之前在非容器環(huán)境下啟用spring boot連接容器內(nèi)的mysql時沒問題，url如下：

jdbc:mysql://localhost:3306/database?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=CTT

然后切換成用容器啟用spring boot的時候翔悠，報(bào)如下錯誤：

caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

經(jīng)排查是因?yàn)閿?shù)據(jù)庫地址的問題。
因?yàn)橛萌萜鲉⒂胹pring boot的話，容器的localhost是本容器自身扳剿，因此此URL無法連接到mysql的容器，需要先找到mysql容器的IP地址昼激，可以用：

docker inspect mysql

查看mysql運(yùn)行的ip地址庇绽，下面截取了部分inspect后的內(nèi)容：

"NetworkSettings": {
            "Bridge": "",
            "SandboxID": "0c1d92762fc6ca2f74c1ef50924296778f9127c61ae3cdefd28e01150e43c5e0",
            "HairpinMode": false,
            "LinkLocalIPv6Address": "",
            "LinkLocalIPv6PrefixLen": 0,
            "Ports": {
                "3306/tcp": [
                    {
                        "HostIp": "0.0.0.0",
                        "HostPort": "3306"
                    }
                ]
            },
            "SandboxKey": "/var/run/docker/netns/0c1d92762fc6",
            "SecondaryIPAddresses": null,
            "SecondaryIPv6Addresses": null,
            "EndpointID": "da20b50cae96f425944364e876036ebfe0a55d16c2e5011a6108d999403c08c6",
            "Gateway": "172.17.0.1",
            "GlobalIPv6Address": "",
            "GlobalIPv6PrefixLen": 0,
            "IPAddress": "172.17.0.2",
            "IPPrefixLen": 16,
            "IPv6Gateway": "",
            "MacAddress": "02:42:ac:11:00:02",
            "Networks": {
                "bridge": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "945bdd4c50acef80817597aa8014c0f9698791387ebac0167d330ecbfe611706",
                    "EndpointID": "da20b50cae96f425944364e876036ebfe0a55d16c2e5011a6108d999403c08c6",
                    "Gateway": "172.17.0.1",
                    "IPAddress": "172.17.0.2",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:00:02",
                    "DriverOpts": null
                }
            }
        }
    }

可以看到mysql運(yùn)行時，分配的IP地址是172.17.0.2橙困，因此修改URL連接為：

jdbc:mysql://172.17.0.2:3306/database?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=CTT

就可以正常運(yùn)行了瞧掺。