The Toronto stock market was higher as positive Chinese data lifted commodity prices and mining stocks and the energy sector advanced following Friday’s announcement clarifying takeovers by foreign state-owned energy companies.The S&P/TSX composite index gained 33.42 points to 12,193.01 while the TSX Venture Exchange climbed 0.19 of a point to 1,186.25.The Canadian dollar gained 0.34 of a cent to 101.25 cents US.Markets were, however, weighed down amid the surprise resignation of Italy’s premier, who was widely credited with restoring confidence in Italy as the country deals with a debt crisis and fiscal cliff worries.Prime Minister Mario Monti announced that he intends to resign by the end of the year, saying he found it impossible to lead after former prime minister Silvio Berlusconi’s party, parliament’s largest, dropped its support.The Dow Jones industrials were up 15.32 points to 13,170.45, the Nasdaq gained 5.75 points to 2,983.79 while the S&P 500 index dipped 0.48 of a point to 1,417.59.The federal government on Friday approved two high-profile deals. The state-controlled China National Offshore Oil Corp. (CNOOC) got the green light for its $15.1-billion purchase of Nexen Inc. (TSX:NXY). And Malaysian state-controlled energy company Petronas can go ahead with its $6-billion acquisition of Progress Energy Resources Corp. (TSX:PRQ).Nexen shot up 14.17 per cent to $26.59 while Progress shares jumped 13.4 per cent to $21.96.However, Prime Minister Stephen Harper made it clear that state-owned energy companies will find it extremely difficult to buy up Canadian oilsands producers in future.Shares in some of these companies found themselves the target of sellers since they can no longer realistically hope to be snapped up by foreign state-owned enterprises at fat share price premiums.For example, Meg Energy Corp. (TSX:MEG) was down 86 cents to $33.86 but Athabasca Oil Corp. (TSX:ATH) recovered most of an early loss, down a slight three cents to $10.22.Elsewhere in the energy sector, Spartan Oil Corp. TSX:STO) shares ran ahead 43 cents or nine per cent to $4.83 as it announced it has received an unsolicited takeover offer. No other details on the offer have been released. Spartan is active the Cardium light oil play in central Alberta and the Bakken light oil resource play in southeast Saskatchewan.Precision Drilling Corp. (TSX:PD) plans to cut capital spending to $485 million in 2013 from approximately $920 million this year while also instituting a quarterly dividend of five cents per share. Its shares were up four cents to $7.33.There was also mixed economic data from China, the world’s second-biggest economy. Export growth plunged to 2.9 per cent compared with a year earlier, while imports were flat, down from October’s 2.4 per cent growth.The figures were in line with analysts’ warnings that a trade rebound that began in August was unsustainable due to weak global demand amid Europe’s debt problems and a slow U.S. recovery.At the same time, the Chinese government reported Sunday that factory output increased 10.1 per cent from a year earlier, compared with the previous month’s rise of 9.6 per cent year on year. Retail sales rose 14.9 per cent, up from October’s 14.5 per cent. And electricity consumption rose 7.9 per cent in November from 6.4 per cent in October.Oil prices advanced amid data showing November crude oil shipments to China, the world’s second-biggest oil importer, were just below their all-time high. China imported an average of approximately 5.69 million barrels per day last month, just below February’s record-high 5.98 million barrels per day.The January crude contract on the New York Mercantile Exchange gained 29 cents to US$86.22.The metals and mining sector gained 0.57 per cent while copper prices also advanced sharply with the March contract ahead by five cents to US$3.71 a pound. China is the world’s biggest consumer of the metal, which is viewed as a global economic barometer. HudBay Minerals (TSX:HBM) gained 15 cents to $9.92.The gold sector was up 0.7 per cent while bullion prices also picked up with the February contract up $8.70 to US$1,714.20 an ounce. Iamgold Corp. (TSX:ABX) improved by eight cents to $10.72.Worries about whether the U.S. can head off going over the so-called fiscal cliff at the end of the month continued to cast a shadow over markets.The fiscal cliff is a combination of expiring Bush-era tax cuts and automatic, across-the-board spending cuts due to take effect in January. The worry is that the shock from both measures would cut economic growth significantly and likely push the U.S. back into recession.At the same time, the interest rate on the Italian government’s 10-year bond, an indicator of how risky investors consider a country’s ability to pay down its debt, rose 0.33 percentage points to 4.8 per cent following Monti’s surprise decision to resign.Also adding to investor unease was an announcement from Berlusconi that he was going to run for the premiership.European bourses were mixed with London’s FTSE 100 index up 0.1 per cent, Frankfurt’s DAX added 0.03 per cent and the Paris CAC 40 were off 0.06 per cent.