China says its foreign trade rose 5.1 percent year on year in June, with exports and imports up 4.3 percent and 6.2 percent respectively, official data showed on Tuesday.   According to the General Administration of Customs, the country registered better-than-expected foreign trade performance in the first half of the year.   Foreign trade of goods went down 3.2 percent year on year in the first half to 14.24 trillion yuan (about 2 trillion U.S. dollars), narrowing by 1.7 percentage points compared with the decrease for the first five months.   Following the turbulence in the first quarter, imports and exports of the second quarter showed signs of recovery and stability, and the exports have risen for three consecutive months, said the administration.