我想为我的 Spring Boot 应用程序添加上传功能; 这是我的上传休息控制器
package org.sid.web;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;
import org.springframework.core.env.Environment;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.FileSystemResource;
import org.sid.entities.FileInfo;
@RestController
public class UploadController {
@Autowired
ServletContext context;
@RequestMapping(value = "/fileupload/file", headers = ("content-type=multipart/*"), method = RequestMethod.POST, consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
public ResponseEntity<FileInfo> upload(@RequestParam("file") MultipartFile inputFile) {
FileInfo fileInfo = new FileInfo();
HttpHeaders headers = new HttpHeaders();
if (!inputFile.isEmpty()) {
try {
String originalFilename = inputFile.getOriginalFilename();
File destinationFile = new File(
context.getRealPath("C:/Users/kamel/workspace/credit_app/uploaded") + File.separator + originalFilename);
inputFile.transferTo(destinationFile);
fileInfo.setFileName(destinationFile.getPath());
fileInfo.setFileSize(inputFile.getSize());
headers.add("File Uploaded Successfully - ", originalFilename);
return new ResponseEntity<FileInfo>(fileInfo, headers, HttpStatus.OK);
} catch (Exception e) {
return new ResponseEntity<FileInfo>(HttpStatus.BAD_REQUEST);
}
} else {
return new ResponseEntity<FileInfo>(HttpStatus.BAD_REQUEST);
}
}
}
但是在邮递员中测试时插入 http://localhost:8082/fileupload/file 并将文件添加到正文中 我收到此错误:“异常”:
org.springframework.web.multipart.support.MissingServletRequestPartException",
"message": "Required request part 'file' is not present
,
这就是您在 Postman 中的请求的样子:
我的示例代码:
application.properties
#max file and request size
spring.http.multipart.max-file-size=10MB
spring.http.multipart.max-request-size=11MB
主要应用类:
Application.java
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
其余控制器类:
import org.springframework.http.MediaType;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
@Controller
@RequestMapping("/fileupload")
public class MyRestController {
@RequestMapping(value = "/file", method = RequestMethod.POST, produces = MediaType.APPLICATION_JSON_VALUE)
public @ResponseBody String myService(@RequestParam("file") MultipartFile file,
@RequestParam("id") String id) throws Exception {
if (!file.isEmpty()) {
//your logic
}
return "some json";
}
}
pom.xml
//...
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
....
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web-services</artifactId>
</dependency>
//...
在你的方法中你已经这样指定了
@RequestParam("file")
。因此它期望密钥是file
。这在异常消息中非常明显。上传文件时,请在 Postman 的 Key
字段中使用此名称。我也遇到了类似的问题,并且收到错误请求部分文件不存在。 但我后来意识到我的应用程序中有这段代码导致了问题:
@Bean(name = "multipartResolver")
public CommonsMultipartResolver multipartResolver() {
CommonsMultipartResolver multipartResolver = new
CommonsMultipartResolver();
multipartResolver.setMaxUploadSize(1000000000);
return multipartResolver;
}
我删除了它,它开始对 RequestPart 和 RequestParam 起作用。 请参阅下面的相关问题:
https://forum.predix.io/questions/22163/multipartfile-parameter-is-not-present-error.html
除了其他发布的答案外,问题可能与处理请求的 servlet 缺少多部分支持有关(对于 Spring 应用程序,是 spring 的 DispatcherServlet)。
可以通过在 web.xml 声明中或初始化期间向调度程序 servlet 添加多部分支持来解决此问题(如果是基于注释的配置)
a) 基于 web-xml 的配置
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>
org.springframework.web.servlet.DispatcherServlet
</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring/dispatcher-config.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
<multipart-config>
<max-file-size>10485760</max-file-size>
<max-request-size>20971520</max-request-size>
<file-size-threshold>5242880</file-size-threshold>
</multipart-config>
</servlet>
</web-app>
b) 对于基于注释的配置,如下所示:
public class AppInitializer implements WebApplicationInitializer {
@Override
public void onStartup(ServletContext servletContext) {
final AnnotationConfigWebApplicationContext appContext = new AnnotationConfigWebApplicationContext();
final ServletRegistration.Dynamic registration = servletContext.addServlet("dispatcher", new DispatcherServlet(appContext));
registration.setLoadOnStartup(1);
registration.addMapping("/");
File uploadDirectory = new File(System.getProperty("java.io.tmpdir"));
MultipartConfigElement multipartConfigElement = new MultipartConfigElement(uploadDirectory.getAbsolutePath(), 100000, 100000 * 2, 100000 / 2);
registration.setMultipartConfig(multipartConfigElement);
} }
然后我们需要提供多部分解析器,它可以解析作为多部分请求发送的文件。对于注释配置,可以通过以下方式完成:
@Configuration
public class MyConfig {
@Bean
public MultipartResolver multipartResolver() {
return new StandardServletMultipartResolver();
}
}
对于基于 xml 的 spring 配置,您需要通过标签声明将此 bean 添加到上下文中:
<bean id="multipartResolver" class="org.springframework.web.multipart.support.StandardServletMultipartResolver" />
除了 Spring 的标准多部分解析器之外,您还可以使用公共实现。然而这种方式需要额外的依赖:
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.3</version>
</dependency>
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="maxUploadSize" value="100000000"/>
</bean>
我遇到了类似的错误问题
Could not resolve parameter [0] in public org.springframework.http.ResponseEntity... Required request part 'file' is not present
,并尝试了很多方法,但一项更改解决了这个问题。
必须更新
// old
@RequestParam("file") MultipartFile inputFile
// new
@RequestParam(value = "file") MultipartFile inputFile
就我而言,我有一个多模块项目;
核心 > API > 管理
Admin 和 api 是核心模块的父级。
核心/图像控制器:
@RequestMapping(value = "/upload/image", method = RequestMethod.POST)
public ResponseEntity uploadBanner(@RequestParam(value = "file", required =
false) MultipartFile bannerFile){...}
管理应用程序初始化器:
@Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
return application.sources(AdminApplicationInitializer.class);
}
@Bean
public MultipartResolver multipartResolver() {
CommonsMultipartResolver resolver = new CommonsMultipartResolver();
//100MB
resolver.setMaxUploadSize(100 * (long) 1024 * 1024);
return resolver;
}
@Bean
public MultipartConfigElement multipartConfigElement() {
MultipartConfigFactory factory = new MultipartConfigFactory();
factory.setMaxFileSize(DataSize.ofMegabytes(200L));
factory.setMaxRequestSize(DataSize.ofMegabytes(200L));
return factory.createMultipartConfig();
}
当我尝试使用核心服务“/upload/image”从api模块上传文件时。 我收到错误:“所需的请求部分‘文件’不存在”。 原因 ApiInitializer 没有像 AdminInitializer 那样配置。
解决方案:我向ApiApplicationInitializer添加了multipartResolver()和multipartConfigElement()方法。然后它就起作用了。
使用
@RequestPart("file")
代替 @RequestParam("file")
。