本篇文章介绍springboot的上传和下载功能。
一、创建springboot工程，添加依赖
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compile("org.springframework.boot:spring-boot-starter-web")
compile("org.springframework.boot:spring-boot-starter-thymeleaf")
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工程目录为：
application.java 启动类
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package hello;
import org.springframework.boot.springapplication;
import org.springframework.boot.autoconfigure.springbootapplication;
import org.springframework.boot.context.properties.enableconfigurationproperties;
@springbootapplication
public class application {
public static void main(string[] args) {
springapplication.run(application.class, args);
}
}
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二、创建测试页面
在resources/templates目录下新建uploadform.html
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<html xmlns:th="http://www.thymeleaf.org">
<body>
<div th:if="${message}">
<h2 th:text="${message}"/>
</div>
<div>
<form method="post" enctype="multipart/form-data" action="/">
<table>
<tr><td>file to upload:</td><td><input type="file" name="file" /></td></tr>
<tr><td></td><td><input type="submit" value="upload" /></td></tr>
</table>
</form>
</div>
<div>
<ul>
<li th:each="file : ${files}">
<a th:href="${file}" rel="external nofollow" th:text="${file}" />
</li>
</ul>
</div>
</body>
</html>
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三、新建storageservice服务
storageservice接口
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package hello.storage;
import org.springframework.core.io.resource;
import org.springframework.web.multipart.multipartfile;
import java.nio.file.path;
import java.util.stream.stream;
public interface storageservice {
void init();
void store(multipartfile file);
stream<path> loadall();
path load(string filename);
resource loadasresource(string filename);
void deleteall();
}
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storageservice实现
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package hello.storage;
import org.springframework.core.io.resource;
import org.springframework.core.io.urlresource;
import org.springframework.stereotype.service;
import org.springframework.util.filesystemutils;
import org.springframework.util.stringutils;
import org.springframework.web.multipart.multipartfile;
import java.io.ioexception;
import java.net.malformedurlexception;
import java.nio.file.files;
import java.nio.file.path;
import java.nio.file.paths;
import java.nio.file.standardcopyoption;
import java.util.function.predicate;
import java.util.stream.stream;
@service
public class filesystemstorageservice implements storageservice
{
private final path rootlocation = paths.get("upload-dir");
/**
* 保存文件
*
* @param file 文件
*/
@override
public void store(multipartfile file)
{
string filename = stringutils.cleanpath(file.getoriginalfilename());
try
{
if (file.isempty())
{
throw new storageexception("failed to store empty file " + filename);
}
if (filename.contains(".."))
{
// this is a security check
throw new storageexception("cannot store file with relative path outside current directory " + filename);
}
files.copy(file.getinputstream(), this.rootlocation.resolve(filename), standardcopyoption.replace_existing);
}
catch (ioexception e)
{
throw new storageexception("failed to store file " + filename, e);
}
}
/**
* 列出upload-dir下面所有文件
* @return
*/
@override
public stream<path> loadall()
{
try
{
return files.walk(this.rootlocation, 1) //path -> !path.equals(this.rootlocation)
.filter(new predicate<path>()
{
@override
public boolean test(path path)
{
return !path.equals(rootlocation);
}
});
}
catch (ioexception e)
{
throw new storageexception("failed to read stored files", e);
}
}
@override
public path load(string filename)
{
return rootlocation.resolve(filename);
}
/**
* 获取文件资源
* @param filename 文件名
* @return resource
*/
@override
public resource loadasresource(string filename)
{
try
{
path file = load(filename);
resource resource = new urlresource(file.touri());
if (resource.exists() || resource.isreadable())
{
return resource;
}
else
{
throw new storagefilenotfoundexception("could not read file: " + filename);
}
}
catch (malformedurlexception e)
{
throw new storagefilenotfoundexception("could not read file: " + filename, e);
}
}
/**
* 删除upload-dir目录所有文件
*/
@override
public void deleteall()
{
filesystemutils.deleterecursively(rootlocation.tofile());
}
/**
* 初始化
*/
@override
public void init()
{
try
{
files.createdirectories(rootlocation);
}
catch (ioexception e)
{
throw new storageexception("could not initialize storage", e);
}
}
}
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storageexception.java
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package hello.storage;
public class storageexception extends runtimeexception {
public storageexception(string message) {
super(message);
}
public storageexception(string message, throwable cause) {
super(message, cause);
}
}
storagefilenotfoundexception.java
package hello.storage;
public class storagefilenotfoundexception extends storageexception {
public storagefilenotfoundexception(string message) {
super(message);
}
public storagefilenotfoundexception(string message, throwable cause) {
super(message, cause);
}
}
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四、controller创建
将上传的文件，放到工程的upload-dir目录，默认在界面上列出可以下载的文件。
listuploadedfiles函数，会列出当前目录下的所有文件
servefile下载文件
handlefileupload上传文件
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package hello;
import java.io.ioexception;
import java.util.stream.collectors;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.core.io.resource;
import org.springframework.http.httpheaders;
import org.springframework.http.responseentity;
import org.springframework.stereotype.controller;
import org.springframework.ui.model;
import org.springframework.web.bind.annotation.exceptionhandler;
import org.springframework.web.bind.annotation.getmapping;
import org.springframework.web.bind.annotation.pathvariable;
import org.springframework.web.bind.annotation.postmapping;
import org.springframework.web.bind.annotation.requestparam;
import org.springframework.web.bind.annotation.responsebody;
import org.springframework.web.multipart.multipartfile;
import org.springframework.web.servlet.mvc.method.annotation.mvcuricomponentsbuilder;
import org.springframework.web.servlet.mvc.support.redirectattributes;
import hello.storage.storagefilenotfoundexception;
import hello.storage.storageservice;
@controller
public class fileuploadcontroller {
private final storageservice storageservice;
@autowired
public fileuploadcontroller(storageservice storageservice) {
this.storageservice = storageservice;
}
@getmapping("/")
public string listuploadedfiles(model model) throws ioexception {
model.addattribute("files", storageservice.loadall().map(
path -> mvcuricomponentsbuilder.frommethodname(fileuploadcontroller.class,
"servefile", path.getfilename().tostring()).build().tostring())
.collect(collectors.tolist()));
return "uploadform";
}
@getmapping("/files/{filename:.+}")
@responsebody
public responseentity<resource> servefile(@pathvariable string filename) {
resource file = storageservice.loadasresource(filename);
return responseentity.ok().header(httpheaders.content_disposition,
"attachment; filename=\"" + file.getfilename() + "\"").body(file);
}
@postmapping("/")
public string handlefileupload(@requestparam("file") multipartfile file,
redirectattributes redirectattributes) {
storageservice.store(file);
redirectattributes.addflashattribute("message",
"you successfully uploaded " + file.getoriginalfilename() + "!");
return "redirect:/";
}
@exceptionhandler(storagefilenotfoundexception.class)
public responseentity<?> handlestoragefilenotfound(storagefilenotfoundexception exc) {
return responseentity.notfound().build();
}
}
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源码下载：https://github.com/hellokittynii/springboot/tree/master/springbootuploadanddownload
总结
以上所述是小编给大家介绍的springboot 文件上传和下载的实现源码，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持！
原文链接：https://blog.csdn.net/u010889616/article/details/79764175