使用REST服务上载和下载文件

转x33g5p2x  于2022-10-15 转载在 其他  
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本rest服务教程是使用rest服务处理文件上传和下载的快速指南。我们将通过rest服务示例演示如何使用具有不同前端（AngularJS和JSP）的JAX-RS API上传和下载文件。最重要的是，我们将展示如何构建JUnit测试来测试使用RESTEasy客户端API上传的文件。

使用REST服务上载和下载文件

为了管理文件上载和下载，我们将使用核心JAX-RS API和Rest Easy实现，以及Apache Commons IO库中的IOUtil类。以下是我们Rest端点的源代码：

  1. package com.mastertheboss.rest;
  3. import java.io.File;
  4. import java.io.FileOutputStream;
  5. import java.io.IOException;
  6. import java.io.InputStream;
  7. import java.util.ArrayList;
  8. import java.util.List;
  9. import java.util.Map;
  10. import javax.annotation.PostConstruct;
  11. import javax.servlet.ServletContext;
  12. import javax.ws.rs.*;
  13. import javax.ws.rs.core.*;
  14. import javax.ws.rs.core.Response.ResponseBuilder;
  16. import org.apache.commons.io.IOUtils;
  17. import org.jboss.resteasy.plugins.providers.multipart.InputPart;
  18. import org.jboss.resteasy.plugins.providers.multipart.MultipartFormDataInput;
  20. @Path("/file")
  21. public class RestFilesDemo {
  23. 	@Context
  24. 	private ServletContext context;
  26. 	@POST
  27. 	@Path("/upload")
  28. 	@Consumes(MediaType.MULTIPART_FORM_DATA)
  29. 	public Response uploadFile(MultipartFormDataInput input) throws IOException {
  31. 		Map<String, List<InputPart>> uploadForm = input.getFormDataMap();
  33. 		// Get file data to save
  34. 		List<InputPart> inputParts = uploadForm.get("attachment");
  36. 		for (InputPart inputPart : inputParts) {
  37. 			try {
  39. 				MultivaluedMap<String, String> header = inputPart.getHeaders();
  40. 				String fileName = getFileName(header);
  42. 				// convert the uploaded file to inputstream
  43. 				InputStream inputStream = inputPart.getBody(InputStream.class, null);
  45. 				byte[] bytes = IOUtils.toByteArray(inputStream);
  47. 				//String path = System.getProperty("user.home") + File.separator + "uploads";
  48. 				File customDir = new File(Config.UPLOAD_FOLDER);
  50. 				if (!customDir.exists()) {
  51. 					customDir.mkdir();
  52. 				}
  53. 				fileName = customDir.getCanonicalPath() + File.separator + fileName;
  54. 				writeFile(bytes, fileName);
  56. 				return Response.status(200).entity("Uploaded file name : " + fileName+" . <br/> <a href='"+context.getContextPath()+"'>Back</a>").build();
  58. 			} catch (Exception e) {
  59. 				e.printStackTrace();
  60. 			}
  61. 		}
  62. 		return null;
  63. 	}
  65. 	@POST
  66. 	@Path("/download")
  67. 	@Produces(MediaType.APPLICATION_OCTET_STREAM)
  68. 	@Consumes("application/x-www-form-urlencoded")
  69. 	public Response downloadFileWithPost(@FormParam("file") String file) {
  71. 		String path = System.getProperty("user.home") + File.separator + "uploads";
  72. 		File fileDownload = new File(path + File.separator + file);
  73. 		ResponseBuilder response = Response.ok((Object) fileDownload);
  74. 		response.header("Content-Disposition", "attachment;filename=" + file);
  75. 		return response.build();
  76. 	}
  78. 	@GET
  79. 	@Path("/download")
  80. 	@Produces(MediaType.APPLICATION_OCTET_STREAM)
  81. 	public Response downloadFileWithGet(@QueryParam("file") String file) {
  82. 		System.out.println("Download file "+file);
  83. 		File fileDownload = new File(Config.UPLOAD_FOLDER + File.separator + file);
  84. 		ResponseBuilder response = Response.ok((Object) fileDownload);
  85. 		response.header("Content-Disposition", "attachment;filename=" + file);
  86. 		return response.build();
  87. 	}
  89. 	@GET
  90. 	@Path("/list")
  91. 	@Produces(MediaType.APPLICATION_JSON)
  92. 	public List<String> listFiles() {
  94. 		List<String> listFiles = new ArrayList<>();
  95. 		File fileFolder = new File(Config.UPLOAD_FOLDER);
  96. 		File[] list = fileFolder.listFiles();
  98. 		for (File f: list) {
  99. 			if (!f.isDirectory()) {
  100. 				listFiles.add(f.getName());
  101. 			}
  102. 		}
  103. 		return listFiles;
  104. 	}
  106. 	private String getFileName(MultivaluedMap<String, String> header) {
  108. 		String[] contentDisposition = header.getFirst("Content-Disposition").split(";");
  110. 		for (String filename : contentDisposition) {
  111. 			if ((filename.trim().startsWith("filename"))) {
  112. 				String[] name = filename.split("=");
  113. 				String finalFileName = name[1].trim().replaceAll("\"", "");
  114. 				return finalFileName;
  115. 			}
  116. 		}
  117. 		return "unknown";
  118. 	}
  119. 	// Utility method
  120. 	private void writeFile(byte[] content, String filename) throws IOException {
  121. 		File file = new File(filename);
  123. 		if (!file.exists()) {
  124. 			file.createNewFile();
  125. 		}
  126. 		FileOutputStream fop = new FileOutputStream(file);
  127. 		fop.write(content);
  128. 		fop.flush();
  129. 		fop.close();
  130. 	}
  131. }

以下是所用方法的一些详细信息：

*listFiles：此方法返回Config.UPLOAD_FOLDER中可用的文件列表
*uploadFile（MultipartFormDataInput输入）：此方法上载File，使用HTTP POST方法中的MULTIPART_FORM_DATA
*downloadFileWithPost（@FormParam（“file”）String文件）：此方法从HTTP POST下载文件，生成二进制流，并将文件名作为Form参数传递
*downloadFileWithGet（@QueryParam（“file”）String file）：此方法还下载file，但它包含filename作为Query参数

接下来，为了确保“uploads”文件夹存在，以下Context Listener将在部署应用程序后创建该文件夹：

  1. package com.mastertheboss.rest;
  3. import javax.servlet.ServletContextEvent;
  4. import javax.servlet.ServletContextListener;
  5. import javax.servlet.annotation.WebListener;
  6. import java.io.File;
  8. @WebListener
  9. public class WebContextListener implements ServletContextListener {
  10.     @Override
  11.     public void contextInitialized(ServletContextEvent sce) {
  12.         if (!new File(Config.UPLOAD_FOLDER).exists()) {
  13.             new File(Config.UPLOAD_FOLDER).mkdir();
  14.         }
  16.     }
  17.     @Override
  18.     public void contextDestroyed(ServletContextEvent sce) {
  19.         //. . .
  20.     }
  21. }

为Rest Service示例的前端编码

有几种方法可以休息我们的rest上传服务。这里我们将展示一个REST客户端集合，它可以将文件作为多部分表单数据发送。

使用Postman上载文件

如果您正在使用Postman测试您的REST服务，您所需要做的就是创建一个New|HTTP请求t。
从HTTP请求用户界面：
1.输入REST服务的URL（例如。http://localhost:8080/rest-文件管理器/resr/file/upload）
1.选择POST作为方法
1.在Body中选择表单数据
1.输入类型文件的键“附件”。上载“值”列中的文件
例如：


小时
最后，单击发送从Postman上传文件。

使用AngularJS上载文件

首先，创建以下索引。使用AngularJS控制器与我们的REST服务交互的jsp页面：

  1. <html>
  2. <head>
  3.  <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.min.js"></script>
  4.  <link rel="stylesheet" type="text/css" href="stylesheet.css" media="screen" />
  6. <script type = "text/javascript">
  7. 	angular.module('app', [])
  8. 	.controller('ctrl', function ($scope, $http) {
  9. 		$scope.files = [];
  11. 		$scope.loadData = function () {
  12. 			$http({
  13. 				method: 'GET',
  14. 				url: '/rest-file-manager/rest/file/list'
  15. 			}).then(function successCallback(response) {
  16. 				$scope.files = response.data;
  17. 			}, function errorCallback(response) {
  18. 				console.log(response.statusText);
  19. 			});
  20. 		}
  22. 		$scope.downloadFile = function (filename) {
  24. 			$http({
  25. 				method: 'GET',
  26. 				url: '/rest-file-manager/rest/file/download',
  27. 				params: {
  28. 					file: filename
  29. 				},
  30. 				responseType: 'arraybuffer'
  32. 			}).success(function (data, status, headers) {
  34. 				headers = headers();
  36. 				var contentType = headers['content-type'];
  37. 				var linkElement = document.createElement('a');
  39. 				try {
  41. 					var blob = new Blob([data], {
  42. 						type: contentType
  43. 					});
  45. 					var url = window.URL.createObjectURL(blob);
  47. 					linkElement.setAttribute('href', url);
  48. 					linkElement.setAttribute("download", filename);
  50. 					var clickEvent = new MouseEvent("click", {
  52. 						"view": window,
  53. 						"bubbles": true,
  54. 						"cancelable": false
  56. 					});
  58. 					linkElement.dispatchEvent(clickEvent);
  60. 				} catch (ex) {
  61. 					console.log(ex);
  62. 				}
  64. 			}).error(function (data) {
  65. 				console.log(data);
  66. 			});
  68. 		};
  70. 		//call loadData when controller initialized
  71. 		$scope.loadData();
  72. 	})
  73. </script>
  75. <title>REST Download demo with AngularJS</title>
  76. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  77. </head>
  78. <body ng-app='app' ng-controller='ctrl'>
  79.     <h1>REST Upload/Download demo using AngularJS</h2>
  80. 	<h2>Upload file</h2>
  81. 	<form method="post" action="rest/file/upload"
  82. 		enctype="multipart/form-data">
  83. 		<input type="hidden" name="action" value="upload" /> <label>Load
  84. 			your file:</label> <input type="file" name="attachment" /> <br /> <input
  85. 			type="submit" value="Upload file" />
  86. 	</form>
  88. 	<h2>Download file</h2>
  90.         <div class="divTable blueTable">
  91.                 <div class="divTableHeading">
  92.                     <div  class="divTableHead">File Name</div>
  93.                     <div  class="divTableHead">Action</div>
  94.                 </div>
  95.                 <div class="divTableRow" ng-repeat="file in files">
  96.                     <div class="divTableCell">{{ file }}</div>
  97.                     <div class="divTableCell"><a ng-click="downloadFile( file )" class="myButton">Download</a> </div>
  98.                 </div>
  99.             </div>
  100. </body>
  101. </html>

接下来，使用以下方法部署示例应用程序：

  1. mvn clean install wildfly:deploy

最后，下面是我们在上传示例XML文件后Rest Endpoint的工作方式：


小时

一个简单的JSP/HTML文件管理器

为了上传和下载文件，您还可以使用一种最简单的方法：一个包含JSP代码的HTML页面。JSP部分主要用于显示服务器上可用的文件列表：

  1. <%@page import="java.io.*, com.mastertheboss.rest.Config" %>
  2.         <%@page import="java.util.*" %> 
  3.         <%!        public void GetDirectory(String a_Path, Vector a_files, Vector a_folders) {
  4.                 File l_Directory = new File(a_Path);
  5.                 File[] l_files = l_Directory.listFiles();
  7.                 for (int c = 0; c < l_files.length; c++) {
  8.                     if (l_files[c].isDirectory()) {
  9.                         a_folders.add(l_files[c].getName());
  10.                     } else {
  11.                         a_files.add(l_files[c].getName());
  12.                     }
  13.                 }
  16.             }
  17.         %> 
  20. <html>
  21. <head>
  22. <title>Start Page</title>
  23. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  24. </head>
  25. <body>
  26. 	<h2>REST Upload demo</h2>
  27. 	<form method="post" action="rest/file/upload"
  28. 		enctype="multipart/form-data">
  29. 		<input type="hidden" name="action" value="upload" /> <label>Load
  30. 			your file:</label> <input type="file" name="attachment" /> <br /> <input
  31. 			type="submit" value="Upload file" />
  32. 	</form>
  34. 	<h2>REST Download demo</h2>
  35. 	<form method="POST" action="rest/file/download">
  36. 		File name: <input type="text" name="file"> 
  37. 		<input type="submit">
  40. 	</form>
  41. 	
  42. 	<h2>Current Directory $HOME/uploads:</h2>
  43. 	<br/>
  44. 	        <%
  45.             Vector l_Files = new Vector(), l_Folders = new Vector();
  46.             GetDirectory(Config.UPLOAD_FOLDER, l_Files, l_Folders);
  47.             out.println("<ul>");   
  48.             for (int a = 0; a < l_Files.size(); a++) {
  49.                 out.println("<li>" + l_Files.elementAt(a).toString() + "</li>");
  50.             }
  51.             out.println("</ul>");
  52.            
  53.         %> 
  54. </body>
  55. </html>

下面是我们正在使用的简单JSP前端：


小时

添加JUnit Test类以测试REST上载

最后，我们在本教程中包括一个JUnit Test类示例，它显示了其中最难的部分：使用REST Easy Client API管理多部件请求以上载文件：

  1. package com.mastertheboss.test;
  3. import static org.junit.Assert.assertEquals;
  4. import static org.junit.Assert.assertTrue;
  6. import java.io.File;
  7. import java.io.FileInputStream;
  8. import java.io.FileNotFoundException;
  9. import java.io.PrintWriter;
  10. import java.io.UnsupportedEncodingException;
  12. import javax.ws.rs.client.Client;
  13. import javax.ws.rs.client.ClientBuilder;
  14. import javax.ws.rs.client.Entity;
  15. import javax.ws.rs.client.WebTarget;
  16. import javax.ws.rs.core.GenericEntity;
  17. import javax.ws.rs.core.MediaType;
  18. import javax.ws.rs.core.Response;
  20. import org.jboss.resteasy.plugins.providers.multipart.MultipartFormDataOutput;
  21. import org.junit.Test;
  23. public class TestRest {
  25.     String FILENAME="test-file.txt";
  26.     @Test
  27.     public void sendFile() throws Exception {
  28.          
  29.         Client client = ClientBuilder.newClient();
  31.     	WebTarget target = client.target("http://localhost:8080/rest-file-manager/rest/file/upload");
  32.     	
  33.     	MultipartFormDataOutput mdo = new MultipartFormDataOutput();
  35.     	createFile();
  37.     	File filePath = new File(FILENAME);
  38.     	
  39.     	// Check that file exists
  41.     	assertTrue(filePath.exists());
  42.     	
  43.     	mdo.addFormData("attachment", new FileInputStream(filePath),
  44.     		    MediaType.APPLICATION_OCTET_STREAM_TYPE,filePath.getName());
  45.     	
  46.     	GenericEntity<MultipartFormDataOutput> entity = new GenericEntity<MultipartFormDataOutput>(mdo) {};
  47.     	
  48.     	Response r = target.request().post( Entity.entity(entity, MediaType.MULTIPART_FORM_DATA_TYPE));
  49.     	
  50.     	// Check that upload was successful
  51.     	assertEquals(r.getStatus(), 200);
  52.     	
  53.     	 
  54. }
  56.     private void createFile() {
  57.         try {
  58.             PrintWriter writer = new PrintWriter(FILENAME, "UTF-8");
  59.             writer.println("Some text");
  60.             writer.close();
  61.         } catch (FileNotFoundException e) {
  62.             e.printStackTrace();
  63.         } catch (UnsupportedEncodingException e) {
  64.             e.printStackTrace();
  65.         }
  66.     }
  68. }

型
这是pom。用于构建和部署项目的xml文件：

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <project xmlns="http://maven.apache.org/POM/4.0.0"
  3. 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  4. 	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  5. 	<modelVersion>4.0.0</modelVersion>
  7. 	<groupId>com.mastertheboss</groupId>
  8. 	<artifactId>rest-file-manager</artifactId>
  9. 	<version>1.1</version>
  10. 	<packaging>war</packaging>
  12. 	<name>rest-file-manager</name>
  14. 	<properties>
  15. 		<endorsed.dir>${project.build.directory}/endorsed</endorsed.dir>
  16. 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  17. 		<version.server.bom>19.0.0.Final</version.server.bom>
  19. 	</properties>
  21. 	<dependencyManagement>
  22. 		<dependencies>
  23. 			<dependency>
  24. 				<groupId>org.wildfly.bom</groupId>
  25. 				<artifactId>wildfly-jakartaee8-with-tools</artifactId>
  26. 				<version>${version.server.bom}</version>
  27. 				<type>pom</type>
  28. 				<scope>import</scope>
  29. 			</dependency>
  30. 		</dependencies>
  31. 	</dependencyManagement>
  33. 	<dependencies>
  35. 		<dependency>
  36. 			<groupId>org.jboss.spec.javax.servlet</groupId>
  37. 			<artifactId>jboss-servlet-api_4.0_spec</artifactId>
  38. 			<scope>provided</scope>
  39. 		</dependency>
  41. 		<dependency>
  42. 			<groupId>commons-io</groupId>
  43. 			<artifactId>commons-io</artifactId>
  44. 			<version>2.6</version>
  45. 		</dependency>
  47. 		<dependency>
  48. 			<groupId>commons-logging</groupId>
  49. 			<artifactId>commons-logging</artifactId>
  50. 			<version>1.2</version>
  51. 		</dependency>
  53. 		<dependency>
  54. 			<groupId>org.jboss.resteasy</groupId>
  55. 			<artifactId>resteasy-jaxrs</artifactId>
  56. 			<scope>provided</scope>
  57. 		</dependency>
  59. 		<dependency>
  60. 			<groupId>org.jboss.resteasy</groupId>
  61. 			<artifactId>resteasy-multipart-provider</artifactId>
  62. 			<scope>provided</scope>
  63. 		</dependency>
  65. 		<dependency>
  66. 			<groupId>org.jboss.spec.javax.ws.rs</groupId>
  67. 			<artifactId>jboss-jaxrs-api_2.1_spec</artifactId>
  68. 			<scope>provided</scope>
  69. 		</dependency>
  72. 		<dependency>
  73. 			<groupId>org.jboss.resteasy</groupId>
  74. 			<artifactId>resteasy-client</artifactId>
  75. 			<scope>test</scope>
  76. 		</dependency>
  78. 		<dependency>
  79. 			<groupId>junit</groupId>
  80. 			<artifactId>junit</artifactId>
  81. 			<scope>test</scope>
  82. 		</dependency>
  83. 	</dependencies>
  85. 	<build>
  87. 		<finalName>rest-file-manager</finalName>
  88. 		<plugins>
  89. 			<plugin>
  90. 				<groupId>org.wildfly.plugins</groupId>
  91. 				<artifactId>wildfly-maven-plugin</artifactId>
  92. 				<version>2.0.0.Final</version>
  93. 				<configuration>
  94. 					<filename>${project.build.finalName}.war</filename>
  95. 				</configuration>
  96. 			</plugin>
  97. 			<plugin>
  98. 				<groupId>org.apache.maven.plugins</groupId>
  99. 				<artifactId>maven-compiler-plugin</artifactId>
  100. 				<version>3.1</version>
  101. 				<configuration>
  102. 					<source>1.8</source>
  103. 					<target>1.8</target>
  104. 					<compilerArguments>
  105. 						<endorseddirs>${endorsed.dir}</endorseddirs>
  106. 					</compilerArguments>
  107. 				</configuration>
  108. 			</plugin>
  109. 			<plugin>
  110. 				<groupId>org.apache.maven.plugins</groupId>
  111. 				<artifactId>maven-war-plugin</artifactId>
  112. 				<version>2.3</version>
  113. 				<configuration>
  114. 					<failOnMissingWebXml>false</failOnMissingWebXml>
  115. 				</configuration>
  116. 			</plugin>
  117. 			<plugin>
  118. 				<groupId>org.apache.maven.plugins</groupId>
  119. 				<artifactId>maven-dependency-plugin</artifactId>
  120. 				<version>2.6</version>
  121. 				<executions>
  122. 					<execution>
  123. 						<phase>validate</phase>
  124. 						<goals>
  125. 							<goal>copy</goal>
  126. 						</goals>
  127. 						<configuration>
  128. 							<outputDirectory>${endorsed.dir}</outputDirectory>
  129. 							<silent>true</silent>
  130. 							<artifactItems>
  131. 								<artifactItem>
  132. 									<groupId>javax</groupId>
  133. 									<artifactId>javaee-endorsed-api</artifactId>
  134. 									<version>7.0</version>
  135. 									<type>jar</type>
  136. 								</artifactItem>
  137. 							</artifactItems>
  138. 						</configuration>
  139. 					</execution>
  140. 				</executions>
  141. 			</plugin>
  142. 			<plugin>
  143. 				<groupId>org.apache.maven.plugins</groupId>
  144. 				<artifactId>maven-surefire-plugin</artifactId>
  145. 			</plugin>
  146. 		</plugins>
  148. 	</build>
  149. 	<profiles>
  150. 		<profile>
  151. 			<id>install</id>
  152. 			<activation>
  153. 				<activeByDefault>true</activeByDefault>
  154. 			</activation>
  155. 			<properties>
  156. 				<maven.test.skip>true</maven.test.skip>
  157. 			</properties>
  158. 		</profile>
  159. 		<profile>
  160. 			<id>test</id>
  161. 			<properties>
  162. 				<maven.test.skip>false</maven.test.skip>
  163. 			</properties>
  164. 		</profile>
  165. 	</profiles>
  166. </project>

要运行测试，请使用“测试”配置文件，如下所示：

  1. $ mvn -Ptest test

测试Rest Service示例cURL

最后，我们将提到，您还可以使用cURL测试文件上载：

  1. $ curl -F file=@"/tmp/file.txt" http://localhost:8080/rest-file-manager/rest/file/upload
  2. Successfully uploaded - file.txt

本Rest服务教程的源代码

您可以在这里找到这个rest服务教程的源代码：https://github.com/fmarchioni/mastertheboss/tree/master/javaee/rest-file-manager。

版权说明 : 本文为转载文章, 版权归原作者所有 版权申明

原文链接 : http://www.mastertheboss.com/jboss-frameworks/resteasy/using-rest-services-to-manage-download-and-upload-of-files/

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