@Configuration
public class ActivitiConfiguration {

    @Bean
    public ProcessEngineConfigurationConfigurer getProcessEngineConfigurationConfigurerImpl() {
        return new ProcessEngineConfigurationConfigurerImpl();
    }

    public static class ProcessEngineConfigurationConfigurerImpl implements ProcessEngineConfigurationConfigurer {
        @Override
        public void configure(SpringProcessEngineConfiguration configuration) {
            configuration.setActivityFontName("宋体");
            configuration.setAnnotationFontName("宋体");
            configuration.setLabelFontName("宋体");
        }
    }
}

代码中，我使用的字体是宋体，window(C:\Windows\Fonts)的simsun.tcc，将simsun.tcc文件拷贝到Dockerfile文件同级目录下，修改Dockerfile文件新增如下命令

# docker activiti 流程图中文乱码处理
# 将字体simsun.ttc 放到docker镜像的/usr/share/fonts目录下
COPY simsun.ttc  /usr/share/fonts/simsun.ttc

重新制作镜像运行新版本容器，生成的流程图中文字体即可正常显示