neutron创建network执行的那些命令
当搭建完openstack之后，在创建instance之前，第一件事情就是创建network，一个经典的流程如下：
TENANT_NAME="openstack"
TENANT_NETWORK_NAME="openstack-net"
TENANT_SUBNET_NAME="${TENANT_NETWORK_NAME}-subnet"
TENANT_ROUTER_NAME="openstack-router"
FIXED_RANGE="NEUTRON_FIXED_RANGE"
NETWORK_GATEWAY="NEUTRON_NETWORK_GATEWAY"
PUBLIC_GATEWAY="NEUTRON_PUBLIC_GATEWAY"
PUBLIC_RANGE="NEUTRON_PUBLIC_RANGE"
PUBLIC_START="NEUTRON_PUBLIC_START"
PUBLIC_END="NEUTRON_PUBLIC_END"
(1) 创建private network和subnet
TENANT_ID=$(keystone tenant-list | grep " $TENANT_NAME " | awk '{print $2}')
TENANT_NET_ID=$(neutron net-create --tenant_id $TENANT_ID $TENANT_NETWORK_NAME --provider:network_type gre --provider:segmentation_id 1 | grep " id " | awk '{print $4}')
TENANT_SUBNET_ID=$(neutron subnet-create --tenant_id $TENANT_ID --ip_version 4 --name $TENANT_SUBNET_NAME $TENANT_NET_ID $FIXED_RANGE --gateway $NETWORK_GATEWAY --dns_nameservers list=true 8.8.8.8 | grep " id " | awk '{print $4}')
当仅有private network的时候，会对这个private network创建一个DHCP Server
所以DHCP Agent会执行下面的命令：
ip netns exec qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0 ip -o link show tap452bdfab-31
这个命令试图从dhcp的namespace里面查找dhcp的网卡，但是很可惜找不到，返回error
Cannot open network namespace "qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0": No such file or directory
于是试图创建dhcp server的网卡，这个网卡会attach到br-int上，所以先查看br-int
ip -o link show br-int
如果br-int没有问题，于是创建dhcp server的网卡，并且attach到br-int上
ovs-vsctl -- --if-exists del-port tap452bdfab-31 -- add-port br-int tap452bdfab-31 -- set Interface tap452bdfab-31 type=internal -- set Interface tap452bdfab-31 external-ids:iface-id=452bdfab-3152-44d0-bd9c-40c94a6f8640 -- set Interface tap452bdfab-31 external-ids:iface-status=active -- set Interface tap452bdfab-31 external-ids:attached-mac=fa:16:3e:d7:08:67
为网卡设置mac
ip link set tap452bdfab-31 address fa:16:3e:d7:08:67
查看当前存在的namespace
ip -o netns list
返回
qrouter-26a45e0e-a58a-443b-a972-d62c0c5a1323
qdhcp-760d2c5e-4938-49b0-bffe-c77c5b141d18
发现没有这个dhcp所对应的namespace，需要创建一个
ip netns add qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0
将io网卡设置为up
ip netns exec qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0 ip link set lo up
将新建的dhcp server的网卡放在这个namespace里面
ip link set tap452bdfab-31 netns qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0
将DHCP server的网卡设置为up
ip netns exec qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0 ip link set tap452bdfab-31 up
查看这个网卡的ip地址
ip netns exec qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0 ip addr show tap452bdfab-31 permanent scope global
为这个网卡配置ip地址
ip netns exec qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0 ip -4 addr add 192.168.10.3/24 brd 192.168.10.255 scope global dev tap452bdfab-31
ip netns exec qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0 ip -4 addr add 169.254.169.254/16 brd 169.254.255.255 scope global dev tap452bdfab-31
第一个地址是dhcp server的地址，第二个地址是metadata server的地址
查看路由表
ip netns exec qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0 ip route list dev tap452bdfab-31
169.254.0.0/16 proto kernel scope link src 169.254.169.254
192.168.10.0/24 proto kernel scope link src 192.168.10.3
添加路由表
ip netns exec qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0 ip route replace default via 192.168.10.1 dev tap452bdfab-31
查看网卡的配置
ip netns exec qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0 ip addr show tap452bdfab-31
232: tap452bdfab-31: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default
link/ether fa:16:3e:d7:08:67 brd ff:ff:ff:ff:ff:ff
inet 192.168.10.3/24 brd 192.168.10.255 scope global tap452bdfab-31
valid_lft forever preferred_lft forever
inet 169.254.169.254/16 brd 169.254.255.255 scope global tap452bdfab-31
valid_lft forever preferred_lft forever
inet6 fe80::f816:3eff:fed7:867/64 scope link tentative
valid_lft forever preferred_lft forever
启动dhcp server
ip netns exec qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0 env NEUTRON_NETWORK_ID=66b9930b-2871-414c-8c6f-991a6a8cffe0 dnsmasq --no-hosts --no-resolv --strict-order --bind-interfaces --interface=tap452bdfab-31 --except-interface=lo --pid-file=/var/lib/neutron/dhcp/66b9930b-2871-414c-8c6f-991a6a8cffe0/pid --dhcp-hostsfile=/var/lib/neutron/dhcp/66b9930b-2871-414c-8c6f-991a6a8cffe0/host --addn-hosts=/var/lib/neutron/dhcp/66b9930b-2871-414c-8c6f-991a6a8cffe0/addn_hosts --dhcp-optsfile=/var/lib/neutron/dhcp/66b9930b-2871-414c-8c6f-991a6a8cffe0/opts --leasefile-ro --dhcp-range=set:tag0,192.168.10.0,static,86400s --dhcp-lease-max=256 --conf-file= --domain=openstacklocal
启动metadata proxy
ip netns exec qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0 neutron-ns-metadata-proxy --pid_file=/var/lib/neutron/external/pids/66b9930b-2871-414c-8c6f-991a6a8cffe0.pid --metadata_proxy_socket=/var/lib/neutron/metadata_proxy --network_id=66b9930b-2871-414c-8c6f-991a6a8cffe0 --state_path=/var/lib/neutron --metadata_port=80 --debug --verbose --log-file=neutron-ns-metadata-proxy-66b9930b-2871-414c-8c6f-991a6a8cffe0.log --log-dir=/var/log/neutron
最后查看一下网卡配置
ip netns exec qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0 ip addr show tap452bdfab-31
kill -HUP 17666
这个PID是什么呢？
# ps aux | grep 17666
nobody 17666 0.0 0.0 28204 1112 ? S Jul14 0:00 dnsmasq --no-hosts --no-resolv --strict-order --bind-interfaces --interface=tap452bdfab-31 --except-interface=lo --pid-file=/var/lib/neutron/dhcp/66b9930b-2871-414c-8c6f-991a6a8cffe0/pid --dhcp-hostsfile=/var/lib/neutron/dhcp/66b9930b-2871-414c-8c6f-991a6a8cffe0/host --addn-hosts=/var/lib/neutron/dhcp/66b9930b-2871-414c-8c6f-991a6a8cffe0/addn_hosts --dhcp-optsfile=/var/lib/neutron/dhcp/66b9930b-2871-414c-8c6f-991a6a8cffe0/opts --leasefile-ro --dhcp-range=set:tag0,192.168.10.0,static,86400s --dhcp-lease-max=256 --conf-file= --domain=openstacklocal
原来是我们的dhcp server
这个命令的作用是：如果想要更改配置而不需停止并重新启动服务，请使用该命令。在对配置文件作必要的更改后，发出该命令以动态更新服务配置。
最后查看一下路由配置
ip netns exec qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0 ip route list dev tap452bdfab-31
(2) 创建一个router，并且和private network相连
ROUTER_ID=$(neutron router-create --tenant_id $TENANT_ID $TENANT_ROUTER_NAME | grep " id " | awk '{print $4}')
neutron router-interface-add $ROUTER_ID $TENANT_SUBNET_ID
查看br-ex
ip -o link show br-ex
59: br-ex: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default
link/ether a0:48:1c:ab:df:b5 brd ff:ff:ff:ff:ff:ff
查看所有的namespace
ip -o netns list
qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0
qrouter-26a45e0e-a58a-443b-a972-d62c0c5a1323
qdhcp-760d2c5e-4938-49b0-bffe-c77c5b141d18
发现没有这个router的namespace，创建一个
ip netns add qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82
将io网卡设为up
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 ip link set lo up
这是一个router，所以enable ip forward
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 sysctl -w net.ipv4.ip_forward=1
初始化iptables
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 iptables-save –c
# Generated by iptables-save v1.4.21 on Thu Jul 17 01:37:57 2014
*nat
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
COMMIT
# Completed on Thu Jul 17 01:37:57 2014
# Generated by iptables-save v1.4.21 on Thu Jul 17 01:37:57 2014
*mangle
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
COMMIT
# Completed on Thu Jul 17 01:37:57 2014
# Generated by iptables-save v1.4.21 on Thu Jul 17 01:37:57 2014
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
COMMIT
# Completed on Thu Jul 17 01:37:57 2014
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 iptables-restore –c
启动metadata proxy
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 neutron-ns-metadata-proxy --pid_file=/var/lib/neutron/external/pids/d62d417d-2005-46d7-a83b-b1e5c0a36d82.pid --metadata_proxy_socket=/var/lib/neutron/metadata_proxy --router_id=d62d417d-2005-46d7-a83b-b1e5c0a36d82 --state_path=/var/lib/neutron --metadata_port=9697 --debug --verbose --log-file=neutron-ns-metadata-proxy-d62d417d-2005-46d7-a83b-b1e5c0a36d82.log --log-dir=/var/log/neutron
查看router的网卡
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 ip -o link show qr-29003a09-e7
但是网卡不存在
Device "qr-29003a09-e7" does not exist.
查看br-int，router的网卡会attach到这个网卡上
ip -o link show br-int
58: br-int: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default
link/ether 0a:9b:c6:54:ef:46 brd ff:ff:ff:ff:ff:ff
创建router的网卡，并且attach到br-int
ovs-vsctl -- --if-exists del-port qr-29003a09-e7 -- add-port br-int qr-29003a09-e7 -- set Interface qr-29003a09-e7 type=internal -
- set Interface qr-29003a09-e7 external-ids:iface-id=29003a09-e787-49dd-b5f4-11ad107159c7 -- set Interface qr-29003a09-e7 external-ids:iface-status=active -- set Interface qr-29003a09-e7 external-ids:attached-mac=fa:16:3e:84:6e:cc
设置router网卡的mac
ip link set qr-29003a09-e7 address fa:16:3e:84:6e:cc
查看所有的namespace
ip -o netns list
qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82
qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0
qrouter-26a45e0e-a58a-443b-a972-d62c0c5a1323
qdhcp-760d2c5e-4938-49b0-bffe-c77c5b141d18
有这个router的namespace
将这个网卡放在这个namespace里面
ip link set qr-29003a09-e7 netns qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82
将router的网卡设为up
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 ip link set qr-29003a09-e7 up
查看网卡的地址
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 ip addr show qr-29003a09-e7 permanent scope global
设置网卡的地址
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 ip -4 addr add 192.168.10.1/24 brd 192.168.10.255 scope global dev qr-2
9003a09-e7
查看所有的网卡
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 ip -o -d link list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 promiscuity 0
241: qr-29003a09-e7: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default
link/ether fa:16:3e:84:6e:cc brd ff:ff:ff:ff:ff:ff promiscuity 1
(3) 创建外网，并且连接到router
neutron net-create public --router:external=True
neutron subnet-create --ip_version 4 --gateway $PUBLIC_GATEWAY public $PUBLIC_RANGE --allocation-pool start=$PUBLIC_START,end=$PUBLIC_END --disable-dhcp --name public-subnet
neutron router-gateway-set ${TENANT_ROUTER_NAME} public
查看br-ex
ip -o link show br-ex
59: br-ex: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default
link/ether a0:48:1c:ab:df:b5 brd ff:ff:ff:ff:ff:ff
列出所有的网卡
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 ip -o -d link list
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 promiscuity 0
241: qr-29003a09-e7: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default
link/ether fa:16:3e:84:6e:cc brd ff:ff:ff:ff:ff:ff promiscuity 1
查看qg网卡
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 ip -o link show qg-556ca938-e1
但是网卡不存在
Device "qg-556ca938-e1" does not exist.
查看br-ex
ip -o link show br-ex
创建新的网卡qg，attach到br-ex
ovs-vsctl -- --if-exists del-port qg-556ca938-e1 -- add-port br-ex qg-556ca938-e1 -- set Interface qg-556ca938-e1 type=internal -- set Interface qg-556ca938-e1 external-ids:iface-id=556ca938-e11b-4246-bdc1-ef25c91b7593 -- set Interface qg-556ca938-e1 external-ids:iface-status=active -- set Interface qg-556ca938-e1 external-ids:attached-mac=fa:16:3e:68:12:c0
设置网卡mac
ip link set qg-556ca938-e1 address fa:16:3e:68:12:c0
查看所有的namespace
ip -o netns list
qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82
qdhcp-66b9930b-2871-414c-8c6f-991a6a8cffe0
qrouter-26a45e0e-a58a-443b-a972-d62c0c5a1323
qdhcp-760d2c5e-4938-49b0-bffe-c77c5b141d18
将qg网卡设置到namespace中
ip link set qg-556ca938-e1 netns qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82
将网卡设置为up
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 ip link set qg-556ca938-e1 up
查看网卡地址
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 ip addr show qg-556ca938-e1 permanent scope global
设置网卡地址
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 ip -4 addr add 16.158.165.105/22 brd 16.158.167.255 scope global dev qg
-556ca938-e1
添加router表
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 route add default gw 16.158.164.1
设置iptables
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 iptables-save –c
# Generated by iptables-save v1.4.21 on Thu Jul 17 01:58:30 2014
*nat
:PREROUTING ACCEPT [4:425]
:INPUT ACCEPT [1:229]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
:neutron-l3-agent-OUTPUT - [0:0]
:neutron-l3-agent-POSTROUTING - [0:0]
:neutron-l3-agent-PREROUTING - [0:0]
:neutron-l3-agent-float-snat - [0:0]
:neutron-l3-agent-snat - [0:0]
:neutron-postrouting-bottom - [0:0]
[4:425] -A PREROUTING -j neutron-l3-agent-PREROUTING
[0:0] -A OUTPUT -j neutron-l3-agent-OUTPUT
[0:0] -A POSTROUTING -j neutron-l3-agent-POSTROUTING
[0:0] -A POSTROUTING -j neutron-postrouting-bottom
[0:0] -A neutron-l3-agent-PREROUTING -d 169.254.169.254/32 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 9697
[0:0] -A neutron-l3-agent-snat -jneutron-l3-agent-float-snat
[0:0] -A neutron-postrouting-bottom -j neutron-l3-agent-snat
COMMIT
# Completed on Thu Jul 17 01:58:30 2014
# Generated by iptables-save v1.4.21 on Thu Jul 17 01:58:30 2014
*mangle
:PREROUTING ACCEPT [4:425]
:INPUT ACCEPT [1:229]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
COMMIT
# Completed on Thu Jul 17 01:58:30 2014
# Generated by iptables-save v1.4.21 on Thu Jul 17 01:58:30 2014
*filter
:INPUT ACCEPT [1:229]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:neutron-filter-top - [0:0]
:neutron-l3-agent-FORWARD - [0:0]
:neutron-l3-agent-INPUT - [0:0]
:neutron-l3-agent-OUTPUT - [0:0]
:neutron-l3-agent-local - [0:0]
[1:229] -A INPUT -j neutron-l3-agent-INPUT
[0:0] -A FORWARD -j neutron-filter-top
[0:0] -A FORWARD -j neutron-l3-agent-FORWARD
[0:0] -A OUTPUT -j neutron-filter-top
[0:0] -A OUTPUT -j neutron-l3-agent-OUTPUT
[0:0] -A neutron-filter-top -j neutron-l3-agent-local
[0:0] -A neutron-l3-agent-INPUT -d 127.0.0.1/32 -p tcp -m tcp --dport 9697 -j ACCEPT
COMMIT
# Completed on Thu Jul 17 01:58:30 2014
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 iptables-restore –c
显示网卡信息
ip netns exec qrouter-d62d417d-2005-46d7-a83b-b1e5c0a36d82 ip addr show qg-556ca938-e1
242: qg-556ca938-e1: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default
link/ether fa:16:3e:68:12:c0 brd ff:ff:ff:ff:ff:ff
inet 16.158.165.105/22 brd 16.158.167.255 scope global qg-556ca938-e1
valid_lft forever preferred_lft forever
inet6 fe80::f816:3eff:fe68:12c0/64 scope link tentative
valid_lft forever preferred_lft forever
转自http://www.cnblogs.com/popsuper1982/p/3849822.html
neutron创建network执行的那些命令的更多相关文章
- 使用jar命令打jar/war包、创建可执行jar包、运行jar包、及批处理脚本编写
jar 命令 jar 是一个jar.exe可执行命令,即可以生成jar文件,也可以生成war文件 使用示例:jar -cvf ../xxx.jar * -c create,创建新的归档文档 ...
- Neutron 理解 (1): Neutron 所实现的网络虚拟化 [How Neutron Virtualizes Network]
学习 Neutron 系列文章: (1)Neutron 所实现的网络虚拟化 (2)Neutron OpenvSwitch + VLAN 虚拟网络 (3)Neutron OpenvSwitch + GR ...
- BSA Network Shell系列-nexec命令
# nexec ## 1 说明:nexec是远程命令接口引擎 ,用于在远程主机执行命令 nexec [-?] [-t term] [-o] [-i] [-l] [-nohup hostname &qu ...
- Neutron vxlan network
OpenStack 还支持 vxlan 和 gre 这两种 overlay network. overlay network 是指建立在其他网络上的网络. 该网络中的节点可以看作通过虚拟(或逻辑) ...
- Neutron Vlan Network 学习
vlan network 是带 tag 的网络,是实际应用最广泛的网络类型. 下图是 vlan100 网络的示例. 1. 三个 instance 通过 TAP 设备连接到名为 brqXXXX ...
- Neutron flat network 学习
flat network 是不带 tag 的网络,要求宿主机的物理网卡直接与 linux bridge 连接,这意味着: 每个 flat network 都会独占一个物理网卡. 在 ML2 配置中 ...
- 创建maven项目（cmd 命令）
2016五月 22 原 创建maven项目(cmd 命令) 分类:maven (994) (0) 1.普通方式创建 1)进入cmd窗口执行 mvn archetype:generate 2) 光标停止 ...
- (八)Eclipse创建Maven项目运行mvn命令
1.Eclipse创建Maven项目 使用Eclipse创建一个Maven项目非常的简单,选择菜单项File>New>Other(也可以在项目结构空白处右击鼠标键),在弹出的对话框中选择M ...
- Neutron Vlan Network 原理- 每天5分钟玩转 OpenStack（92）
前面我们陆续学习了 Neutron local network,flat network 和 DHCP 服务,从本节将开始讨论 vlan network. vlan network 是带 tag 的网 ...
随机推荐
- /etc/rc.d/与/etc/rc.d/init.d的关系
/etc/init.d指向/etc/rc.d/init.d目录 . 除了直接调用脚本外(如/etc/rc.d/init.d/xinetd),还可以用service命令来控制init.d目录下的服务如 ...
- MVP -----个人理解与示例（android例子 实现）
MVP 也就是Model View Presenter模式,是建立一个工程的一种模式. ======================================================== ...
- sanBox部署简介
参考资料:1 http://www.kaaproject.org/getting-started/ 此链接告诉我们部署sandbox的两种方法. 2 http://docs.kaaprojec ...
- 51nod 1183 编辑距离(dp)
题目链接:51nod 1183 编辑距离 #include<cstdio> #include<cstring> #include<algorithm> using ...
- winform界面闪退
我在登录成功后跳转到主页面的时候,总是会闪退,调试发现调用这个ShowDialog之后,就会触发主页面的FormClosing C# 窗体关闭时可以触发的事件 FormClosing :在窗体关闭时, ...
- 递归算法（三）——不借助四则运算实现加法
问题 求两个整型变量的和,不能使用四则运算,但可以使用位运算. 思路 以二进制形式,考虑两个整数相加: a = 01101001b b = 11100111b s = ???????? 一个常见的结 ...
- 简单json语句转化为map保存
主要用到了 net.sf.json.JSONObject类 需要用到的jar包 : jar包下载地址 package test; import java.io.BufferedReader; impo ...
- Android MediaRecorder录制音频
今天介绍一下在Android中怎么录制音频,在Android中使用MediaRecorder来录制音频,步骤: 1.创建MediaRecorder对象. 2.调用MediaRecorder对象的set ...
- Objective-C学习笔记－第一天(3)
话不多说,学了这么多,写个快速排序先. 除了快排,以后有时间还要加堆排.归并等等. 今天学了有,类.协议.语法. 因为算法类,不止一个算法.所以新建一个Algorithm(算法)协议: #import ...
- 将事件绑定在html标签中和js动态绑定的区别
一:绑定在标签中: 能够一眼看出那些元素绑定了什么事件. 只能将元素和事件逐一实现绑定. 二js动态绑定: 可以一次动态的给多个元素绑定事件,批量绑定事件. html标签绑定的缺点: ①:可能有时间差 ...