[Java知识库]Nacos使用，集成OpenFeign远程下载文件

nacos依赖

<!--向Nacos注册自身信息-->
<dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            <version>2.2.6.RELEASE</version>
</dependency>
<!--配置中心,启动从注册中心下载yaml等配置文件覆盖本地application.yml-->
<dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
            <version>2.2.6.RELEASE</version>
</dependency>

yml配置

新建一个bootstrap.yml与application.yml同级目录

bootstrap.yml内容:

spring:
  application:
    name: server-user
  profiles:
    active: dev #nacos的配置文件的后缀,可以是prod，dev等等不同运行环境的后缀
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #nacos注册地址
      config:
        server-addr: localhost:8848 #nacos拉取配置文件地址
        file-extension: yaml #配置文件类型，可以是properties，yaml等

启动类注解

启动类加上注解
@EnableDiscoveryClient

刷新配置

@RefreshScope 用在需要读取yaml配置参数的类，只能刷新普通备至参数，不能使系统真实开放端口改变
比如 @Value("${server.port:1000}")
在nacos修改配置端口后，程序之前开放的端口依然不变，但是@Value注入的值会变

OpenFeign配置

依赖

<!--向Nacos注册自身信息-->
<dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            <version>2.2.6.RELEASE</version>
</dependency>
<!--openfeign-->
<dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
            <version>2.2.6.RELEASE</version>
</dependency>

spring:
  application:
    name: server-user

启动类加上注解:@EnableFeignClients

@FeignClient("远程对应的服务名server-user")
public interface ServerFeign {
    @GetMapping("/getUser")
    //调用远程void方法的controller下载文件
    //Response可以用来下载文件
    Response getUser(@RequestParam("id") String id);
}

使用

@RestController
public class ServerController {
    //注入ServerFeign
    @Autowired
    private ServerFeign serverFeign;
    @GetMapping("/getUser")
    public void getUser(String id,HttpServletResponse httpServletResponse) throws IOException {
        httpServletResponse.setContentType("application/force-download");
        try {
            httpServletResponse.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode("a.txt", "UTF-8"));
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        Response response = serverFeign.getUser(id);
        InputStream inputStream = response.body().asInputStream();
        ServletOutputStream outputStream = httpServletResponse.getOutputStream();
        byte[] bytes=new byte[1024];
        int len =0;
        while ((len=(inputStream.read(bytes)))!=-1){
            outputStream.write(bytes,0,len);
            outputStream.flush();
        }
 }