Java jLabel.setText（）方法不使用String重载

Question

In a jLabel component, say I have this codes,

JLabel jLabel = new JLabel();
jLabel.setText( 123 ) ;

It generates error. But writing this,

jLabel.setText( 123 + "" ) ;

force to int part to be a string. But I don't think writing int like that way is a good idea! Does this method has any overloaded siblings grasping not a String?

Answer 1

Not much you can do here, setText only takes a String parameter. Alternatively, you could do jLabel.setText(Integer.toString(123)) , if you find this more readable.

As for 123 + "" part, whenever you add some variables and at least one of them is a String , the compiler will automatically call toString on the others and will concatenate all the strings. somevar + "" (empty string) is a quick way of calling somevar.toString() .

Answer 2

The compiler is correct. You are passing a number to a method that wants the string. The reason the second method works is that the jvm is taking the number and the string, and adding them together, which returns a string, which is why it works. Your other option is to do something Integer.toString(123);