jdbc sql批量更新

public int updateArticleInfoFalg(List<ArticleInfo> list,String flag){
		
		int count=0;
		ArticleInfo obj = null;
		PreparedStatement pt = null;
		Connection conn = null;
		String sql="update search set flag=? where id=?";
		try{
			conn = DBConnection.getConnection();
			pt = conn.prepareStatement(sql);//不能放在for里面，否则会报空指针异常
			for(int i=0;i<list.size();i++){
				
				obj = (ArticleInfo) list.get(i);
				

				pt.setString(1,flag);
				pt.setInt(2, obj.getId());
				
				pt.addBatch();
				if(i%100==0){
					pt.executeBatch();
				}
				count++;
			}
			pt.executeBatch();
		}catch(Exception ex){
			ex.printStackTrace();
			count=-1;
		}
		return count;
	}