-Xmx size您可以使用命令行参数配置最大堆大小。默认为 64mb。你看到的 1.9m 看起来很奇怪。这是 java 命令的 Oracle 文档: https ://docs.oracle.com/javase/8/docs/technotes/tools/windows/java.html具体来说:-Xmx大小Specifies the maximum size (in bytes) of the memory allocation pool in bytes. This value must be a multiple of 1024 and greater than 2 MB. Append the letter k or K to indicate kilobytes, m or M to indicate megabytes, g or G to indicate gigabytes. The default value is chosen at runtime based on system configuration. For server deployments, -Xms and -Xmx are often set to the same value. See the section "Ergonomics" in Java SE HotSpot Virtual Machine Garbage Collection Tuning Guide at http://docs.oracle.com/javase/8/docs/technotes/guides/vm/gctuning/index.html.The following examples show how to set the maximum allowed size of allocated memory to 80 MB using various units:-Xmx83886080-Xmx81920k-Xmx80mThe -Xmx option is equivalent to -XX:MaxHeapSize.