使用Feign扩展包怎么实现微服务间文件上传
使用Feign扩展包怎么实现微服务间文件上传?相信很多没有经验的人对此束手无策,为此本文总结了问题出现的原因和解决方法,通过这篇文章希望你能解决这个问题。
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单文件上传
2.1 feign_upload_first服务提供者
文件上传的服务提供者接口比较简单,如下所示:
@SpringBootApplication public class FeignUploadFirstApplication { @RestController public class UploadController { @RequestMapping(value = "/uploadFile",method = RequestMethod.POST, consumes = MediaType.MULTIPART_FORM_DATA_VALUE) public String handleFileUpload(@RequestPart(value = "file") MultipartFile file) { return file.getOriginalFilename(); } } public static void main(String[] args) { SpringApplication.run(FeignUploadFirstApplication.class, args); } }
2.2 feign_upload_second服务消费者
增加扩展包依赖
io.github.openfeign.form feign-form 3.3.0 io.github.openfeign.form feign-form-spring 3.3.0 commons-fileupload commons-fileupload 1.3.3
新增feign实现文件上传的配置类
@Configuration public class FeignSupportConfig { @Bean public Encoder feignFormEncoder() { return new SpringFormEncoder(); } }
feign远程调用接口
@FeignClient(name = "file",url = "http://localhost:8100",configuration = FeignSupportConfig.class) public interface UploadService { @RequestMapping(value = "/uploadFile", consumes = MediaType.MULTIPART_FORM_DATA_VALUE) String handleFileUpload(@RequestPart(value = "file") MultipartFile file); }
上传文件接口
@RestController public class UploadController { @Autowired UploadService uploadService; @RequestMapping(value = "/uploadFile",method = RequestMethod.POST, consumes = MediaType.MULTIPART_FORM_DATA_VALUE) public String handleFileUpload(@RequestPart(value = "file") MultipartFile file) { return uploadService.handleFileUpload(file); } }
2.3 测试
使用postman进行测试,可以正常上传文件
三、多文件上传
既然单个文件可以上传,那么多文件应该也没问题吧,我们对上面的代码进行修改
3.1 feign_upload_first服务提供者
文件上传的服务提供者接口比较简单,如下所示:
@SpringBootApplication public class FeignUploadFirstApplication { @RestController public class UploadController { @RequestMapping(value = "/uploadFile",method = RequestMethod.POST, consumes = MediaType.MULTIPART_FORM_DATA_VALUE) public String handleFileUpload(@RequestPart(value = "file") MultipartFile file) { return file.getOriginalFilename(); } @RequestMapping(value = "/uploadFile2",method = RequestMethod.POST, consumes = MediaType.MULTIPART_FORM_DATA_VALUE) public String handleFileUpload(@RequestPart(value = "file") MultipartFile[] file) { String fileName = ""; for(MultipartFile f : file){ fileName += f.getOriginalFilename()+"---"; } return fileName; } } public static void main(String[] args) { SpringApplication.run(FeignUploadFirstApplication.class, args); } }
3.2 feign_upload_second服务消费者
feign远程调用接口
@FeignClient(name = "file",url = "http://localhost:8100",configuration = FeignSupportConfig.class) public interface UploadService { @RequestMapping(value = "/uploadFile", consumes = MediaType.MULTIPART_FORM_DATA_VALUE) String handleFileUpload(@RequestPart(value = "file") MultipartFile file); @RequestMapping(value = "/uploadFile2", consumes = MediaType.MULTIPART_FORM_DATA_VALUE) String handleFileUpload(@RequestPart(value = "file") MultipartFile[] file); }
上传文件接口
@RestController public class UploadController { @Autowired UploadService uploadService; @RequestMapping(value = "/uploadFile",method = RequestMethod.POST, consumes = MediaType.MULTIPART_FORM_DATA_VALUE) public String handleFileUpload(@RequestPart(value = "file") MultipartFile file) { return uploadService.handleFileUpload(file); } @RequestMapping(value = "/uploadFile2",method = RequestMethod.POST, consumes = MediaType.MULTIPART_FORM_DATA_VALUE) public String handleFileUpload2(@RequestPart(value = "file") MultipartFile[] file) { return uploadService.handleFileUpload(file); } }
3.3 测试
经过测试发现,无法上传多个文件。经过检查,发现源码里底层是有对MultipartFile[]类型的支持的,源码中有个类叫SpringManyMultipartFilesWriter,是专门针对文件数组类型进行操作的,但是配置到项目里的SpringFormEncoder类里却没有对文件数组类型的判断,以致不能支持文件数组的上传
SpringManyMultipartFilesWriter源码
public class SpringManyMultipartFilesWriter extends AbstractWriter { private final SpringSingleMultipartFileWriter fileWriter = new SpringSingleMultipartFileWriter(); public SpringManyMultipartFilesWriter() { } public void write(Output output, String boundary, String key, Object value) throws Exception { if (value instanceof MultipartFile[]) { MultipartFile[] files = (MultipartFile[])((MultipartFile[])value); MultipartFile[] var6 = files; int var7 = files.length; for(int var8 = 0; var8 < var7; ++var8) { MultipartFile file = var6[var8]; this.fileWriter.write(output, boundary, key, file); } } else if (value instanceof Iterable) { Iterable> iterable = (Iterable)value; Iterator var11 = iterable.iterator(); while(var11.hasNext()) { Object file = var11.next(); this.fileWriter.write(output, boundary, key, file); } } } public boolean isApplicable(Object value) { if (value == null) { return false; } else if (value instanceof MultipartFile[]) { return true; } else { if (value instanceof Iterable) { Iterable> iterable = (Iterable)value; Iterator> iterator = iterable.iterator(); if (iterator.hasNext() && iterator.next() instanceof MultipartFile) { return true; } } return false; } } }
SpringFormEncoder源码
public class SpringFormEncoder extends FormEncoder { public SpringFormEncoder() { this(new Default()); } public SpringFormEncoder(Encoder delegate) { super(delegate); MultipartFormContentProcessor processor = (MultipartFormContentProcessor)this.getContentProcessor(ContentType.MULTIPART); processor.addWriter(new SpringSingleMultipartFileWriter()); processor.addWriter(new SpringManyMultipartFilesWriter()); } public void encode(Object object, Type bodyType, RequestTemplate template) throws EncodeException { if (!bodyType.equals(MultipartFile.class)) { super.encode(object, bodyType, template); } else { MultipartFile file = (MultipartFile)object; Mapdata = Collections.singletonMap(file.getName(), object); super.encode(data, MAP_STRING_WILDCARD, template); } } }
从上面SpringFormEncoder的源码上可以看到SpringFormEncoder类构造时把SpringManyMultipartFilesWriter实例添加到了处理器列表里了,但是在encode方法里又只判断了MultipartFile类型,没有判断数组类型,底层有对数组的支持但上层却缺少了相应判断。那么我们可以自己去扩展FormEncoder,仿照SpringFormEncoder源码,只修改encode方法。
3.3 扩展FormEncoder支持多文件上传
扩展FormEncoder,命名为FeignSpringFormEncoder
public class FeignSpringFormEncoder extends FormEncoder { /** * Constructor with the default Feign's encoder as a delegate. */ public FeignSpringFormEncoder() { this(new Default()); } /** * Constructor with specified delegate encoder. * * @param delegate delegate encoder, if this encoder couldn't encode object. */ public FeignSpringFormEncoder(Encoder delegate) { super(delegate); MultipartFormContentProcessor processor = (MultipartFormContentProcessor) getContentProcessor(ContentType.MULTIPART); processor.addWriter(new SpringSingleMultipartFileWriter()); processor.addWriter(new SpringManyMultipartFilesWriter()); } @Override public void encode(Object object, Type bodyType, RequestTemplate template) throws EncodeException { if (bodyType.equals(MultipartFile.class)) { MultipartFile file = (MultipartFile) object; Map data = Collections.singletonMap(file.getName(), object); super.encode(data, MAP_STRING_WILDCARD, template); return; } else if (bodyType.equals(MultipartFile[].class)) { MultipartFile[] file = (MultipartFile[]) object; if(file != null) { Map data = Collections.singletonMap(file.length == 0 ? "" : file[0].getName(), object); super.encode(data, MAP_STRING_WILDCARD, template); return; } } super.encode(object, bodyType, template); } }
注册配置类
@Configuration public class FeignSupportConfig { @Bean public Encoder feignFormEncoder() { return new FeignSpringFormEncoder(); } }
看完上述内容,你们掌握使用Feign扩展包怎么实现微服务间文件上传的方法了吗?如果还想学到更多技能或想了解更多相关内容,欢迎关注创新互联行业资讯频道,感谢各位的阅读!
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