负载均衡spring-cloud-starter-openfeign教程

pom.xml

<?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>3.5.5</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><url/><licenses><license/></licenses><developers><developer/></developers><scm><connection/><developerConnection/><tag/><url/></scm><properties><java.version>17</java.version><spring-cloud.version>2025.0.0</spring-cloud.version></properties><dependencies><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>3.0.5</version></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-openfeign</artifactId></dependency><dependency><groupId>com.mysql</groupId><artifactId>mysql-connector-j</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><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter-test</artifactId><version>3.0.5</version><scope>test</scope></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency></dependencies><dependencyManagement><dependencies><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-dependencies</artifactId><version>${spring-cloud.version}</version><type>pom</type><scope>import</scope></dependency></dependencies></dependencyManagement><!--  <build>-->
<!--    <plugins>-->
<!--      <plugin>-->
<!--        <groupId>org.apache.maven.plugins</groupId>-->
<!--        <artifactId>maven-compiler-plugin</artifactId>-->
<!--        <version>3.8.1</version>-->
<!--        <configuration>-->
<!--          <source>17</source>  &lt;!&ndash; 需与项目JDK版本一致 &ndash;&gt;-->
<!--          <target>17</target>-->
<!--          <encoding>UTF-8</encoding>-->
<!--        </configuration>-->
<!--      </plugin>-->
<!--    </plugins>-->
<!--  </build>--><build><plugins><plugin><groupId>org.codehaus.mojo</groupId><artifactId>appassembler-maven-plugin</artifactId><version>2.1.0</version><!-- 如果不配置 generate-daemons，则打包命令为 mvn clean package appassembler:assemble --><!-- 如果配置了 generate-daemons，打包命令可以是 mvn clean package 也可以是 mvn clean package appassembler:assemble --><executions><execution><id>make-assembly</id><phase>package</phase><goals><goal>assemble</goal></goals></execution></executions><configuration><!-- flat与lib共同决定将项目用的的所有jar包复制到lib目录下 --><repositoryLayout>flat</repositoryLayout><!--从哪里copy配置文件--><configurationSourceDirectory>src/main/resources</configurationSourceDirectory><includeConfigurationDirectoryInClasspath>true</includeConfigurationDirectoryInClasspath><!--是否copy配置文件--><copyConfigurationDirectory>true</copyConfigurationDirectory><!--生成的项目的目录位置，这里的client是项目的名称，你可以根据你的需要自己随便命名--><assembleDirectory>${project.build.directory}/client</assembleDirectory><!--配置文件存放在conf目录路径--><configurationDirectory>conf</configurationDirectory><!-- 打包的jar，以及maven依赖的jar放到这个目录里面 --><repositoryName>lib</repositoryName><!-- 可执行脚本的目录 --><binFolder>bin</binFolder><!-- 生成linux, windows两种平台的执行脚本 --><platforms><platform>windows</platform><platform>unix</platform></platforms><!-- 针对不同平台生成不同类型的启动脚本 --><binFileExtensions><unix>.sh</unix><windows>.bat</windows></binFileExtensions><!--编码，日志--><encoding>UTF-8</encoding><logsDirectory>logs</logsDirectory><tempDirectory>tmp</tempDirectory><!--java启动参数--><extraJvmArguments>-Xms128m</extraJvmArguments><programs><program><!--指定主类，脚本名。会生成shell/bat两种类型,也可用platforms指定运行平台--><mainClass>com.example.demo.OpenFeignApplication</mainClass><!-- 生成的脚本文件的名称，比如start.sh,你也可以根据你的需要命名成其他名字 --><name>start</name></program></programs></configuration></plugin></plugins></build>
</project>

2、application.yml

server:port: 8088
spring:datasource:url: jdbc:mysql://localhost:3306/wscobusername: rootpassword: 123456driver-class-name: com.mysql.cj.jdbc.Driver
logging:level:root: DEBUG

3、启动项

@SpringBootApplication (scanBasePackages = {"com.example.controller","com.example.imp"})
@EnableFeignClients(basePackages = "com.example.imp")
public class OpenFeignApplication {public static void main(String[] args) {SpringApplication.run(OpenFeignApplication.class, args);}}

4、访问FeignClient配置

@FeignClient(name = "${user.service.name}", url = "${user.service.url}")
public interface UserServiceClient {@GetMapping("/hello")String sayHello();}

4、application.properties

spring.application.name=demo
user.service.name=user-service
user.service.url=http://localhost:9081

5、controller层

@RestController
public class MyController {@Autowiredprivate UserServiceClient feignClient;@GetMapping("/get-data")public String getData() {return feignClient.sayHello();}
}