The multi-part request contained parameter data (excluding uploaded files) that exceeded

Inapplication.propertiesfile write this:

# Max file size.
spring.http.multipart.max-file-size=1Mb
# Max request size.
spring.http.multipart.max-request-size=10Mb

adjust size according to your need.

Found a solution. Add this code to the same class running SpringApplication.run.

// Set maxPostSize of embedded tomcat server to 10 megabytes (default is 2 MB, not large enough to support file uploads > 1.5 MB)
@Bean
EmbeddedServletContainerCustomizer containerCustomizer() throws Exception {
    return (ConfigurableEmbeddedServletContainer container) -> {
        if (container instanceof TomcatEmbeddedServletContainerFactory) {
            TomcatEmbeddedServletContainerFactory tomcat = (TomcatEmbeddedServletContainerFactory) container;
            tomcat.addConnectorCustomizers(
                (connector) -> {
                    connector.setMaxPostSize(10000000); // 10 MB
                }
            );
        }
    };
}

Edit: Apparently adding this to your application.properties file will also increase the maxPostSize, but I haven't tried it myself so I can't confirm.

multipart.maxFileSize=10Mb # Max file size.
multipart.maxRequestSize=10Mb # Max request size.

There is some difference when we define the properties in the application.properties and application yaml.

In application.yml :

spring:
  http:
    multipart:
      max-file-size: 256KB
      max-request-size: 256KB

And in application.propeties :

spring.http.multipart.max-file-size=128KB spring.http.multipart.max-request-size=128KB

Note : Spring version 4.3 and Spring boot 1.4