我试图计算出我的
Java程序有多少内存可用.
我现在有这个实现：
我现在有这个实现：
long getAvailableMemory() {
Runtime runtime = Runtime.getRuntime();
long totalMemory = runtime.totalMemory();
long freeMemory = runtime.freeMemory();
long maxMemory = runtime.maxMemory();
long usedMemory = totalMemory - freeMemory;
long availableMemory = maxMemory - usedMemory;
return availableMemory;
}
是对的吗？有更简单/更准确的计算方法吗？看了别人的代码之后,我看到这样的东西有些不同：
long getAvailableMemory() {
long totalVmHeap = Runtime.getRuntime().totalMemory();
long freeVmHeap = Runtime.getRuntime().freeMemory();
long usedVmHeap = totalVmHeap - freeVmHeap;
long maxVmHeap = Runtime.getRuntime().maxMemory();
long availableVmHeap = maxVmHeap - usedVmHeap + freeVmHeap;
return availableVmHeap;
}
解决方法
你的解决方案对我来说是正确的(在下面评论来解释你正在计算的)：
long getAvailableMemory() {
Runtime runtime = Runtime.getRuntime();
long totalMemory = runtime.totalMemory(); // current heap allocated to the VM process
long freeMemory = runtime.freeMemory(); // out of the current heap,how much is free
long maxMemory = runtime.maxMemory(); // Max heap VM can use e.g. Xmx setting
long usedMemory = totalMemory - freeMemory; // how much of the current heap the VM is using
long availableMemory = maxMemory - usedMemory; // available memory i.e. Maximum heap size minus the current amount used
return availableMemory;
}
我不知道你的用例是什么,但是在堆内也有限制,你可能想看看PermGen大小：How do I programmatically find out my PermGen space usage?
