nacos作为配置中心

分布式配置中心

在微服务架构中，为什么需要一个统一的配置中心呢？如果用一句话来说那就是方便管理，降低出错的可能。比如：你开发环境是一套配置，测试环境是一套，生产环境又是一套。你如果手动去修改，难免会出错吧。

Nacos

阿里开源的产品，可以作为配置中心，也可以代替Zookeeper作为服务注册中心。

下载地址：https://github.com/alibaba/nacos/releases

正题

为了方便，我在本地建立三个不同的数据库，分别代表开发环境、测试环境、生产环境的数据库。

新建一个Springboot工程，修改pom文件，引入相关依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://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>2.1.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <mysql.version>5.1.47</mysql.version>
        <druid.version>1.1.15</druid.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.boot</groupId>
            <artifactId>nacos-config-spring-boot-starter</artifactId>
            <version>0.2.1</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.0</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>${druid.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.7.0</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.7</version>
                <configuration>
                    <verbose>true</verbose>
                    <overwrite>true</overwrite>
                </configuration>
                <executions>
                    <execution>
                        <id>mybatis-generator</id>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                    </execution>
                </executions>
                <dependencies>
                    <dependency>
                        <groupId>mysql</groupId>
                        <artifactId>mysql-connector-java</artifactId>
                        <version>${mysql.version}</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>
    </build>

    <profiles>
        <profile>
            <id>dev</id>
            <properties>
                <spring.profiles>dev</spring.profiles>
            </properties>
            <activation>
                <activeByDefault>true</activeByDefault>
            </activation>
        </profile>
        <profile>
            <id>test</id>
            <properties>
                <spring.profiles>test</spring.profiles>
            </properties>
        </profile>
        <profile>
            <id>pro</id>
            <properties>
                <spring.profiles>pro</spring.profiles>
            </properties>
        </profile>
    </profiles>

</project>

先来看一下最终目录结构：

generatorConfig.xml是用来自动生成Mapper文件的，logback是用来生成日志的，config包里面是读取nocas上面的配置的，其他都是简单的东西。

-------------------------------------------

generatorConfig.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN" "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd" >

<generatorConfiguration>
    <context id="context1">

        <!-- 这里引入扩展插件 -->
        <plugin type="org.mybatis.generator.plugins.UnmergeableXmlMappersPlugin"/>

        <commentGenerator>
            <!--  关闭自动生成的注释  -->
            <property name="suppressAllComments" value="true"/>
        </commentGenerator>


        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/mytest?useSSL=false"
                        userId="root"
                        password="1234"/>
        <javaModelGenerator targetPackage="com.example.demo.model"
            targetProject="src/main/java" />
        <sqlMapGenerator targetPackage="mapper" targetProject="src/main/resources" />
        <javaClientGenerator targetPackage="com.example.demo.dao"
            targetProject="src/main/java" type="XMLMAPPER" />

        <!--数据库的表名-->
        <table tableName="user">
            <generatedKey column="id" sqlStatement="MySql" identity="true" />
        </table>

       </context>
   </generatorConfiguration>

在这里双击运行即可生成需要的java类。

选择这里可以切换环境

logback-spring.xml

<?xml version="1.0" encoding="UTF-8" ?>
<configuration scan="true" scanPeriod="60 seconds">
    <springProperty scope="context" name="LOG_HOME" source="logging.path"/>
    
    <springProfile name="dev,test,pro">
        <!--格式化输出：%d表示日期，%thread表示线程名，%-5level：级别从左显示5个字符宽度%msg：日志消息，%n是换行符 -->
        <property name="log_pattern" value="%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger Line:%-3L - %msg%n"/>
    </springProfile>

    <appender name="app" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <File>${LOG_HOME}/app.log</File>
        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
            <pattern>${log_pattern}</pattern>
        </encoder>
        <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
            <level>INFO</level>
        </filter>
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <FileNamePattern>${LOG_HOME}/app.%d{yyyy-MM-dd}.log</FileNamePattern>
            <!--日志文件保留天数 -->
            <MaxHistory>30</MaxHistory>
        </rollingPolicy>
    </appender>

    <appender name="app-error" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <File>${LOG_HOME}/app_error.log</File>
        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
            <pattern>%d{yyyy-MM-dd HH:mm:ss} [%thread] [%-5level] [%logger:%L] %msg [TxId:%X{PtxId},SpanId:%X{PspanId}]%n</pattern>
        </encoder>
        <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
            <level>ERROR</level>
        </filter>
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <FileNamePattern>${LOG_HOME}/app_error.%d{yyyy-MM-dd}.log</FileNamePattern>
        </rollingPolicy>
    </appender>

    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <outputPatternAsHeader>true</outputPatternAsHeader>
            <pattern>%black(%d{yyyy-MM-dd HH:mm:ss}) %highlight(%-6level) %black([%thread]) %boldCyan(%logger) %boldMagenta(#%method %-3L) : %black(%msg%n)</pattern>
        </encoder>
    </appender>

    <!-- 开发环境 -->
    <springProfile name="dev">
        <logger name="org" level="INFO"/>
        <!-- level: FATAL,ERROR,WARN,INFO,DEBUG,TRACE -->
        <root level="DEBUG">
            <appender-ref ref="CONSOLE"/>
            <appender-ref ref="app"/>
            <appender-ref ref="app-error"/>
        </root>
    </springProfile>

    <!-- 测试&生产环境 -->
    <springProfile name="test,pro">
        <logger name="org" level="INFO"/>
        <root level="INFO">
            <appender-ref ref="app"/>
            <appender-ref ref="app-error"/>
        </root>
    </springProfile>
</configuration>

application.yml

spring:
  profiles:
    active: @spring.profiles@
logging:
  config: classpath:logback-spring.xml

下面打开nacos，做一下不同环境的配置

新建三个命名空间，之后进入配置管理页面，可以看到多了三个页签。

在每一个页签下添加我们需要的配置即可。（注意不同环境的数据库不一样）

url=jdbc:mysql://localhost:3306/mytest_pro?useSSL=false&useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&rewriteBatchedStatements=true
user_name=root
password=1234
driver_class_name=com.mysql.jdbc.Driver

不同的命名空间有不同的命名空间ID，这个有用，我们下一步会用到

属性文件的namespace填写对应的命名空间ID

application-dev.yml

server:
  port: 8080
  address: 0.0.0.0
nacos:
  config:
    server-addr: localhost:8848
    namespace: 0d5b0e7c-485c-469b-9b3c-eb20dc9d9bb1
logging:
  path: "./logs"

application-test.yml

server:
  port: 8080
  address: 0.0.0.0
nacos:
  config:
    server-addr: localhost:8848
    namespace: b49147ed-72de-45e9-8d90-34644585a000
logging:
  path: /AppLogs/boot-nacos-test

application-pro.yml

server:
  port: 8080
  address: 0.0.0.0
nacos:
  config:
    server-addr: localhost:8848
    namespace: 5fb0883c-2db7-4344-9883-0394edb5c858
logging:
  path: /AppLogs/boot-nacos

DatabaseConfig

package com.example.demo.config;

import com.alibaba.nacos.api.config.annotation.NacosValue;
import com.alibaba.nacos.spring.context.annotation.config.NacosPropertySource;
import org.springframework.stereotype.Component;


@Component
@NacosPropertySource(dataId = "database",groupId = "DEFAULT_GROUP",autoRefreshed = true)
public class DatabaseConfig {

    @NacosValue(value = "${driver_class_name}", autoRefreshed = true)
    private String driverClassName;

    @NacosValue(value = "${url}", autoRefreshed = true)
    private String url;

    @NacosValue(value = "${user_name}", autoRefreshed = true)
    private String username;

    @NacosValue(value = "${password}", autoRefreshed = true)
    private String password;

    public String getDriverClassName() {
        return driverClassName;
    }

    public String getUrl() {
        return url;
    }

    public String getUsername() {
        return username;
    }

    public String getPassword() {
        return password;
    }

}

MybatisConfiguration

package com.example.demo.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages={"com.example.demo.dao"})
public class MybatisConfiguration {
    @Autowired
    private DatabaseConfig dataBaseConfig;

    @Bean
    public DataSource dataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(dataBaseConfig.getDriverClassName());
        dataSource.setUrl(dataBaseConfig.getUrl());
        dataSource.setUsername(dataBaseConfig.getUsername());
        dataSource.setPassword(dataBaseConfig.getPassword());
        return dataSource;
    }

    @Bean
    public SqlSessionFactory sqlSessionFactoryBean() throws Exception {

        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource());
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        sqlSessionFactoryBean.setMapperLocations(resolver.getResources("classpath:mapper/*.xml"));

        return sqlSessionFactoryBean.getObject();
    }

}

UserService

package com.example.demo.service;

import com.example.demo.model.User;

import java.util.List;


public interface UserService {

    List<User> getUserList();
}

UserServiceImpl

package com.example.demo.service.impl;

import com.example.demo.dao.UserMapper;
import com.example.demo.model.User;
import com.example.demo.model.UserExample;
import com.example.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;


@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserMapper userMapper;

    @Override
    public List<User> getUserList() {
        UserExample example = new UserExample();
        return userMapper.selectByExample(example);
    }
}

UserController

package com.example.demo.controller;

import com.example.demo.model.User;
import com.example.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;


@RestController
public class UserController {

    @Autowired
    private UserService userService;

    @RequestMapping("/users")
    public List<User> getUsers(){
        return userService.getUserList();
    }
}