1.在使用mybatis的动态sql时，有时候遇到根据条件判断添加where后面的筛选条件的情况，会出现多余的AND或者OR：2.使用where关键字:2.1当第一个参数为空时,拼接后的sql为:select*fromtdwhereandphone=.......;2.2当所有的参数都为空时,拼接后的sql为:select*fromtdwhere.....,显然这样的sql不是完整的sql,执行时会报错.3.使用where标签时:3.1当第一个参数为空时,拼接后的sql为:select*fromtdwherephone=......(若语句的开头为AND或者OR时,where元素会将他们去除).3.2当所有的参数都为空时,拼接后的sql为:select*fromtd.(where元素只会在至少有一个子元素的条件返回SQL子句的情况下才去插入“WHERE”子句)。
下载与ES对应的版本：官网地址解压修改$KIBANA_HOME/config/kibana.yml文件启动Kibana：sudo$KIBANA_HOME/bin/kibana浏览器输入host:5601能正常打开页面即可KAAE插件安装KAAE为Kibana的插件，主要用来监控和报警，用户可以根据需求配置相应的监控条件，达到某个条件会发出报警消息，同时KAAE也提供有报告Report功能，能够将查询到的结果生成图表发送到指定邮箱。安装：$KIBANA_HOME/bin/kibana-pulgininstallhttps://github.com/sirensolutions/sentinl/releases/download/tag-6.2.3-3/sentinl-v6.2.4.zip配置kibana.yml文件，在最后加上：重启Kibana后，浏览器输入：http://ip:5601出现以下界面说明插件安装成功可以在页面上按照需求配置监听报警
Vue+SpringBoot实现WebSocket通信服务端在SpringBoot项目中添加ServerEndpointExporterBean的方法@BeanpublicServerEndpointExporterexporter(){returnnewServerEndpointExporter();}创建WebSocket客户端管理类:WebSocketComponent.javapackagecn.coralcloud.blog.web.component;importcom.alibaba.fastjson.JSON;importorg.springframework.stereotype.Component;importjavax.websocket.*;importjavax.websocket.server.ServerEndpoint;importjava.io.IOException;importjava.util.Objects;importjava.util.concurrent.CopyOnWriteArraySet;/**@authorgeff@nameWebSocketComponent@description@date2019-12-1814:22/@ServerEndpoint(value="/websocket")@ComponentpublicclassWebSocketComponent{/**静态变量，用来记录当前在线连接数。应该把它设计成线程安全的。/privatestaticintonlineCount=0;/**concurrent包的线程安全Set，用来存放每个客户端对应的CumWebSocket对象。/privatestaticCopyOnWriteArraySetwebSocketSet=newCopyOnWriteArraySet<>();/**与某个客户端的连接会话，需要通过它来给客户端发送数据/privateSessionsession;/**连接建立成功调用的方法@paramsessionsession/@OnOpenpublicvoidonOpen(Sessionsession){this.session=session;//加入set中webSocketSet.add(this);//添加在线人数addOnlineCount();System.out.println("新连接接入。当前在线人数为："+getOnlineCount());}/**连接关闭调用的方法/@OnClosepublicvoidonClose(){//从set中删除webSocketSet.remove(this);//在线数减1subOnlineCount();System.out.println("有连接关闭。当前在线人数为："+getOnlineCount());}/**收到客户端消息后调用@parammessagemessage@paramsessionsession/@OnMessagepublicvoidonMessage(Stringmessage,Sessionsession){System.out.println("客户端发送的消息："+message);sendAll(JSON.toJSONString(messageDTO),session.getId());}/**群发@parammessagemessage/privatestaticvoidsendAll(Stringmessage,StringsessionId){webSocketSet.forEach(item->{if(!item.session.getId().equals(sessionId)){//群发try{item.sendMessage(message);}catch(IOExceptione){e.printStackTrace();}}});}/**发生错误时调用@paramsessionsession@paramerrorerror/@OnErrorpublicvoidonError(Sessionsession,Throwableerror){System.out.println("----websocket-------有异常啦");error.printStackTrace();}/**减少在线人数/privatevoidsubOnlineCount(){WebSocketComponent.onlineCount--;}/**添加在线人数/privatevoidaddOnlineCount(){WebSocketComponent.onlineCount++;}/**当前在线人数@returnint/publicstaticsynchronizedintgetOnlineCount(){returnonlineCount;}/**发送信息@parammessagemessagethrowsIOException/publicvoidsendMessage(Stringmessage)throwsIOException{//获取session远程基本连接发送文本消息this.session.getBasicRemote().sendText(message);//this.session.getAsyncRemote().sendText(message);}@Overridepublicbooleanequals(Objecto){if(this==o){returntrue;}if(o==null||getClass()!=o.getClass()){returnfalse;}WebSocketComponentthat=(WebSocketComponent)o;returnObjects.equals(session,that.session);}@OverridepublicinthashCode(){returnObjects.hash(session);}}@ServerEndpoint注解标识当前WebSocket服务端endpoint地址,本文实际前端访问的ws地址为:ws://localhost:8080/websocket。至此，服务端工作完成。页面VUE端<template><el-cardv-loading="loading"element-loading-spinner="el-icon-loading":body-style="{padding:'5px',backgroundColor:'#eee'}"class="socket-box"shadow="hover"><divclass="socket-box__content":style="{height:(boxHeight-125)+'px'}"id="socket-content"><divv-if="hasMore"@click="loadMore"class="load-more"><span>加载更多</span></div><divv-elsestyle="width:100%;text-align:center;font-size:12px">没有更多了</div><divclass="item"v-for="minmessages":class="checkMe(m)?'sender':''"><divclass="slide"><divclass="avatar":style="{background:m.background}">{{m.name.substring(0,1)}}</div><divclass="meta"><divclass="name">{{m.name}}</div><divclass="date">{{m.createTime|datetime}}</div></div></div><p>{{m.content}}</p></div></div><divclass="socket-box__footer"><el-form@submit.native.prevent><el-form-item><el-inputtype="textarea"resize="none":rows="3":disabled="!connect":placeholder="connect?'输入内容...':'当前连接断开,请刷新重试!'":clearable="true"v-model="message"@keydown.native.enter="submitMsgForm"></el-input></el-form-item><el-form-item><el-button@click="sendMsg(message)":disabled="!connect"style="width:100%"type="primary"size="small">发送(Enter)</el-button></el-form-item></el-form></div></el-card></template><script>import{GET}from"@/api";exportdefault{name:"Chatroom",data(){return{messages:[],message:'',//boxHeight:document.documentElement.clientHeight-85,hasMore:true,pager:{pageNo:1,pageSize:10,total:0},loading:false,connect:false}},props:{boxHeight:{type:Number,required:true}},methods:{submitMsgForm(event){if(event.shiftKey){return;}event.preventDefault();this.sendMsg(this.message)},checkMe(message){letuser=localStorage.getItem("socketUser");if(user){user=JSON.parse(user);returnuser.uid===message.uid}else{returnfalse;}},initWebSocket:function(){this.websock=newWebSocket(`ws://localhost:8080/websocket`);this.websock.onopen=this.websocketonopen;this.websock.onerror=this.websocketonerror;this.websock.onmessage=this.websocketonmessage;this.websock.onclose=this.websocketclose;constthat=this;that.loading=true;GET({url:'/api/personal/web/message/socketData?pageNo=1',callback:res=>{if(res.code===200){that.messages=res.data.messages;that.hasMore=res.data.messages.length===that.pager.pageSize;that.$nextTick(function(){document.getElementById("socket-content").scroll({top:document.getElementById("socket-content").scrollHeight,left:0,behavior:'smooth'})})}that.loading=false}})},sendMsg(data){if(/^\s*$/.test(data)){this.message='';return;}//发送时传入JSON(UID,昵称,内容)constlocal=localStorage.getItem("socketUser");if(local){constl=JSON.parse(local);this.send(l,data)}else{//弹框this.$prompt('首次发表,请输入昵称','提示',{confirmButtonText:'确定',cancelButtonText:'取消',}).then(({value})=>{//随机生成UIDconstuid=this.randomVideoUuid(32,16);constform={uid:uid,name:value,background:`rgb(${Math.random()*255},${Math.random()*255},${Math.random()*255})`};localStorage.setItem("socketUser",JSON.stringify(form));this.send(form,data)}).catch(()=>{this.$message({type:'info',message:'取消输入'});});}},send(obj,data){obj.content=data;obj.createTime=newDate().getTime();this.websock.send(JSON.stringify(obj));this.message='';this.messages.push(obj);this.$nextTick(function(){document.getElementById("socket-content").scroll({top:document.getElementById("socket-content").scrollHeight,left:0,behavior:'smooth'})})},loadMore(){this.loading=true;constthat=this;if(this.hasMore){this.pager.pageNo+=1;GET({url:'/api/personal/web/message/socketData?pageNo='+this.pager.pageNo,callback:res=>{if(res.code===200){that.messages=[...res.data.messages,...that.messages];that.hasMore=res.data.messages.length>=that.pager.pageSize;}that.loading=false;}})}},websocketonopen:function(e){console.log("WebSocket连接成功",e);this.connect=true;},websocketonerror:function(e){console.log("WebSocket连接发生错误");this.connect=false;},websocketonmessage:function(e){constda=JSON.parse(e.data);this.messages.push(da);this.$nextTick(function(){document.getElementById("socket-content").scroll({top:document.getElementById("socket-content").scrollHeight,left:0,behavior:'smooth'})})},websocketclose:function(e){console.log("connectionclosed("+e.code+")");},randomVideoUuid(len,radix){letchars='0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'.split('');letuuid=[];radix=radix||chars.length;if(len){for(leti=0;i<len;i++)uuid[i]=chars[0|Math.random()*radix];}else{letr;uuid[8]=uuid[13]=uuid[18]=uuid[23]='-';uuid[14]='4';for(leti=0;i<36;i++){if(!uuid[i]){r=0|Math.random()*16;uuid[i]=chars[(i===19)?(r&0x3)|0x8:r];}}}returnuuid.join('');},},mounted(){this.initWebSocket();}}</script>本段代码为简单的Vue实现的网页聊天室代码,其中@/api为自己简单封装的JS函数,用户初次进入页面时会生成一个随机UID保存到localStorage中,在mounted周期中初始化websocket连接。本聊天室最终效果地址：https://web.coralcloud.cn/blog/message
Centos安装ApacheHadoop2.7.7准备文件:hadoop-2.7.7.tar.gz一、安装JDK安装Hadoop之前需要保证JDK8成功安装java-version二、上传Hadoop压缩包上传成功后解压文件：tar-zxvfhadoop-2.7.7.tar.gz假设解压后的Hadoop目录为:/home/hadoop/hadoop-2.7.7注意配置HADOOP_HOME环境变量exportHADOOP_HOME=/home/hadoop/hadoop-2.7.7exportPATH=$PATH:$HADOOP_HOME/bin:$HADOOP_HOME/sbin三、配置服务器免密登录$ssh-keygen-trsa-P''-f~/.ssh/id_rsa$cat~/.ssh/id_rsa.pub>>~/.ssh/authorized_keys$chmod0600~/.ssh/authorized_keys执行完成后:sshmaster命令则能够跳过输入密码阶段直接连接四、修改配置==配置文件所在位置:$HADOOP_HOME/etc/hadoop==core-size.xml<configuration><property><name>fs.defaultFS</name><value>hdfs://master:9000</value></property></configuration>hdfs-size.xml<configuration><property><name>dfs.replication</name><value>1</value></property></configuration>mapred-site.xml<configuration><property><name>mapreduce.framework.name</name><value>yarn</value></property><property><name>mapreduce.application.classpath</name><value>$HADOOP_MAPRED_HOME/share/hadoop/mapreduce/*:$HADOOP_MAPRED_HOME/share/hadoop/mapreduce/lib/*</value></property></configuration>yarn-site.xml<configuration><property><name>yarn.nodemanager.aux-services</name><value>mapreduce_shuffle</value></property><property><name>yarn.nodemanager.env-whitelist</name><value>JAVA_HOME,HADOOP_COMMON_HOME,HADOOP_HDFS_HOME,HADOOP_CONF_DIR,CLASSPATH_PREPEND_DISTCACHE,HADOOP_YARN_HOME,HADOOP_MAPRED_HOME</value></property></configuration>五、启动初始化HDFShdfsnamenode-format启动HDFSstart-dfs.sh启动YARNstart-yarn.sh启动成功后访问http://master:50070查看HDFS状态六、相关命令start-dfs.sh启动HDFS(namenode/datanode/SecondaryNamenode)stop-dfs.sh停止HDFSstart-yarn.sh启动Yarnstop-yarn.sh停止Yarnstart-all.sh启动HDFS和Yarnstop-all.sh停止HDFS和Yarn
采集节点主要安装Filebeat组件即可，Filebeat可以很简单运行在Windows/Linux操作系统上，不需要其余环境。下载Filebeat压缩包:https://www.elastic.co/downloads/past-releases/filebeat-6-2-4根据操作系统选择对应的版本下载解压修改目录下filebeat.yml文件，具体配置下图：上图为filebeat的输入端配置，指定监听文件上图为filebeat的输出端配置，指定输出到本机的Logstash中Filebeat启动（cd$FILEBEAT_HOME）：./filebeat-e-cfilebeat.yml后台启动可使用nohup命令nohup./filebeat-e-cfilebeat.yml-d"publish">logs/filebeat.log2>&1&
下载破解文件JetbrainsIdesCrack-3.4.jar将下载的文件复制到WebStorm安装文件夹下的bin文件夹下(在桌面上WebStorm快捷方式上右键【打开文件所在的位置】可直接进入)双击打开WebStorm进入激活页面,点选【Evaluateforfree】试用30天,进入应用界面在菜单【Help】->【EditcustomVMoptions..】点击打开配置文件.在配置文件最下方加入一行:-javaagent:D:\software\WebStorm2019.1.3\bin\JetbrainsIdesCrack-3.4.jar这里的文件路径具体指向到刚才复制的破解文件路径下在菜单【Help】->【Register...】点击打开激活页面,选择【licenseserver】激活方式,在下面输入框中填写:https://fls.jetbrains-agent.com点击【Activate】激活后,重启WebStorm生效.
一、Sharding-jdbc简介Sharding-jdbc是开源的数据库操作中间件；定位为轻量级Java框架，在Java的JDBC层提供的额外服务。它使用客户端直连数据库，以jar包形式提供服务，无需额外部署和依赖，可理解为增强版的JDBC驱动，完全兼容JDBC和各种ORM框架。官方文档地址：https://shardingsphere.apache.org/document/current/cn/overview/本文demo实现了分库分表功能。作者能力有限，如有错误，欢迎各位在评论中指出。不胜感激！二、项目结构首先创建一个一般的Springboot项目，项目采用三层架构，结构图如下：项目目录结构图POM.xml文件如下：<?xmlversion="1.0"encoding="UTF-8"?><projectxmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.1.6.RELEASE</version><relativePath/><!--lookupparentfromrepository--></parent><groupId>com.macky</groupId><artifactId>spring-boot-shardingjdbc</artifactId><version>0.0.1-SNAPSHOT</version><name>spring-boot-shardingjdbc</name><description>Demoprojectforspring-boot-shardingjdbc</description><properties><java.version>1.8</java.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><!--mysql--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><scope>runtime</scope></dependency><!--Mybatis-Plus--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.1.1</version></dependency><!--shardingspherestart--><!--forspringboot--><dependency><groupId>io.shardingsphere</groupId><artifactId>sharding-jdbc-spring-boot-starter</artifactId><version>3.1.0</version></dependency><!--forspringnamespace--><dependency><groupId>io.shardingsphere</groupId><artifactId>sharding-jdbc-spring-namespace</artifactId><version>3.1.0</version></dependency><!--shardingsphereend--><!--lombok--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>实体类以书本为例packagecom.macky.springbootshardingjdbc.entity;importcom.baomidou.mybatisplus.annotation.TableName;importcom.baomidou.mybatisplus.extension.activerecord.Model;importgroovy.transform.EqualsAndHashCode;importlombok.Data;importlombok.experimental.Accessors;/***@authorMacky*@TitleclassBook*@Description:书籍是实体类*@date2019/7/1315:23*/@Data@EqualsAndHashCode(callSuper=true)@Accessors(chain=true)@TableName("book")publicclassBookextendsModel<Book>{privateintid;privateStringname;privateintcount;}开放保存和查询两个接口，代码如下：packagecom.macky.springbootshardingjdbc.controller;importcom.macky.springbootshardingjdbc.entity.Book;importcom.macky.springbootshardingjdbc.service.BookService;importorg.springframework.beans.factory.annotation.Autowired;importorg.springframework.web.bind.annotation.*;importjava.util.List;/***@authorMacky*@TitleclassBookController*@Description:TODO*@date2019/7/1220:53*/@RestControllerpublicclassBookController{@AutowiredBookServicebookService;@RequestMapping(value="/book",method=RequestMethod.GET)publicList<Book>getItems(){returnbookService.getBookList();}@RequestMapping(value="/book",method=RequestMethod.POST)publicBooleansaveItem(Bookbook){returnbookService.save(book);}}BookServiceImpl.javapackagecom.macky.springbootshardingjdbc.service.impl;importcom.baomidou.mybatisplus.core.toolkit.Wrappers;importcom.baomidou.mybatisplus.extension.service.impl.ServiceImpl;importcom.macky.springbootshardingjdbc.entity.Book;importcom.macky.springbootshardingjdbc.mapper.BookMapper;importcom.macky.springbootshardingjdbc.service.BookService;importorg.springframework.stereotype.Service;importjava.util.List;/***@authorMacky*@TitleclassBookServiceImpl*@Description:TODO*@date2019/7/1220:47*/@ServicepublicclassBookServiceImplextendsServiceImpl<BookMapper,Book>implementsBookService{@OverridepublicList<Book>getBookList(){returnbaseMapper.selectList(Wrappers.<Book>lambdaQuery());}@Overridepublicbooleansave(Bookbook){returnsuper.save(book);}}BookMapper.javapackagecom.macky.springbootshardingjdbc.mapper;importcom.baomidou.mybatisplus.core.mapper.BaseMapper;importcom.macky.springbootshardingjdbc.entity.Book;/***@authorMacky*@TitleclassBookMapper*@Description:TODO*@date2019/7/1220:46*/publicinterfaceBookMapperextendsBaseMapper<Book>{}创建数据库表，DDL语句如下:#创建数据库表数据CREATEDATABASEIFNOTEXISTS`db0`;USE`db0`;DROPTABLEIFEXISTS`book_0`;CREATETABLE`book_0`(`id`INT(11)NOTNULL,`name`VARCHAR(255)DEFAULTNULL,`count`INT(11)DEFAULTNULL,PRIMARYKEY(`id`))ENGINE=INNODBDEFAULTCHARSET=utf8mb4;DROPTABLEIFEXISTS`book_1`;CREATETABLE`book_1`(`id`INT(11)NOTNULL,`name`VARCHAR(255)DEFAULTNULL,`count`INT(11)DEFAULTNULL,PRIMARYKEY(`id`))ENGINE=INNODBDEFAULTCHARSET=utf8mb4;CREATEDATABASEIFNOTEXISTS`db1`;USE`db1`;DROPTABLEIFEXISTS`book_0`;CREATETABLE`book_0`(`id`INT(11)NOTNULL,`name`VARCHAR(255)DEFAULTNULL,`count`INT(11)DEFAULTNULL,PRIMARYKEY(`id`))ENGINE=INNODBDEFAULTCHARSET=utf8mb4;DROPTABLEIFEXISTS`book_1`;CREATETABLE`book_1`(`id`INT(11)NOTNULL,`name`VARCHAR(255)DEFAULTNULL,`count`INT(11)DEFAULTNULL,PRIMARYKEY(`id`))ENGINE=INNODBDEFAULTCHARSET=utf8mb4;CREATEDATABASEIFNOTEXISTS`db2`;USE`db2`;DROPTABLEIFEXISTS`book_0`;CREATETABLE`book_0`(`id`INT(11)NOTNULL,`name`VARCHAR(255)DEFAULTNULL,`count`INT(11)DEFAULTNULL,PRIMARYKEY(`id`))ENGINE=INNODBDEFAULTCHARSET=utf8mb4;DROPTABLEIFEXISTS`book_1`;CREATETABLE`book_1`(`id`INT(11)NOTNULL,`name`VARCHAR(255)DEFAULTNULL,`count`INT(11)DEFAULTNULL,PRIMARYKEY(`id`))ENGINE=INNODBDEFAULTCHARSET=utf8mb4;配置分库分表策略application.properties：#数据源db0,db1,db2sharding.jdbc.datasource.names=db0,db1,db2#第一个数据库sharding.jdbc.datasource.db0.type=com.zaxxer.hikari.HikariDataSourcesharding.jdbc.datasource.db0.driver-class-name=com.mysql.cj.jdbc.Driversharding.jdbc.datasource.db0.jdbc-url=jdbc:mysql://localhost:3306/db0?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTCsharding.jdbc.datasource.db0.username=rootsharding.jdbc.datasource.db0.password=Aa123456#第二个数据库sharding.jdbc.datasource.db1.type=com.zaxxer.hikari.HikariDataSourcesharding.jdbc.datasource.db1.driver-class-name=com.mysql.cj.jdbc.Driversharding.jdbc.datasource.db1.jdbc-url=jdbc:mysql://localhost:3306/db1?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTCsharding.jdbc.datasource.db1.username=rootsharding.jdbc.datasource.db1.password=Aa123456#第三个数据库sharding.jdbc.datasource.db2.type=com.zaxxer.hikari.HikariDataSourcesharding.jdbc.datasource.db2.driver-class-name=com.mysql.cj.jdbc.Driversharding.jdbc.datasource.db2.jdbc-url=jdbc:mysql://localhost:3306/db2?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTCsharding.jdbc.datasource.db2.username=rootsharding.jdbc.datasource.db2.password=Aa123456#水平拆分的数据库（表）配置分库+分表策略行表达式分片策略#分库策略sharding.jdbc.config.sharding.default-database-strategy.inline.sharding-column=idsharding.jdbc.config.sharding.default-database-strategy.inline.algorithm-expression=db$->{id%3}#分表策略其中book为逻辑表分表主要取决于id行sharding.jdbc.config.sharding.tables.book.actual-data-nodes=db$->{0..2}.book_$->{0..2}sharding.jdbc.config.sharding.tables.book.table-strategy.inline.sharding-column=count#分片算法表达式sharding.jdbc.config.sharding.tables.book.table-strategy.inline.algorithm-expression=book_$->{count%3}#主键UUID18位数如果是分布式还要进行一个设置防止主键重复#sharding.jdbc.config.sharding.tables.user.key-generator-column-name=id#打印执行的数据库以及语句sharding.jdbc.config.props..sql.show=truespring.main.allow-bean-definition-overriding=true#读写分离sharding.jdbc.datasource.dsmaster=接口测试使用postman示例：GET请求------>http://localhost:8080/bookPOST请求：------->http://localhost:8080/book?id=1&name=java编程思想&count=8demo的github地址：https://github.com/Macky-He/spring-boot--shardingsphere-examples如各位觉得有帮助的话，还请给个star鼓励鼓励博主，谢谢！三、总结分库分表实现按照官方文档做一个demo是第一步，如需深入还需要研究源码，研究架构，研究思想；此文仅作为入门demo搭建指南，如需深入理解，还请移步至官方文档。参考资料1.官方文档：https://shardingsphere.apache.org/document/current/cn/manual/sharding-jdbc/usage/sharding/
一、安装Redis1.下载Rediswgethttp://download.redis.io/releases/redis-4.0.6.tar.gz2.解压tar-zxvfredis-4.0.6.tar.gz3.yum安装gccyuminstall-ygcc4.编译安装rediscdredis-4.0.6makeMALLOC=libccdsrc&&makeinstall二、启动Redis1.在/etc目录下新建redis目录mkdir-p/etc/redis2.将/usr/local/redis-4.0.6/redis.conf文件复制一份到/etc/redis目录下，并命名为6379.confcp/usr/local/redis-4.0.6/redis.conf/etc/redis/6379.conf3.将redis的启动脚本复制一份放到/etc/init.d目录下cp/usr/local/redis-4.0.6/utils/redis_init_script/etc/init.d/redisd4.设置redis开机自启动cd/etc/init.dchkconfigredisdonserviceredisddoesnotsupportchkconfig看结果是redisd不支持chkconfig,编辑redisd文件,加入如下注释:#chkconfig:23459010#description:Redisisapersistentkey-valuedatabasechkconfigredisdon启动redis:serviceredisdstart停止redis:serviceredisdstop
1.@Component,@Service,@Controller,@Repository是spring注解，注解后可以被spring框架所扫描并注入到spring容器来进行管理2.@Component是通用注解，其他三个注解是这个注解的拓展，并且具有了特定的功能3.如果想使用自定义的组件注解，那么只要在你定义的新注解中加上@Component即可:4.@Repository注解在持久层中，具有将数据库操作抛出的原生异常翻译转化为spring的持久层异常的功能。5.@Controller层是spring-mvc的注解，具有将请求进行转发，重定向的功能。6.@Service层是业务逻辑层注解，这个注解只是标注该类处于业务逻辑层。7.用这些注解对应用进行分层之后，就能将请求处理，义务逻辑处理，数据库操作处理分离出来，为代码解耦，也方便了以后项目的维护和开发。
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