在本章中,您将学习如何使用Web服务上传和下载文件。
要上传文件,可以使用 MultipartFile 作为请求参数,并且此API应该使用"Multi-Part form "数据值。遵守下面给出的代码-
@RequestMapping(value="/upload", method=RequestMethod.POST, consumes=MediaType.MULTIPART_FORM_DATA_VALUE) public String fileUpload(@RequestParam("file") MultipartFile file) { return null; }
相同的完整代码如下-
package com.learnfk.demo.controller; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import org.springframework.http.MediaType; 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.RestController; import org.springframework.web.multipart.MultipartFile; @RestController public class FileUploadController { @RequestMapping(value="/upload", method=RequestMethod.POST, consumes=MediaType.MULTIPART_FORM_DATA_VALUE) public String fileUpload(@RequestParam("file") MultipartFile file) throws IOException { File convertFile=new File("/var/tmp/"+file.getOriginalFilename()); convertFile.createNewFile(); FileOutputStream fout=new FileOutputStream(convertFile); fout.write(file.getBytes()); fout.close(); return "File is upload successfully"; } }
对于文件下载,应使用InputStreamResource下载文件。需要在Response中设置HttpHeader Content-Disposition 并需要指定应用程序的响应媒体类型。
注意-在以下示例中,文件应在运行应用程序的指定路径上可用。
@RequestMapping(value="/download", method=RequestMethod.GET) public ResponseEntity<Object> downloadFile() throws IOException { String filename="/var/tmp/mysql.png"; File file=new File(filename); InputStreamResource resource=new InputStreamResource(new FileInputStream(file)); HttpHeaders headers=new HttpHeaders(); headers.add("Content-Disposition", String.format("attachment; filename=\"%s\"", file.getName())); headers.add("Cache-Control", "no-cache, no-store, must-revalidate"); headers.add("Pragma", "no-cache"); headers.add("Expires", "0"); ResponseEntity<Object> responseEntity=ResponseEntity.ok().headers(headers).contentLength(file.length()).contentType( MediaType.parseMediaType("application/txt")).body(resource); return responseEntity; }
相同的完整代码如下-
package com.learnfk.demo.controller; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import org.springframework.core.io.InputStreamResource; import org.springframework.http.HttpHeaders; import org.springframework.http.MediaType; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RestController; @RestController public class FileDownloadController { @RequestMapping(value="/download", method=RequestMethod.GET) public ResponseEntity<Object> downloadFile() throws IOException { String filename="/var/tmp/mysql.png"; File file=new File(filename); InputStreamResource resource=new InputStreamResource(new FileInputStream(file)); HttpHeaders headers=new HttpHeaders(); headers.add("Content-Disposition", String.format("attachment; filename=\"%s\"", file.getName())); headers.add("Cache-Control", "no-cache, no-store, must-revalidate"); headers.add("Pragma", "no-cache"); headers.add("Expires", "0"); ResponseEntity<Object> responseEntity=ResponseEntity.ok().headers(headers).contentLength( file.length()).contentType(MediaType.parseMediaType("application/txt")).body(resource); return responseEntity; } }
下面给出了主要的Spring Boot应用程序-
package com.learnfk.demo; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class DemoApplication { public static void main(String[] args) { SpringApplication.run(DemoApplication.class, args); } }
下面给出了Maven构建的代码– 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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.learnfk</groupId> <artifactId>demo</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>demo</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.8.RELEASE</version> <relativePath/> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
下面给出了Gradle Build – build.gradle的代码-
buildscript { ext { springBootVersion='1.5.8.RELEASE' } repositories { mavenCentral() } dependencies { classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}") } } apply plugin: 'java' apply plugin: 'eclipse' apply plugin: 'org.springframework.boot' group='com.learnfk' version='0.0.1-SNAPSHOT' sourceCompatibility=1.8 repositories { mavenCentral() } dependencies { compile('org.springframework.boot:spring-boot-starter-web') testCompile('org.springframework.boot:spring-boot-starter-test') }
现在您可以创建一个可执行的JAR文件,并使用下面给出的Maven或Gradle命令运行Spring Boot应用程序-
对于Maven,请使用以下命令-
mvn clean install
在" BUILD SUCCESS"之后,您可以在目标目录下找到JAR文件。
对于Gradle,您可以使用下面显示的命令-
sgradle clean build
在" BUILD SUCCESSFUL"之后,您可以在build/libs目录下找到JAR文件。
现在,使用以下命令运行JAR文件:
java –jar <JARFILE>
这将在Tomcat端口8080上启动应用程序,如下所示-
现在在POSTMAN应用程序中单击下面的URL,您可以看到如下所示的输出-
文件上传- http:// localhost:8080/upload
文件下载- http:// localhost:8080/upload
祝学习愉快!(内容编辑有误?请选中要编辑内容 -> 右键 -> 修改 -> 提交!)