alpine常用于作为docker的基础镜像，因为它很小，功能精简，基本上没有啥漏洞，记录一下最近用alpine作为基础镜像构建java 8镜像 下面的问题在oracle jdk openjdk都会出现 。
错误一
java.lang.NoClassDefFoundError: Could not initialize class sun.awt.X11FontManager
这个错误一般出现在生成验证码绘制的时候，这个错误大概原因就是由于在alpine上太过于精简了，导致初始化FontManagerFactory工厂初始化失败，那么解决办法就是安装glibc。
网上有很多博主都只讲安装了glib.apk 核心包就行，其实这里需要安装3个包 以2.3.0为例 需要安装的包为
- https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.30-r0/glibc-2.30-r0.apk
- https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.30-r0/glibc-bin-2.30-r0.apk
- https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.30-r0/glibc-i18n-2.30-r0.apk
安装命令如下
apk --no-cache add libstdc++ ca-certificates bash wget wget -q -O /etc/apk/keys/sgerrand.rsa.pub https://alpine-pkgs.sgerrand.com/sgerrand.rsa.pub wget https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.30-r0/glibc-2.30-r0.apk wget https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.30-r0/glibc-bin-2.30-r0.apk wget https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.30-r0/glibc-i18n-2.30-r0.apk apk add glibc-2.30-r0.apk && apk add glibc-bin-2.30-r0.apk && apk add glibc-i18n-2.30-r0.apk
安装完后就没有问题了，测试方法 可以写一个main方法在容器中验证是否能执行通过Class.forName("sun.awt.X11FontManager");,当在验证码不可行环境的时候 报错的消息为
/usr/local/jdk1.8.0_301/jre/lib/amd64/libfontmanager.so: libgcc_s.so.1: cann......。
还有就是可以进入在运行中的容器直接安装 安装完成了之后基本上就没有问题了。
错误二
该错误在openJDK中出现过，OracleJDK没有出现。
error while loading shared libraries: libz.so.1: cannot open shared object file:
解决方式就安装zlib 安装命令如下
curl -Ls https://archive.archlinux.org/packages/z/zlib/zlib-1%3A1.2.9-1-x86_64.pkg.tar.xz -o libz.tar.xz && mkdir -p libz && tar -xf libz.tar.xz -C libz mv libz/usr/lib/libz.so* /usr/glibc-compat/lib rm -rf libz.tar.xz
安装好后 没有问题了
dragonwell openjdk Dockerfile
另贴上基于alpine的阿里dragonwell openjdk的Dockerfile
dragonwell JDK Dockerfile
FROM alpine:3.8
LABEL maintainer="xstao"
ENV TZ=Asia/Shanghai
RUN ln -snf /usr/share/zoneinfo/${TZ} /etc/localtime && \
echo ${TZ} > /etc/timezone
#mirrons aliun
RUN echo http://mirrors.aliyun.com/alpine/v3.10/main/ > /etc/apk/repositories && \
echo http://mirrors.aliyun.com/alpine/v3.10/community/ >> /etc/apk/repositories
RUN apk update && apk upgrade
#install glibc
RUN apk --no-cache add libstdc++ ca-certificates bash wget curl && \
wget -q -O /etc/apk/keys/sgerrand.rsa.pub https://alpine-pkgs.sgerrand.com/sgerrand.rsa.pub && \
wget https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.30-r0/glibc-2.30-r0.apk && \
wget https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.30-r0/glibc-bin-2.30-r0.apk && \
wget https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.30-r0/glibc-i18n-2.30-r0.apk && \
apk add glibc-2.30-r0.apk && apk add glibc-bin-2.30-r0.apk && apk add glibc-i18n-2.30-r0.apk && \
curl -Ls https://archive.archlinux.org/packages/z/zlib/zlib-1%3A1.2.9-1-x86_64.pkg.tar.xz -o libz.tar.xz && mkdir -p libz && tar -xf libz.tar.xz -C libz && \
mv libz/usr/lib/libz.so* /usr/glibc-compat/lib && \
rm glibc-2.30-r0.apk && rm glibc-bin-2.30-r0.apk && rm glibc-i18n-2.30-r0.apk && rm -rf /var/cache/apk/* && rm -rf libz/* && rm -rf libz.tar.xz
RUN apk add --update font-adobe-100dpi ttf-dejavu fontconfig
ENV JAVA_VERSION="jdk8u302-b01"
ENV JAVA_HOME="/usr/local/${JAVA_VERSION}"
ENV PATH="${JAVA_HOME}/bin:${PATH}"
#
WORKDIR /opt
RUN wget https://dragonwell.oss-cn-shanghai.aliyuncs.com/8.8.9/Alibaba_Dragonwell_8.8.9_x64_linux.tar.gz
RUN tar -zxf Alibaba_Dragonwell_8.8.9_x64_linux.tar.gz
RUN mv ${JAVA_VERSION} /usr/local
RUN rm -rf Alibaba_Dragonwell_8.8.9_x64_linux.tar.gz