Determination is imperative but we have to take into account that:
1. Traditionally China is not a ocean nation. China lacks experience of large scale naval battles. The last naval war we fought, 甲午战争, didn't end well for China.
2. Japan still has the most powerful navy in the region. Their 88 or ten-ten fleets are still formidable at this point and their supporting forces are one of the best in the world.
3. Possible intervention of the US.