Spring之配置multipartResolver解析器、上传文件、处理文件过程

@Bean
public MultipartResolver multipartResolver(){
    return new StandardServletMultipartResolver();
}

@Override
public void onStartup(ServletContext servletContext) throws ServletException {

    DispatcherServlet dispatcherServlet = new DispatcherServlet();
    ServletRegistration.Dynamic registration = servletContext.addServlet("appServlet", dispatcherServlet);
    registration.addMapping("/");
    registration.setMultipartConfig(new MultipartConfigElement("/tmp/uploads"));
}

@Override
protected void customizeRegistration(ServletRegistration.Dynamic registration) {
    registration.setMultipartConfig(
            new MultipartConfigElement("/tmp/test/uploads")
    );
}

new MultipartConfigElement("/tmp/test/uploads",2097152,4194304,0)

<servlet>
    <servlet-name>appServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
    <multipart-config>
    	<!-- 临时路劲 -->
        <location>/tmp/test/uploads</location>
        <!-- 上传文件的最大值 -->
        <max-file-size>2097152</max-file-size>
        <!--请求的最大容量-->
        <max-request-size>4194304</max-request-size>
    </multipart-config>
</servlet>

@Bean
public MultipartResolver multipartResolver(){
    return new CommonsMultipartResolver();
}

 @Bean
public MultipartResolver multipartResolver() throws IOException {
    CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();
    // 设置 临时目录
    multipartResolver.setUploadTempDir(new FileSystemResource("/tmp/test/uploads"));
    // 最大文件
    multipartResolver.setMaxUploadSize(2097152);
    
    multipartResolver.setMaxInMemorySize(0);
    return multipartResolver;
}

<form action="" method="post" enctype="multipart/form-data">
    <input type="file" name="picture" accept="image/jpeg">
    <input type="submit" value="提交">
</form>

@RequestMapping("/upload")
public String uploadImage(@RequestPart("picture")MultipartFile file) throws IOException {
    // 获取 文件 名
    String filename = file.getOriginalFilename();
    // 将 上传的文件 写入到 文件系统中
    file.transferTo(new File("/data/image"+filename));
    return "index";
}

public interface MultipartFile extends InputStreamSource {
    String getName();

    @Nullable
    String getOriginalFilename();

    @Nullable
    String getContentType();

    boolean isEmpty();

    long getSize();

    byte[] getBytes() throws IOException;

    InputStream getInputStream() throws IOException;

    default Resource getResource() {
        return new MultipartFileResource(this);
    }

    void transferTo(File var1) throws IOException, IllegalStateException;

    default void transferTo(Path dest) throws IOException, IllegalStateException {
        FileCopyUtils.copy(this.getInputStream(), Files.newOutputStream(dest));
    }
}

@RequestMapping("/upload")
public String uploadImage(@RequestPart("picture") Part file) throws IOException {
    // 获取 文件 名
    String filename = file.getSubmittedFileName();
    // 将 上传的文件 写入到 文件系统中
    file.write("/data/image"+filename);
    return "index";
}