@ConfigurationProperties(prefix = "spring.servlet.multipart", ignoreUnknownFields = false)
public class MultipartProperties {

    /**
     * Whether to enable support of multipart uploads.
     */
    private boolean enabled = true;

    /**
     * Intermediate location of uploaded files.
     */
    private String location;

#######  在这里设置了上传文件的大小#######
    /**
     * Max file size.
     */
    private DataSize maxFileSize = DataSize.ofMegabytes(1);

    /**
     * Max request size.
     */
    private DataSize maxRequestSize = DataSize.ofMegabytes(10);

    /**
     * Threshold after which files are written to disk.
     */
    private DataSize fileSizeThreshold = DataSize.ofBytes(0);

    /**
     * Whether to resolve the multipart request lazily at the time of file or parameter
     * access.
     */
    private boolean resolveLazily = false;

    public boolean getEnabled() {
        return this.enabled;
    }

    public void setEnabled(boolean enabled) {
        this.enabled = enabled;
    }

    public String getLocation() {
        return this.location;
    }

    public void setLocation(String location) {
        this.location = location;
    }

    public DataSize getMaxFileSize() {
        return this.maxFileSize;
    }

    public void setMaxFileSize(DataSize maxFileSize) {
        this.maxFileSize = maxFileSize;
    }

    public DataSize getMaxRequestSize() {
        return this.maxRequestSize;
    }

    public void setMaxRequestSize(DataSize maxRequestSize) {
        this.maxRequestSize = maxRequestSize;
    }

    public DataSize getFileSizeThreshold() {
        return this.fileSizeThreshold;
    }

    public void setFileSizeThreshold(DataSize fileSizeThreshold) {
        this.fileSizeThreshold = fileSizeThreshold;
    }

    public boolean isResolveLazily() {
        return this.resolveLazily;
    }

    public void setResolveLazily(boolean resolveLazily) {
        this.resolveLazily = resolveLazily;
    }

    /**
     * Create a new {@link MultipartConfigElement} using the properties.
     * @return a new {@link MultipartConfigElement} configured using there properties
     */
    public MultipartConfigElement createMultipartConfig() {
        MultipartConfigFactory factory = new MultipartConfigFactory();
        PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
        map.from(this.fileSizeThreshold).to(factory::setFileSizeThreshold);
        map.from(this.location).whenHasText().to(factory::setLocation);
        map.from(this.maxRequestSize).to(factory::setMaxRequestSize);
        map.from(this.maxFileSize).to(factory::setMaxFileSize);
        return factory.createMultipartConfig();
    }

}

    /**
     * Obtain a {@link DataSize} representing the specified number of megabytes.
     * @param megabytes the number of megabytes, positive or negative
     * @return a {@link DataSize}
     */
    public static DataSize ofMegabytes(long megabytes) {
        return new DataSize(Math.multiplyExact(megabytes, BYTES_PER_MB));
    }

import javax.servlet.MultipartConfigElement;
 
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.web.servlet.MultipartConfigFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.util.unit.DataSize;
 
@Configuration
public class TomcatConfig {
 
    @Value("${spring.http.server.maxFileSize}")
    private Long maxFileSize;
    @Value("${spring.http.server.maxRequestSize}")
    private Long maxRequestSize;
 
    @Bean
    public MultipartConfigElement multipartConfigElement() {
        MultipartConfigFactory factory = new MultipartConfigFactory();
        // 单个数据大小
        // factory.setMaxFileSize(MaxFileSize); // KB,MB
        factory.setMaxFileSize(DataSize.ofMegabytes(maxFileSize));
        /// 总上传数据大小
        factory.setMaxRequestSize(DataSize.ofMegabytes(maxRequestSize));
        // factory.setMaxRequestSize(MaxRequestSize);
        return factory.createMultipartConfig();
    }