The first comparison is satisfactory. First, the integer is converted into a string, and then a "0" is added in front of the string. The code is as follows:

int？ num？ =? 10;

String? str？ =? string . value of( 10)；

str？ =? "0"? +? str

Another clever way is to add plastic numbers directly to strings, and java will automatically splice them into strings.

int？ num？ =? 10;

String? str？ =? "0"? +? num