获取对象占用内存

1. 添加依赖

   <dependency><groupId>org.apache.lucene</groupId><artifactId>lucene-core</artifactId><version>4.0.0</version>
   </dependency>
   

2. 添加vm启动参数

   --add-opens java.base/java.lang=ALL-UNNAMED --add-opens java.base/java.util=ALL-UNNAMED --add-opens java.base/java.nio=ALL-UNNAMED --add-opens java.base/sun.nio.ch=ALL-UNNAMED
   

3. 编写测试代码

   public static void main(String[] args) throws Exception {List<ChannelUserDTO> list = new ArrayList<>() ;for (int i = 0; i < 1000000; i++) {list.add(new ChannelUserDTO()) ;}log.info("size 2: {}", RamUsageEstimator.humanSizeOf(list));
   }