The New Jersey Nets traded forward Mickey Johnson and guard Eric (Sleepy) Floyd to the Golden State Warriors last night for guard Michael Ray Richardson.

Richardson, 27, was an NBA All-Star player in 1980, '81 and '82 for the New York Knicks, who drafted him on the first round in 1978. The Knicks traded Richardson to Golden State on Oct. 22 for forward Bernard King. Richardson averaged 33 minutes, 12.7 points, 7.5 assists and was second in the league with 3.16 steals in 32 games for Golden State.

The Nets drafted the all-America Floyd with the 13th selection on the 1982 first round. The 6-foot-3 guard had led Georgetown University in scoring for four years. He matched his career high as a professional just Friday night, 13 points, in the Nets' 120-98 victory over the Chicago Bulls. Floyd started six games and averaged 5.3 points and 11.5 minutes in 43 games. He shot .426 and was the club's best free throw shooter at .844.

The Nets acquired Johnson Nov. 10 from the Milwaukee Bucks in exchange for guard Phil Ford. He will be going to his sixth team in nine seasons. Johnson, 31, was instrumental in New Jersey's 11-game winning streak from Dec. 23 to Jan. 14. He was named NBA player of the week Jan. 3-9. He averaged 23.8 minutes, 13.4 points, 5.3 rebounds, 3.4 assists in 42 games for the Nets but started only seven.

Johnson has admitted that he and New Jersey Coach Larry Brown have "different philosophies . . . Some things (Brown) wants me to do are against the grain of what I'm used to doing." Mainly, he said, he wants to be a regular starter.