解决方法：
配置文件中加入
<property name="activityFontName" value="宋体"/> <property name="labelFontName" value="宋体"/>
重新部署！
<bean id="processEngineConfiguration" class="org.activiti.spring.SpringProcessEngineConfiguration"><property name="dataSource" ref="dataSource"></property><property name="transactionManager" ref="transactionManager"></property><property name="databaseSchemaUpdate" value="true"></property><!-- 生成流程图的字体 --><property name="activityFontName" value="宋体"/><property name="labelFontName" value="宋体"/>
</bean>