在停tomcat後，重新啓動tomcat 報以下錯誤：
tomcat 文件下bin目錄裏的hs_err_pid14967.log 報錯內容
#
# There is insufficient memory for the Java Runtime Environment to continue.
# Native memory allocation (mmap) failed to map 134217728 bytes for committing reserved memory.
# Possible reasons:
# The system is out of physical RAM or swap space
# In 32 bit mode, the process size limit was hit
# Possible solutions:
# Reduce memory load on the system
# Increase physical memory or swap space
# Check if swap backing store is full
# Use 64 bit Java on a 64 bit OS
# Decrease Java heap size (-Xmx/-Xms)
# Decrease number of Java threads
# Decrease Java thread stack sizes (-Xss)
# Set larger code cache with -XX:ReservedCodeCacheSize=
# This output file may be truncated or incomplete.
#
# Out of Memory Error (os_linux.cpp:2627), pid=14967, tid=0x00007f7f44bdd700
#
# JRE version: Java(TM) SE Runtime Environment (8.0_111-b14) (build 1.8.0_111-b14)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.111-b14 mixed mode linux-amd64 compressed oops)
# Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
#
在控制檯中報錯中顯示內存溢出
一開始以爲是分配內存不足，經過網上查找，最後發現是因爲tomcat的端口被佔用，在停tomcat時，進程沒有 被殺死導致的
這是就需要去殺死進程才能啓動tomcat
1、先查看端口被佔用情況：
netstat -apn|grep 80
確實是被佔用了
2、 確定進程號
通過命令：ps -ef | grep tomcat 如下圖
root 後面的就是進程號
使用以下命令查看詳細信息：
ps -aux|grep <進程號>
eg: ps -aux | grep 1091
3. 殺掉該進程
kill -9 進程號
殺掉所有的進程後，就可以啓動tomcat了
注：所有的命令在tomcat的bin路徑下執行