Dockerfile中JAVA_HOME配置无效致sdkmanager执行失败求助

我是Docker新手，在Dockerfile中配置JAVA_HOME后仍无法被识别。执行RUN /opt/Android/cmdline-tools/latest/bin/sdkmanager --update时出现以下错误：

ERROR: JAVA_HOME is set to an invalid directory: /usr/lib/jvm/java-8-openjdk-amd64
Please set the JAVA_HOME variable in your environment to match the location of your Java installation.

同时构建返回退出码1：executor failed running [/bin/sh -c /opt/Android/cmdline-tools/latest/bin/sdkmanager --update]: exit code: 1

我不清楚JDK实际安装路径，也不知道如何在Dockerfile中确认该路径，尝试在构建时echo JAVA_HOME也没有结果，附上我的Dockerfile代码：

FROM node:12.12.0

ARG CMDLINE_TOOLS_VERSION=7583922
ARG ANDROID_BUILD_TOOLS=30.0.3

RUN apt-get -qqy update \
    && apt-get -qqy install \
    python-dev \
    --no-install-recommends

RUN apt-get install -y software-properties-common gcc
RUN apt-get update && apt-get install -y  python3-pip
RUN pip3 install awscli
RUN apt-get install -y jq
RUN mkdir -p /usr/share/man/man1 /usr/share/man/man2
RUN apt-get update && apt-get install -y --no-install-recommends openjdk-8-jdk && apt-get clean;

ENV JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64
ENV PATH=$PATH:$JAVA_HOME/bin

RUN wget -q https://services.gradle.org/distributions/gradle-4.5.1-bin.zip && unzip gradle-4.5.1-bin.zip -d /opt && rm gradle-4.5.1-bin.zip

ENV GRADLE_HOME=/opt/gradle-4.5.1
ENV PATH=$PATH:/opt/gradle-4.5.1/bin

RUN wget https://dl.google.com/android/repository/commandlinetools-linux-${CMDLINE_TOOLS_VERSION}_latest.zip
RUN mkdir -p /opt/Android/cmdline-tools
RUN  unzip commandlinetools-linux-7583922_latest.zip -d /opt/Android/cmdline-tools
RUN mv /opt/Android/cmdline-tools/cmdline-tools /opt/Android/cmdline-tools/latest

ENV ANDROID_HOME=/opt/Android
ENV PATH="$ANDROID_HOME/emulator:$ANDROID_HOME/tools:$ANDROID_HOME/tools/bin \
:$ANDROID_HOME/cmdline-tools/latest:$ANDROID_HOME/cmdline-tools/latest/bin:$ANDROID_HOME/platform-tools:$PATH"

RUN /opt/Android/cmdline-tools/latest/bin/sdkmanager --update
RUN /opt/Android/cmdline-tools/latest/bin/sdkmanager --list
RUN /opt/Android/cmdline-tools/latest/bin/sdkmanager --list | grep build-tools
RUN echo y | /opt/Android/cmdline-tools/latest/bin/sdkmanager "build-tools;${ANDROID_BUILD_TOOLS}" "platform-tools" "platforms;android-30" "tools" >/dev/null
RUN yes | /opt/Android/cmdline-tools/latest/bin/sdkmanager --licenses

CMD ["yarn", "start"]

解决方案 #

1. 确认JDK实际安装路径 #

在Dockerfile中安装完JDK后，添加以下命令，构建时就能看到系统中真实存在的JVM路径：

RUN apt-get update && apt-get install -y --no-install-recommends openjdk-8-jdk && apt-get clean;
# 添加这两行查看路径
RUN ls -la /usr/lib/jvm/
RUN update-alternatives --list java

构建镜像时，这两个命令会输出关键信息：

• ls命令会列出/usr/lib/jvm/下的所有目录，确认java-8-openjdk-amd64是否存在
• update-alternatives命令会输出Java可执行文件的完整路径，比如/usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java，对应的JAVA_HOME就是去掉/jre/bin/java后的部分，即/usr/lib/jvm/java-8-openjdk-amd64

2. 验证JAVA_HOME设置是否生效 #

设置ENV后添加验证命令，确保环境变量正确加载且Java环境正常：

ENV JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64
ENV PATH=$PATH:$JAVA_HOME/bin
# 添加验证命令
RUN echo "JAVA_HOME is $JAVA_HOME"
RUN java -version
RUN javac -version

如果javac命令报错，说明安装的是JRE而非JDK，需要重新执行apt-get install -y openjdk-8-jdk命令。

3. 优化后的完整Dockerfile #

以下是调整后的Dockerfile，合并冗余命令减少镜像层级，同时加入路径验证步骤：

FROM node:12.12.0

ARG CMDLINE_TOOLS_VERSION=7583922
ARG ANDROID_BUILD_TOOLS=30.0.3

RUN apt-get -qqy update \
    && apt-get -qqy install \
    python-dev software-properties-common gcc python3-pip jq \
    --no-install-recommends \
    && pip3 install awscli \
    && mkdir -p /usr/share/man/man1 /usr/share/man/man2 \
    && apt-get update && apt-get install -y --no-install-recommends openjdk-8-jdk \
    && apt-get clean && rm -rf /var/lib/apt/lists/*

# 查看JVM路径并验证JAVA_HOME
RUN ls -la /usr/lib/jvm/
RUN update-alternatives --list java
ENV JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64
ENV PATH=$PATH:$JAVA_HOME/bin
RUN echo "JAVA_HOME is $JAVA_HOME"
RUN java -version
RUN javac -version

RUN wget -q https://services.gradle.org/distributions/gradle-4.5.1-bin.zip && unzip gradle-4.5.1-bin.zip -d /opt && rm gradle-4.5.1-bin.zip

ENV GRADLE_HOME=/opt/gradle-4.5.1
ENV PATH=$PATH:/opt/gradle-4.5.1/bin

RUN wget https://dl.google.com/android/repository/commandlinetools-linux-${CMDLINE_TOOLS_VERSION}_latest.zip \
    && mkdir -p /opt/Android/cmdline-tools \
    && unzip commandlinetools-linux-7583922_latest.zip -d /opt/Android/cmdline-tools \
    && mv /opt/Android/cmdline-tools/cmdline-tools /opt/Android/cmdline-tools/latest \
    && rm commandlinetools-linux-7583922_latest.zip

ENV ANDROID_HOME=/opt/Android
ENV PATH="$ANDROID_HOME/emulator:$ANDROID_HOME/tools:$ANDROID_HOME/tools/bin \
:$ANDROID_HOME/cmdline-tools/latest:$ANDROID_HOME/cmdline-tools/latest/bin:$ANDROID_HOME/platform-tools:$PATH"

RUN /opt/Android/cmdline-tools/latest/bin/sdkmanager --update \
    && /opt/Android/cmdline-tools/latest/bin/sdkmanager --list | grep build-tools \
    && echo y | /opt/Android/cmdline-tools/latest/bin/sdkmanager "build-tools;${ANDROID_BUILD_TOOLS}" "platform-tools" "platforms;android-30" "tools" >/dev/null \
    && yes | /opt/Android/cmdline-tools/latest/bin/sdkmanager --licenses

CMD ["yarn", "start"]

内容的提问来源于stack exchange，提问作者anonymoose