實戰hadoop2.6.3+zookeeper3.4.6+hbase1.0.2高可用叢集方案
一、安裝前準備
1.環境5台
<a href="http://s4.51cto.com/wyfs02/M00/85/8A/wKioL1eoFfKBytUEAABpzvGSCME119.png-wh_500x0-wm_3-wmp_4-s_970805712.png" target="_blank"></a>
2、修改hosts檔案
[root@hadoop01 ~]# cat /etc/hosts
192.168.10.201hadoop01
192.168.10.202hadoop02
192.168.10.203hadoop03
192.168.10.204hadoop04
192.168.10.205hadoop05
3、ssh 免密碼登入
在每台操作
[root@hadoop01 ~]# mkidr ~/.ssh
[root@hadoop01 ~]# chmod 700 ~/.ssh
[root@hadoop01 ~]#cd ~/.ssh/
[root@hadoop01 .ssh ]ssh-keygen -t rsa
五台操作完成 後做成公鑰檔案
[root@hadoop01 .ssh ] ssh hadoop02 cat /root/.ssh/id_rsa.pub >> authorized_keys
[root@hadoop01 .ssh ] ssh hadoop03 cat /root/.ssh/id_rsa.pub >> authorized_keys
[root@hadoop01 .ssh ] ssh hadoop04 cat /root/.ssh/id_rsa.pub >> authorized_keys
[root@hadoop01 .ssh ] ssh hadoop05 cat /root/.ssh/id_rsa.pub >> authorized_keys
[root@hadoop01 .ssh ] ssh hadoop01 cat /root/.ssh/id_rsa.pub >> authorized_keys
[root@hadoop01 .ssh]# chmod 600 authorized_keys
[root@hadoop01 .ssh]# scp authorized_keys hadoop02:/root/.ssh/
[root@hadoop01 .ssh]# scp authorized_keys hadoop03:/root/.ssh/
[root@hadoop01 .ssh]# scp authorized_keys hadoop04:/root/.ssh/
[root@hadoop01 .ssh]# scp authorized_keys hadoop05:/root/.ssh/
測試ssh信任
[root@hadoop01 .ssh]# ssh hadoop02 date
Mon Aug 8 11:07:23 CST 2016
[root@hadoop01 .ssh]# ssh hadoop03 date
Mon Aug 8 11:07:26 CST 2016
[root@hadoop01 .ssh]# ssh hadoop04 date
Mon Aug 8 11:07:29 CST 2016
[root@hadoop01 .ssh]# ssh hadoop05 date
5.服務時間同步(五台操作)
yum -y install ntpdate
[root@hadoop01 .ssh]# crontab -l
0 * * * * /usr/sbin/ntpdate 0.rhel.pool.ntp.org && /sbin/clock -w
可以采用别的方案同步時間
6.修改檔案打開數（五台操作）
[root@hadoop01 ~]# vi /etc/security/limits.conf
root soft nofile 65535
root hard nofile 65535
root soft nproc 32000
root hard nproc 32000
[root@hadoop01 ~]# vi /etc/pam.d/login
session required pam_limits.so
修改完後重新開機系統
二、安裝hadoop+zookeeper HA
1.安裝jdk (五台操作)
解壓jdk
[root@hadoop01 ~] cd /opt
[root@hadoop01 opt]# tar zxvf jdk-7u21-linux-x64.tar.gz
[root@hadoop01 opt]# mv jdk1.7.0_21 jdk
配置到環境變量/etc/profile
[root@hadoop01 opt]# vi /etc/profile
#java
JAVA_HOME=/opt/jdk
PATH=$JAVA_HOME/bin:$PATH
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export JAVA_HOME
export PATH
export CLASSPATH
配置檔案生效
[root@hadoop01 opt]# source /etc/profile
[root@hadoop01 opt]# java -version
java version "1.7.0_21"
Java(TM) SE Runtime Environment (build 1.7.0_21-b11)
Java HotSpot(TM) 64-Bit Server VM (build 23.21-b01, mixed mode)
以上說明生效
2.解壓hadoop并修改環境變量
[root@hadoop01 ~]# tar zxvf hadoop-2.6.3.tar.gz
[root@hadoop01 ~]#mkdir /data
[root@hadoop01 ~]# mv hadoop-2.6.3 /data/hadoop
[root@hadoop01 data]# vi /etc/profile
##hadoop
export HADOOP_HOME=/data/hadoop
export PATH=$PATH:$HADOOP_HOME/bin:$HADOOP_HOME/bin
[root@hadoop01 data]# source /etc/profile
3.修改hadoop配置檔案
[root@hadoop01 data]# cd /data/hadoop/etc/hadoop/
[root@hadoop01 hadoop]# vi slaves
hadoop01
hadoop02
hadoop03
hadoop04
hadoop05
以上利用hadoop01,hadoop02兩台磁盤空間，也增加進去了，不介意增加。
[root@hadoop01 hadoop]# vi hadoop-env.sh
<a href="http://s2.51cto.com/wyfs02/M01/85/8A/wKiom1eoFqOBSHdOAAA2BFMOv5w357.png-wh_500x0-wm_3-wmp_4-s_4223428174.png" target="_blank"></a>
[root@hadoop01 hadoop]# vi yarn-env.sh
修改core-site.xml檔案
[root@hadoop01 hadoop]# vi core-site.xml
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. See accompanying LICENSE file.
-->
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>fs.defaultFS</name>
<value>hdfs://cluster</value>
<description>The name of the default file system.</description>
<final>true</final>
</property>
<name>hadoop.tmp.dir</name>
<value>/data/hadoop/tmp</value>
<name>ha.zookeeper.quorum</name>
<value>hadoop01:2190,hadoop02:2190,hadoop03:2190,hadoop04:2190,hadoop05:2190</value>
<name>io.file.buffer.size</name>
<value>2048</value>
<property>
<name>dfs.ha.fencing.methods</name>
<value>sshfence</value>
</property>
<property>
<name>dfs.ha.fencing.ssh.private-key-files</name>
<value>/root/.ssh/id_dsa</value>
</configuration>
修改hdfs-site.xml檔案
[root@hadoop01 hadoop]# vi hdfs-site.xml
<name>dfs.nameservices</name>
<value>cluster</value>
<name>dfs.ha.namenodes.cluster</name>
<value>nn1,nn2</value>
<name>dfs.namenode.rpc-address.cluster.nn1</name>
<value>hadoop01:8020</value>
<name>dfs.namenode.rpc-address.cluster.nn2</name>
<value>hadoop02:8020</value>
<name>dfs.namenode.http-address.cluster.nn1</name>
<value>hadoop01:50070</value>
<name>dfs.namenode.http-address.cluster.nn2</name>
<value>hadoop02:50070</value>
<name>dfs.namenode.servicerpc-address.cluster.nn1</name>
<value>hadoop01:53333</value>
</property>
<property>
<name>dfs.namenode.servicerpc-address.cluster.nn2</name>
<value>hadoop02:53333</value>
<name>dfs.namenode.shared.edits.dir</name>
<value>qjournal://hadoop01:8485;hadoop02:8485;hadoop03:8485;hadoop04:8485;hadoop05:8485/cluster</value>
<name>dfs.client.failover.proxy.provider.cluster</name>
<value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>
<name>dfs.journalnode.edits.dir</name>
<value>/data/hadoop/mydata/journal</value>
<name>dfs.replication</name>
<value>3</value>
<property>
<name>dfs.namenode.name.dir</name>
<value>file:/data/hadoop/mydata/name</value>
</property>
<name>dfs.datanode.data.dir</name>
<value>file:/data/hadoop/mydata/data</value>
<name>dfs.ha.automatic-failover.enabled</name>
<value>true</value>
<name>dfs.webhdfs.enabled</name>
<name>dfs.journalnode.http-address</name>
<value>0.0.0.0:8480</value>
<name>dfs.journalnode.rpc-address</name>
<value>0.0.0.0:8485</value>
<property>
<name>dfs.permissions</name>
<value>false</value>
修改mapred-site.xml
[root@hadoop01 hadoop]# vi mapred-site.xml
<?xml version="1.0"?>
<name>mapreduce.framework.name</name>
<value>yarn</value>
<name>mapreduce.cluster.temp.dir</name>
<value>/data/hadoop/mydata/mr_temp</value>
<name>mareduce.jobhistory.address</name>
<value>hadoop01:10020</value>
<name>mapreduce.jobhistory.webapp.address</name>
<value>hadoop01:19888</value>
修改yarn-site.xml檔案
[root@hadoop01 hadoop]# vi yarn-site.xml
<!-- Site specific YARN configuration properties -->
<name>yarn.resourcemanager.connect.retry-interval.ms</name>
<value>60000</value>
<name>yarn.resourcemanager.ha.enabled</name>
<name>yarn.resourcemanager.cluster-id</name>
<value>rm-cluster</value>
<name>yarn.resourcemanager.ha.rm-ids</name>
<value>rm1,rm2</value>
<name>yarn.resourcemanager.ha.id</name>
<value>rm1</value>
<name>yarn.resourcemanager.hostname.rm1</name>
<value>hadoop01</value>
<name>yarn.resourcemanager.hostname.rm2</name>
<value>hadoop02</value>
<name>yarn.resourcemanager.recovery.enabled</name>
<name>yarn.resourcemanager.store.class</name>
<value>org.apache.hadoop.yarn.server.resourcemanager.recovery.ZKRMStateStore</value>
<name>yarn.resourcemanager.zk-address</name>
<value>hadoop01:2190,hadoop02:2190,hadoop03:2190,hadoop04:2190,hadoop05:2190,</value>
<name>yarn.resourcemanager.address.rm1</name>
<value>${yarn.resourcemanager.hostname.rm1}:23140</value>
<name>yarn.resourcemanager.scheduler.address.rm1</name>
<value>${yarn.resourcemanager.hostname.rm1}:23130</value>
<name>yarn.resourcemanager.webapp.https.address.rm1</name>
<value>${yarn.resourcemanager.hostname.rm1}:23189</value>
<name>yarn.resourcemanager.webapp.address.rm1</name>
<value>${yarn.resourcemanager.hostname.rm1}:23188</value>
<name>yarn.resourcemanager.resource-tracker.address.rm1</name>
<value>${yarn.resourcemanager.hostname.rm1}:23125</value>
<name>yarn.resourcemanager.admin.address.rm1</name>
<value>${yarn.resourcemanager.hostname.rm1}:23141</value>
<name>yarn.resourcemanager.address.rm2</name>
<value>${yarn.resourcemanager.hostname.rm2}:23140</value>
<name>yarn.resourcemanager.scheduler.address.rm2</name>
<value>${yarn.resourcemanager.hostname.rm2}:23130</value>
<name>yarn.resourcemanager.webapp.https.address.rm2</name>
<value>${yarn.resourcemanager.hostname.rm2}:23189</value>
<name>yarn.resourcemanager.webapp.address.rm2</name>
<value>${yarn.resourcemanager.hostname.rm2}:23188</value>
<name>yarn.resourcemanager.resource-tracker.address.rm2</name>
<value>${yarn.resourcemanager.hostname.rm2}:23125</value>
<name>yarn.resourcemanager.admin.address.rm2</name>
<value>${yarn.resourcemanager.hostname.rm2}:23141</value>
<name>yarn.resourcemanager.scheduler.class</name>
<value>org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler</value>
<name>yarn.scheduler.fair.allocation.file</name>
<value>${yarn.home.dir}/etc/hadoop/fairscheduler.xml</value>
<name>yarn.nodemanager.local-dirs</name>
<value>/data/hadoop/mydata/yarn_local</value>
<name>yarn.nodemanager.log-dirs</name>
<value>/data/hadoop/mydata/yarn_log</value>
<name>yarn.nodemanager.remote-app-log-dir</name>
<value>/data/hadoop/mydata/yarn_remotelog</value>
<name>yarn.app.mapreduce.am.staging-dir</name>
<value>/data/hadoop/mydata/yarn_userstag</value>
<name>mapreduce.jobhistory.intermediate-done-dir</name>
<value>/data/hadoop/mydata/yarn_intermediatedone</value>
<name>mapreduce.jobhistory.done-dir</name>
<value>/data/hadoop/mydata/yarn_done</value>
</property>
<name>yarn.log-aggregation-enable</name>
<value>true</value>
<name>yarn.nodemanager.resource.memory-mb</name>
<value>2048</value>
<name>yarn.nodemanager.vmem-pmem-ratio</name>
<value>4.2</value>
<name>yarn.nodemanager.resource.cpu-vcores</name>
<value>2</value>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
<name>yarn.nodemanager.aux-services.mapreduce.shuffle.class</name>
<value>org.apache.hadoop.mapred.ShuffleHandler</value>
<description>Classpath for typical applications.</description>
<name>yarn.application.classpath</name>
<value>
$HADOOP_HOME/etc/hadoop,
$HADOOP_HOME/share/hadoop/common/*,
$HADOOP_HOME/share/hadoop/common/lib/*,
$HADOOP_HOME/share/hadoop/hdfs/*,
$HADOOP_HOME/share/hadoop/hdfs/lib/*,
$HADOOP_HOME/share/hadoop/mapreduce/*,
$HADOOP_HOME/share/hadoop/mapreduce/lib/*,
$HADOOP_HOME/share/hadoop/yarn/*,
$HADOOP_HOME/share/hadoop/yarn/lib/*
</value>
修改fairscheduler.xml檔案
[root@hadoop01 hadoop]# vi fairscheduler.xml
<allocations>
<queue name="news">
<minResources>1024 mb, 1 vcores </minResources>
<maxResources>1536 mb, 1 vcores </maxResources>
<maxRunningApps>5</maxRunningApps>
<minSharePreemptionTimeout>300</minSharePreemptionTimeout>
<weight>1.0</weight>
<aclSubmitApps>root,yarn,search,hdfs</aclSubmitApps>
</queue>
<queue name="crawler">
<minResources>1024 mb, 1 vcores</minResources>
<maxResources>1536 mb, 1 vcores</maxResources>
<queue name="map">
</allocations>
建立相關xml配置中目錄
mkdir -p /data/hadoop/mydata/yarn
4.解壓zookeeper并修改環境變量
[root@hadoop01 ~]# tar zxvf zookeeper-3.4.6.tar.gz
[root@hadoop01 ~]#mv zookeeper-3.4.6 /data/zookeeper
[root@hadoop01 ~]# vi /etc/profile
##zookeeper
export ZOOKEEPER_HOME=/data/zookeeper
export PATH=$PATH:$ZOOKEEPER_HOME/bin:$ZOOKEEPER_HOME/conf
[root@hadoop01 ~]# source /etc/profile
5.修改zookeeper配置檔案
[root@hadoop01 ~]# cd /data/zookeeper/conf/
[root@hadoop01 conf]# cp zoo_sample.cfg zoo.cfg
[root@hadoop01 conf]# vi zoo.cfg
# The number of milliseconds of each tick
tickTime=2000
# The number of ticks that the initial
# synchronization phase can take
initLimit=10
# The number of ticks that can pass between
# sending a request and getting an acknowledgement
syncLimit=5
# the directory where the snapshot is stored.
# do not use /tmp for storage, /tmp here is just
# example sakes.
dataDir=/data/hadoop/mydata/zookeeper
dataLogDir=/data/hadoop/mydata/zookeeperlog
# the port at which the clients will connect
clientPort=2190
server.1=hadoop01:2888:3888
server.2=hadoop02:2888:3888
server.3=hadoop03:2888:3888
server.4=hadoop04:2888:3888
server.5=hadoop05:2888:3888
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
#
# Be sure to read the maintenance section of the
# administrator guide before turning on autopurge.
# http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
# The number of snapshots to retain in dataDir
#autopurge.snapRetainCount=3
# Purge task interval in hours
# Set to "0" to disable auto purge feature
#autopurge.purgeInterval=1
建立目錄
mkdir /data/hadoop/mydata/zookeeper
mkdir /data/hadoop/mydata/zookeeperlog
6.把配置hadoop、zookeeper檔案目錄到其他四台中
[root@hadoop01 ~]# scp -r /data/hadoop hadoop02:/data/
[root@hadoop01 ~]# scp -r /data/hadoop hadoop03:/data/
[root@hadoop01 ~]# scp -r /data/hadoop hadoop04:/data/
[root@hadoop01 ~]# scp -r /data/hadoop hadoop05:/data/
[root@hadoop01 ~]# scp -r /data/zookeeper hadoop02:/data/
[root@hadoop01 ~]# scp -r /data/zookeeper hadoop03:/data/
[root@hadoop01 ~]# scp -r /data/zookeeper hadoop04:/data/
[root@hadoop01 ~]# scp -r /data/zookeeper hadoop05:/data/
在hadoop02修改yarn-site.xml
[root@hadoop02 hadoop]# cd /data/hadoop/etc/hadoop/
把rm1修改成rm2
[root@hadoop02 hadoop]# vi yarn-site.xml
<value>rm2</value>
[root@hadoop01 ~]# vi /data/hadoop/mydata/zookeeper/myid
1
[root@hadoop02 ~]# vi /data/hadoop/mydata/zookeeper/myid
2
[root@hadoop03 ~]# vi /data/hadoop/mydata/zookeeper/myid
3
[root@hadoop04 ~]# vi /data/hadoop/mydata/zookeeper/myid
4
[root@hadoop05 ~]# vi /data/hadoop/mydata/zookeeper/myid
5
7、啟動zookeeper
五台操作zkServer.sh start
[root@hadoop01 ~]# zkServer.sh start
[root@hadoop01 ~]# zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /data/zookeeper/bin/../conf/zoo.cfg
Mode: follower
[root@hadoop03 ~]# zkServer.sh status
Mode: leader
You have new mail in /var/spool/mail/root
正常情況隻有一台leader狀态
8、格式化zookeeper叢集
在hadoop機器執行指令
[root@hadoop01 ~]# hdfs zkfc -formatZK
9.啟動journalnode程序
在每台啟動（五台）
[root@hadoop01 ~]# cd /data/hadoop/sbin/
[root@hadoop01 sbin]# ./hadoop-daemon.sh start journalnode
10.格式化namenode
在hadoop01上執行指令
[root@hadoop01 ~]# hdfs namenode -format
11.啟動namenode
在hadoop01執行指令
[root@hadoop01 sbin]# ./hadoop-daemon.sh start namenode
12.将剛才格式化的namenode資訊同步麼備用namenode上
[root@hadoop01 ~]# hdfs namenode -bootstrapStandby
13.在hadoop02上啟動namenode
[root@hadoop02 ~]# cd /data/hadoop/sbin/
[root@hadoop02 sbin]# ./hadoop-daemon.sh start namenode
14.啟動所有datanode
在每台執行這是根據slaves來的
[root@hadoop01 sbin]# ./hadoop-daemon.sh start datanode
15.啟動yarn
root@hadoop01 ~]# cd /data/hadoop/sbin/
[root@hadoop01 sbin]# ./start-yarn.sh
16.啟動ZKFC
在hadoop01和hadoop02上啟動
[root@hadoop01 sbin]# ./hadoop-daemon.sh start zkfc
17.啟動成功結果
<a href="http://s1.51cto.com/wyfs02/M02/85/8A/wKioL1eoGDLDu0HfAAHAGNBDhVs350.png-wh_500x0-wm_3-wmp_4-s_3000818196.png" target="_blank"></a>
<a href="http://s3.51cto.com/wyfs02/M00/85/8A/wKiom1eoGD6xchrGAAHnuOGZ_jI101.png-wh_500x0-wm_3-wmp_4-s_1001019603.png" target="_blank"></a>
三、安裝hbase HA
1.解壓hbase修改配置檔案
[root@hadoop01 ~]# tar zxvf hbase-1.0.2-bin.tar.gz
[root@hadoop01 ~]# mv hbase-1.0.2 /data/hbase
配置環境變量
##hbase
export HBASE_HOME=/data/hbase
export PATH=$PATH:$HBASE_HOME/bin
[root@hadoop01 ~]# cd /data/hbase/conf/
[root@hadoop01 conf]# vi hbase-env.sh
# The java implementation to use. Java 1.7+ required.
export JAVA_HOME="/opt/jdk"
# Extra Java CLASSPATH elements. Optional.
#記得以下一定要配置,HMaster會啟動不了
export HBASE_CLASSPATH=/data/hadoop/etc/hadoop
# Where log files are stored. $HBASE_HOME/logs by default.
export HBASE_LOG_DIR=/data/hbase/logs
# Tell HBase whether it should manage it's own instance of Zookeeper or not.
export HBASE_MANAGES_ZK=false
修改hbase-site.xml
[root@hadoop01 conf]# vi hbase-site.xml
/**
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
<property>
<name>hbase.rootdir</name>
<value>hdfs://cluster/hbase</value>
</property>
<name>hbase.cluster.distributed</name>
<value>true</value>
<name>hbase.tmp.dir</name>
<value>/data/hbase/tmp</value>
</property>
<property>
<name>hbase.master.port</name>
<value>60000</value>
<name>hbase.zookeeper.property.dataDir</name>
<value>/data/hadoop/mydata/zookeeper</value>
<name>hbase.zookeeper.quorum</name>
<value>hadoop01,hadoop02,hadoop03,hadoop04,hadoop05</value>
</property>
<name>hbase.zookeeper.property.clientPort</name>
<value>2190</value>
<property>
<name>zookeeper.session.timeout</name>
<value>120000</value>
</property>
<property>
<name>hbase.regionserver.restart.on.zk.expire</name>
[root@hadoop01 conf]# vi regionservers
~
建立檔案目錄
mkdir /data/hbase/tmp
增加backup-master
[root@hadoop01 conf]# vi backup-masters
以上都配置完成
2、把檔案傳到其他伺服器上
[root@hadoop01 conf]# scp -r /data/hbase hadoop02:/data/
[root@hadoop01 conf]# scp -r /data/hbase hadoop03:/data/
[root@hadoop01 conf]# scp -r /data/hbase hadoop04:/data/
[root@hadoop01 conf]# scp -r /data/hbase hadoop05:/data/
3.啟動hbase
[root@hadoop01 conf]# start-hbase.sh
4.啟動結果
可以通過jps檢視
[root@hadoop01 conf]# jps
2540 NodeManager
1686 QuorumPeerMain
2134 JournalNode
2342 DFSZKFailoverController
3041 HMaster
1933 DataNode
3189 HRegionServer
2438 ResourceManager
7848 Jps
1827 NameNode
以後啟動過程
每台執行（五台）
在hadoop01啟動
[root@hadoop01 sbin]# ./start-dfs.sh
最後啟動hbase
[root@hadoop01 sbin]# start-hbase.sh
關閉過程
先關閉hbase
stop-hbase.sh
在hadoop01關閉
[root@hadoop01 sbin]# ./stop-yarn.sh
[root@hadoop01 sbin]# ./stop-dfs.sh
<a href="http://down.51cto.com/data/2368030" target="_blank">附件：http://down.51cto.com/data/2368030</a>
版權聲明：原創作品，如需轉載，請注明出處。否則将追究法律責任
本文轉自 jxzhfei 51CTO部落格，原文連結:http://blog.51cto.com/jxzhfei/1835598
![Java String.format方法的簡單使用[圖]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)