Feign实现文件上传下载

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Feign框架对于文件上传消息体格式并没有做原生支持，需要集成模块feign-form来实现。

独立使用Feign

添加模块依赖：

<!-- Feign框架核心 -->

<dependency>

    <groupId>io.github.openfeign</groupId>

    <artifactId>feign-core</artifactId>

    <version>11.1</version>

</dependency>

<!-- 支持表单格式，文件上传格式 -->

<dependency>

    <groupId>io.github.openfeign.form</groupId>

    <artifactId>feign-form</artifactId>

    <version>3.8.0</version>

</dependency>

<!-- 文件操作工具类 -->

<dependency>

    <groupId>commons-io</groupId>

    <artifactId>commons-io</artifactId>

    <version>2.11.0</version>

</dependency>

上传文件

定义接口：

public interface FileUploadAPI {

    // 上传文件：参数为单个文件对象

    @RequestLine("POST /test/upload/single")

    @Headers("Content-Type: multipart/form-data")

    String upload(@Param("file") File file);

    // 上传文件：参数文多个文件对象

    @RequestLine("POST /test/upload/batch")

    @Headers("Content-Type: multipart/form-data")

    String upload(@Param("files") File[] files);

    // 上传文件：参数文多个文件对象

    @RequestLine("POST /test/upload/batch")

    @Headers("Content-Type: multipart/form-data")

    String upload(@Param("files") List<File> files);

    // 上传文件：参数为文件字节数组（这种方式在服务端无法获取文件名，不要使用）

    @RequestLine("POST /test/upload/single")

    @Headers("Content-Type: multipart/form-data")

    String upload(@Param("file") byte[] bytes);

    // 上传文件：参数为FormData对象

    @RequestLine("POST /test/upload/single")

    @Headers("Content-Type: multipart/form-data")

    String upload(@Param("file") FormData photo);

    // 上传文件：参数为POJO对象

    @RequestLine("POST /test/upload/single")

    @Headers("Content-Type: multipart/form-data")

    String upload(@Param("file") MyFile myFile);

    class MyFile {

        @FormProperty("is_public")

        Boolean isPublic;

        File file;

        public Boolean getPublic() {

            return isPublic;

        }

        public void setPublic(Boolean aPublic) {

            isPublic = aPublic;

        }

        public File getFile() {

            return file;

        }

        public void setFile(File file) {

            this.file = file;

        }

    }

}

调用接口：

FileAPI fileAPI = Feign.builder()

        .encoder(new FormEncoder()) // 必须明确设置请求参数编码器

        .logger(new Slf4jLogger())

        .logLevel(Logger.Level.FULL)

        .target(FileAPI.class, "http://localhost:8080");

File file1 = new File("C:\\Users\\xxx\\Downloads\\test1.jpg");

File file2 = new File("C:\\Users\\xxx\\Downloads\\test2.jpg");

// 上传文件1：参数为文件对象

fileAPI.upload(file1);

// 上传文件2：参数为字节数组（注意：在服务端无法获取到文件名）

byte[] bytes = FileUtils.readFileToByteArray(file1);

fileAPI.upload(bytes);

// 上传文件3：参数为FormData对象

byte[] bytes = FileUtils.readFileToByteArray(file1);

FormData formData = new FormData("image/jpg", "test1.jpg", bytes);

String result = fileAPI.upload(formData);

// 上传文件4：参数为POJO对象

FileAPI.MyFile myFile = new FileAPI.MyFile();

myFile.setPublic(true);

myFile.setFile(file1);

fileAPI.upload(myFile);

// 上传文件：参数为多个文件

fileAPI.upload(new File[]{file1, file2});

fileAPI.upload(Arrays.asList(new File[]{file1, file2}));

下载文件

定义接口：

public interface FileDownloadAPI {

    // 下载文件

    @RequestLine("GET /test/download/file")

    Response download(@QueryMap Map<String, Object> queryMap);

}

调用接口：

// 下载文件时返回值为Response对象，不需要设置解码器

FileAPI fileAPI = Feign.builder()

                .logger(new Slf4jLogger())

                .logLevel(Logger.Level.FULL)

                .target(FileAPI.class, "http://localhost:8080");

String fileName = "test.jpg";

Map<String, Object> queryMap = new HashMap<>();

queryMap.put("fileName", fileName);

Response response = fileAPI.download(queryMap);

if (response.status() == 200) {

    File downloadFile = new File("D:\\Downloads\\", fileName);

    FileUtils.copyInputStreamToFile(response.body().asInputStream(), downloadFile);

}

使用Spring Cloud Feign

在Spring框架中使用Feign实现文件上传时需要依赖 feign-form 和 feign-form-spring ，这2个模块已经在“Spring Cloud Feign”中自带了，只需要添加 spring-cloud-starter-openfeign 依赖即可。

<!-- 集成Spring和Feign，包含了模块feign-form和feign-form-spring -->

<dependency>

    <groupId>org.springframework.cloud</groupId>

    <artifactId>spring-cloud-starter-openfeign</artifactId>

    <version>3.0.2</version>

</dependency>

<!-- 文件操作工具类 -->

<dependency>

    <groupId>commons-io</groupId>

    <artifactId>commons-io</artifactId>

    <version>2.11.0</version>

</dependency>

上传文件

定义接口及配置：

@FeignClient(value = "FileAPI", url = "http://localhost:8080", configuration = FileUploadAPI.FileUploadAPIConfiguration.class)

public interface FileUploadAPI {

    /**

     * 上传单个文件

     * @param file

     * @return

     */

    @RequestMapping(value = "/test/upload/single", method = RequestMethod.POST, headers = "Content-Type=multipart/form-data")

    String upload(@RequestPart("file") MultipartFile file);

    /**

     * 上传多个文件

     * @param files

     * @return

     */

    @RequestMapping(value = "/test/upload/batch", method = RequestMethod.POST, headers = "Content-Type=multipart/form-data")

    String upload(@RequestPart("files") List<MultipartFile> files);

    class FileUploadAPIConfiguration {

        @Autowired

        private ObjectFactory<HttpMessageConverters> messageConverters;

        @Bean

        public Encoder feignEncoder () {

            return new SpringFormEncoder(new SpringEncoder(messageConverters));

        }

        @Bean

        public Logger feignLogger() {

            return new Slf4jLogger();

        }

        @Bean

        public Logger.Level feignLoggerLevel() {

            return Logger.Level.FULL;

        }

    }

}

调用接口：

// 上传单个文件

File file = new File("C:\\Users\\xxx\\Downloads\\test1.jpg");

FileInputStream fis = new FileInputStream(file);

MockMultipartFile mockMultipartFile = new MockMultipartFile("file", file.getName(), "image/jpg", fis);

this.fileUploadAPI.upload(mockMultipartFile);

fis.close();

// 上传多个文件

File file1 = new File("C:\\Users\\xxx\\Downloads\\test1.jpg");

File file2 = new File("C:\\Users\\xxx\\Downloads\\test2.jpg");

FileInputStream fis1 = new FileInputStream(file1);

FileInputStream fis2 = new FileInputStream(file2);

MockMultipartFile f1 = new MockMultipartFile("files", file1.getName(), "image/jpg", fis1);

MockMultipartFile f2 = new MockMultipartFile("files", file2.getName(), "image/jpg", fis2);

this.fileUploadAPI.upload(Arrays.asList(new MockMultipartFile[]{f1, f2}));

fis1.close();

fis2.close();

下载文件

定义接口：

@FeignClient(value = "FileDownloadAPI", url = "http://localhost:8080", configuration = FileDownloadAPI.FileDownloadAPIConfiguration.class)

public interface FileDownloadAPI {

    /**

     * 下载文件

     * @param fileName 文件名

     * @return

     */

    @RequestMapping(value = "/test/download/file", method = RequestMethod.GET)

    Response download(@RequestParam("fileName") String fileName);

    // 下载文件时返回值为Response对象，不需要设置解码器

    class FileDownloadAPIConfiguration {

        @Bean

        public Logger feignLogger() {

            return new Slf4jLogger();

        }

        @Bean

        public Logger.Level feignLoggerLevel() {

            return Logger.Level.FULL;

        }

    }

}

调用接口：

String fileName = "test.jpg";

Response response = this.fileDownloadAPI.download(fileName);

File destFile = new File("D:\\Downloads\\", fileName);

// 使用org.apache.commons.io.FileUtils工具类将输入流中的内容转存到文件

FileUtils.copyInputStreamToFile(response.body().asInputStream(), destFile);