[Java] 자바 자주쓰는 형 변환

💚 String 형 → 숫자형

String sNum = "12345";

int i1 = Integer.parseInt(sNum);
int i2 = Integer.valueOf(sNum);

double d = Double.valueOf(sNum);
float f = Float.valueOf(sNum);

long l = Long.parseLong(sNum);
short s = Short.parseShort(sNum);

 

💚 숫자형 → String 형

int i = 1234;
String s1 = String.valueOf(i);
String s2 = Integer.toString(i);

float f = 1.23f;
double d = 1.23;
String s3 = String.valueOf(f);
String s4 = String.valueOf(d);
String s5 = Float.toString(f);
String s6 = Double.toString(d);

long l = 1234;
String s7 = String.valueOf(l);
String s8 = Long.toString(l);

 

💚 String 형 → char형 배열

String s = "813949295024";

char[] arr = s.toCharArray();

for(int i = 0; i < arr.length; i++){
	System.out.println(arr[i]);
}