What is purpose of MIDI in java if it is not used to play the song

Question

我正在为音乐播放器学习Javasound，但是我对Java中的MIDI和合成器感到困惑，它们之间有什么区别？

Answer 1

MIDI is a control protocol usually used for controlling synthesizers. It was originally devised for different musical hardware to be able to communicated with each other. That is, I can have a control keyboard and a rack of synthesizers from different manufacturers, and I can control that whole rack with my control keyboard. MIDI messages are not sound themselves. A typical MIDI message turns a note on or a note off. It also supports transferring patch data and what not.

The synthesizer is what actually takes all of these commands and produces sound. All the note on/off, control change, patch change, etc.