Nacos在spring boot的使用

说明：本文章是自己在学习spring boot中使用Nacos服务注册和发现时记录的当做笔记了，有什么不对的欢迎指正。

当你来搜索spring boot中使用nacos的时候就应该知道nacos是什么了，这里就不多废话了，直接看下面的使用吧

1、服务注册：

步骤：

1、去官网安装nacos并且启动nacos service.

成功的页面如下：

进入里面的的网页可以看到如下界面：

2、建立spring boot项目引入相关依赖jar包

<!--        spring boot 核心依赖--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency>
<!--        spring boot测试依赖--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency>
<!--        nacos注册依赖--><dependency><groupId>com.alibaba.boot</groupId><artifactId>nacos-discovery-spring-boot-starter</artifactId><version>0.2.12</version></dependency></dependencies>

3、使项目启动自动注册到服务中心

1、通过配置实现（更推荐，下面的案例也是写yml文件来配置）

server:port: 8081ip: localhost
spring:application:name: userserver
nacos:discovery:# 设置自动注册，默认是falseauto-register: true# nacos server的ip和端口server-addr: localhost:8848

启动项目后可以在nacos server看的如下界面，已经注册到了服务中心

2、写配置类（依然需要在配置文件中设置nacos server的ip和端口）

package com.example.config;import com.alibaba.nacos.api.annotation.NacosInjected;
import com.alibaba.nacos.api.exception.NacosException;
import com.alibaba.nacos.api.naming.NamingService;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;import javax.annotation.PostConstruct;/*** Created by IntelliJ IDEA.** @Author : wlh* @create 2023/1/18 18:15*/
@Configuration
public class NacosRegisterConfig {// 服务名称@Value("${spring.application.name}")private String applicationName;// 服务的端口号@Value("${server.port}")private Integer port;// 服务ip地址@Value("${server.ip}")private String ip;@NacosInjectedprivate NamingService namingService;// @PostConstruct 在依赖注入完成时执行注解的方法@PostConstructpublic void register() throws NacosException {namingService.registerInstance(applicationName,ip,port);}
}

然后在启动类上写上注解@EnableNacosDiscovery。执行后一样的可以在nacos server里面看到注册的服务。
但是需要注意的是：使用配置文件的形式在启动类上是不需要@EnableNacosDiscovery注解的，用了反而注册不上

2、服务发现和调用：

1、获取服务：
使用NamingService对象的selectOneHealthyInstance(“服务名称”);获取一个服务，参数是服务名称。这个方法的作用是根据参数获取对应的服务，如果有多个（集群时）会自己去调用一个（要不是随机的，要不是轮询调度）。
2、远程调用：
RestTemplate对象的方法能够实现远程调用
getForObject — optionsForAllow 分为一组，这类方法是常规的 Rest API（GET、POST、DELETE 等）方法调用；
exchange：接收一个 RequestEntity 参数，可以自己设置 HTTP method，URL，headers 和 body，返回 ResponseEntity；
execute：通过 callback 接口，可以对请求和返回做更加全面的自定义控制。
如下：

    public UserDto queryById(Integer id) throws NacosException {User user = userMapper.selectById(id);UserDto userDto = new UserDto();userDto.setId(user.getId());userDto.setName(user.getName());userDto.setMoney(user.getMoney());// 获取服务Instance logserver = namingService.selectOneHealthyInstance("logserver");String url = String.format("http://%s:%d/userLog/queryByUserId/"+id,logserver.getIp(),logserver.getPort());// 通过restTemplate对象进行跨模块请求数据List list = restTemplate.getForObject(url, List.class);userDto.setUserLogs(list);return userDto;}

3、完整案例

需求：写两个服务，一个user服务，一个user_log服务，在user服务获取用户信息时我们需要调用user_log服务来获取对应用户的日志列表。
数据库数据准备
表1：user

表2：user_log

user服务：

引入依赖：

<groupId>ikiku.space</groupId>
<artifactId>user-server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>user_server</name>
<description>user_server</description>

<?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 https://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>2.5.1</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>ikiku.space</groupId><artifactId>user-server</artifactId><version>0.0.1-SNAPSHOT</version><name>user_server</name><description>user_server</description><properties><java.version>8</java.version></properties><dependencies>
<!--        spring boot 核心依赖--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency>
<!--        spring boot测试依赖--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency>
<!--        mysql驱动依赖--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId></dependency>
<!--        mybatis-plus依赖--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.5.2</version></dependency>
<!--        mybatis代码生成器依赖--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-generator</artifactId><version>3.5.2</version></dependency>
<!--        模板--><!-- https://mvnrepository.com/artifact/org.freemarker/freemarker --><dependency><groupId>org.freemarker</groupId><artifactId>freemarker</artifactId><version>2.3.31</version></dependency>
<!--        lombok--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency>
<!--        swager注解依赖--><dependency><groupId>io.springfox</groupId><artifactId>springfox-swagger-ui</artifactId><version>2.9.2</version></dependency><dependency><groupId>io.springfox</groupId><artifactId>springfox-swagger2</artifactId><version>2.9.2</version></dependency>
<!--        nacos注册依赖--><dependency><groupId>com.alibaba.boot</groupId><artifactId>nacos-discovery-spring-boot-starter</artifactId><version>0.2.12</version></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>

yml文件

server:# 端口port: 8081# ipip: localhost
spring:application:name: userserver #服务的名称# 连接数据库的数据源datasource:driver-class-name: com.mysql.cj.jdbc.Driverusername: rootpassword: 123456url: jdbc:mysql://localhost:3306/db2?allowMultiQueries=true&useUnicode=true&characterEncoding=UTF-8&useSSL=false
nacos:discovery:
#    自动注册auto-register: true# nacos服务地址server-addr: localhost:8848

controller层：

package com.example.controller;import com.alibaba.nacos.api.exception.NacosException;
import com.example.dto.UserDto;
import com.example.service.UserLogService;
import com.example.service.UserService;
import jdk.nashorn.internal.ir.ReturnNode;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;/*** <p>*  前端控制器* </p>** @author wlh* @since 2023-01-18*/
@RestController
@RequestMapping("/user")
public class UserController {@Autowiredprivate UserService userService;@GetMapping("/query/{id}")public UserDto queryById(@PathVariable("id") Integer id) throws NacosException {return userService.queryById(id);}
}

config层

package com.example.config;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;/*** Created by IntelliJ IDEA.** @Author : wlh* @create 2023/1/18 17:20*/
@Configuration
public class NacosConfig {// 注入RestTemplate对象@Beanpublic RestTemplate restTemplate(){return new RestTemplate();}
}

service层

package com.example.service;import com.alibaba.nacos.api.exception.NacosException;
import com.example.dto.UserDto;
import com.example.entity.User;
import com.baomidou.mybatisplus.extension.service.IService;/*** <p>*  服务类* </p>** @author wlh* @since 2023-01-18*/
public interface UserService extends IService<User> {// 根据id获取用户信息和日志列表UserDto queryById(Integer id) throws NacosException;
}

service实现类

package com.example.service.impl;import com.alibaba.nacos.api.annotation.NacosInjected;
import com.alibaba.nacos.api.exception.NacosException;
import com.alibaba.nacos.api.naming.NamingService;
import com.alibaba.nacos.api.naming.pojo.Instance;
import com.example.dto.UserDto;
import com.example.entity.User;
import com.example.entity.UserLog;
import com.example.mapper.UserMapper;
import com.example.service.UserLogService;
import com.example.service.UserService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;import javax.annotation.Resource;
import java.util.List;/*** <p>*  服务实现类* </p>** @author wlh* @since 2023-01-18*/
@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService {@Resourceprivate UserMapper userMapper;@Autowiredprivate RestTemplate restTemplate;@NacosInjectedprivate NamingService namingService;@Overridepublic UserDto queryById(Integer id) throws NacosException {User user = userMapper.selectById(id);UserDto userDto = new UserDto();userDto.setId(user.getId());userDto.setName(user.getName());userDto.setMoney(user.getMoney());// 获取服务Instance logserver = namingService.selectOneHealthyInstance("logserver");String url = String.format("http://%s:%d/userLog/queryByUserId/"+id,logserver.getIp(),logserver.getPort());// 通过restTemplate对象进行夸模块请求数据List list = restTemplate.getForObject(url, List.class);userDto.setUserLogs(list);return userDto;}
}

mapper层

package com.example.mapper;import com.example.entity.User;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;/*** <p>*  Mapper 接口* </p>** @author wlh* @since 2023-01-18*/
public interface UserMapper extends BaseMapper<User> {}

实体类

user类

package com.example.entity;import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import java.io.Serializable;
import java.math.BigDecimal;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Getter;
import lombok.Setter;
import lombok.experimental.Accessors;/*** <p>* * </p>** @author wlh* @since 2023-01-18*/
@Getter
@Setter
@Accessors(chain = true)
@TableName("user")
@ApiModel(value = "User对象", description = "")
public class User implements Serializable {private static final long serialVersionUID = 1L;@ApiModelProperty("主键")@TableId(value = "id", type = IdType.AUTO)private Integer id;@ApiModelProperty("姓名")@TableField("name")private String name;@ApiModelProperty("账户余额")@TableField("money")private BigDecimal money;}

UserLog类

package com.example.entity;import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import java.io.Serializable;
import java.time.LocalDateTime;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Getter;
import lombok.Setter;
import lombok.experimental.Accessors;/*** <p>* * </p>** @author wlh* @since 2023-01-18*/
@Getter
@Setter
@Accessors(chain = true)
@TableName("user_log")
@ApiModel(value = "UserLog对象", description = "")
public class UserLog implements Serializable {private static final long serialVersionUID = 1L;@TableId(value = "id", type = IdType.AUTO)private Integer id;@TableField("message")private String message;@TableField("time")private LocalDateTime time;@TableField("user_id")private Integer userId;}

dto用于定义数据传输模板

package com.example.dto;import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.example.entity.UserLog;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;import java.io.Serializable;
import java.math.BigDecimal;
import java.util.List;/*** Created by IntelliJ IDEA.** @Author : wlh* @create 2023/1/18 17:12*/
@Data
public class UserDto implements Serializable {private static final long serialVersionUID = 1L;@ApiModelProperty("主键")private Integer id;@ApiModelProperty("姓名")private String name;@ApiModelProperty("账户余额")private BigDecimal money;@ApiModelProperty("日志列表")private List<UserLog> userLogs;
}

user_log服务

引入依赖

<?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 https://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>2.5.1</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>ikiku.space</groupId><artifactId>log_server</artifactId><version>0.0.1-SNAPSHOT</version><name>log_server</name><description>log_server</description><properties><java.version>8</java.version></properties><dependencies><!--        spring boot 核心依赖--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!--        spring boot测试依赖--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><!--        mysql驱动依赖--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId></dependency><!--        mybatis-plus依赖--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.5.2</version></dependency><!--        mybatis代码生成器依赖--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-generator</artifactId><version>3.5.2</version></dependency><!--        freemarker模板--><!-- https://mvnrepository.com/artifact/org.freemarker/freemarker --><dependency><groupId>org.freemarker</groupId><artifactId>freemarker</artifactId><version>2.3.31</version></dependency><!--        lombok--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency>
<!--        swagger注解依赖--><dependency><groupId>io.springfox</groupId><artifactId>springfox-swagger-ui</artifactId><version>2.9.2</version></dependency><dependency><groupId>io.springfox</groupId><artifactId>springfox-swagger2</artifactId><version>2.9.2</version></dependency>
<!--        nacos注册依赖--><dependency><groupId>com.alibaba.boot</groupId><artifactId>nacos-discovery-spring-boot-starter</artifactId><version>0.2.12</version></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>

controller层

package com.example.controller;import com.example.entity.UserLog;
import com.example.service.UserLogService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.List;/*** <p>*  前端控制器* </p>** @author wlh* @since 2023-01-18*/
@RestController
@RequestMapping("/userLog")
public class UserLogController {@Autowiredprivate UserLogService userLogService;@GetMapping("/queryByUserId/{id}")public List<UserLog> getLog(@PathVariable("id") Integer id){return userLogService.queryById(id);}
}

config层暂时不需要，如果需要跨模块访问其他的模块时，在写的和user服务里面的一样即可

yml配置

server:port: 8082ip: localhost
spring:datasource:driver-class-name: com.mysql.cj.jdbc.Driverusername: rootpassword: 123456url: jdbc:mysql://localhost:3306/db2?allowMultiQueries=true&useUnicode=true&characterEncoding=UTF-8&useSSL=falseapplication:name: logserver
nacos:discovery:auto-register: trueserver-addr: localhost:8848

service层

package com.example.service;import com.example.entity.UserLog;
import com.baomidou.mybatisplus.extension.service.IService;import java.util.List;/*** <p>*  服务类* </p>** @author wlh* @since 2023-01-18*/
public interface UserLogService extends IService<UserLog> {List<UserLog> queryById(Integer id);
}

service实现类层

package com.example.service.impl;import com.example.entity.UserLog;
import com.example.mapper.UserLogMapper;
import com.example.service.UserLogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import javax.annotation.Resource;
import java.util.List;/*** <p>*  服务实现类* </p>** @author wlh* @since 2023-01-18*/
@Service
public class UserLogServiceImpl extends ServiceImpl<UserLogMapper, UserLog> implements UserLogService {@Resourceprivate UserLogMapper userLogMapper;@Overridepublic List<UserLog> queryById(Integer id) {return userLogMapper.queryByUserId(id);}
}

mapper层

package com.example.mapper;import com.example.entity.UserLog;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;import java.util.List;/*** <p>*  Mapper 接口* </p>** @author wlh* @since 2023-01-18*/
public interface UserLogMapper extends BaseMapper<UserLog> {@Select("select  * from user_log where user_id = #{id}")List<UserLog> queryByUserId(@Param("id") Integer id);
}

实体类层

package com.example.entity;import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import java.io.Serializable;
import java.time.LocalDateTime;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Getter;
import lombok.Setter;
import lombok.experimental.Accessors;/*** <p>* * </p>** @author wlh* @since 2023-01-18*/
@Getter
@Setter
@Accessors(chain = true)
@TableName("user_log")
@ApiModel(value = "UserLog对象", description = "")
public class UserLog implements Serializable {private static final long serialVersionUID = 1L;@TableId(value = "id", type = IdType.AUTO)private Integer id;@TableField("message")private String message; @TableField("time")private LocalDateTime time;@TableField("user_id")private Integer userId;}

postman测试验证正确性

nacos服务中心

postman 发起请求测试