The role of Java string.valueof ()

A cast of data is required to read the data, and a string.valueof (a) can be used to cast a to a string type

Sometimes a is already a string type, but for the rigor of the code, will also add string.valueof (a), then string.valueof (a) omitted will not be wrong.

But sometimes it involves a server problem, so it's better to join String.valueof (a).

Using string.valueof () for data conversion, this method returns a "null" string if the converted data is null

String) method, if the converted data is NULL, a null object is returned instead of a "null" string.

The role of Java string.valueof ()