code: public SqlKit set(Object... columnsValues) {
  		int len = columnsValues.length;
  		if (len % 2 != 0) {
  			throw new IllegalArgumentException("wrong number of arguments for set, columnsValues length can not be odd");
  		}
  		sql.append(SqlKit.set).append(SqlKit.sapce);
  		
  		StringBuilder column = null;
  		for (int index = 0; index < len; index++) {
  			column = new StringBuilder();
  			if (index % 2 == 0) {
  				column.append(columnsValues[index]).append(SqlKit.sapce).append("=");
  			} else {
  				column.append(columnsValues[index]);
  				if (index != len - 1) {
  					column.append(",");
  				}
  			}
  			sql.append(column).append(SqlKit.sapce);
  		}
  		return this;
  	}
docs: set("name","新的值","addr","新的值")
  @param columns
  @return