线上环境Excel导出报错，测试环境、本地环境都没问题，报错内容如下：
 

java.lang.NullPointerException: null
        at sun.awt.FontConfiguration.getVersion(FontConfiguration.java:1264)
        at sun.awt.FontConfiguration.readFontConfigFile(FontConfiguration.java:219)
        at sun.awt.FontConfiguration.init(FontConfiguration.java:107)
        at sun.awt.X11FontManager.createFontConfiguration(X11FontManager.java:774)
        at sun.font.SunFontManager$2.run(SunFontManager.java:441)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.font.SunFontManager.<init>(SunFontManager.java:386)
        at sun.awt.FcFontManager.<init>(FcFontManager.java:35)
        at sun.awt.X11FontManager.<init>(X11FontManager.java:57)
        at sun.reflect.GeneratedConstructorAccessor262.newInstance(Unknown Source)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        at java.lang.Class.newInstance(Class.java:442)
        at sun.font.FontManagerFactory$1.run(FontManagerFactory.java:83)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.font.FontManagerFactory.getInstance(FontManagerFactory.java:74)
        at java.awt.Font.getFont2D(Font.java:491)
        at java.awt.Font.canDisplayUpTo(Font.java:2064)
        at java.awt.font.TextLayout.singleFont(TextLayout.java:470)
        at java.awt.font.TextLayout.<init>(TextLayout.java:531)
        at org.apache.poi.ss.util.SheetUtil.getDefaultCharWidth(SheetUtil.java:273)

原因：这个错误是由于生产环境中缺少字体配置导致的。NullPointerException 发生在 Java 试图获取字体配置时，特别是在使用 Apache POI 进行 Excel 导出时。
 

解决方法：

在生产环境服务器上安装字体包
 

# CentOS/RHEL
yum install fontconfig -y

# Ubuntu/Debian
apt-get update && apt-get install fontconfig -y

# 安装后刷新字体缓存
fc-cache -fv

# 然后重启项目

最后需要然后重启项目。