http {
    # ...
    client_max_body_size 20M; # 设置最大允许大小为 20MB
    # ...
}

tomcat 413 Request Entity Too Large

<Connector port="8080" protocol="HTTP/1.1"
           connectionTimeout="20000"
           redirectPort="8443"
           maxPostSize="104857600" /> <!-- 设置为100MB -->