properties文件，将jdkVersion的值从8改为21。
2. 若修改后出现测试代码兼容性问题，可跳过测试任务构建核心jar：

gradle.bat build -x test

内容的提问来源于stack exchange，提问作者EngineerWithJava54321