Java中常見資料轉型換)

1.int-->short

 exp: short shortvar=0; 


int intvar=0; 


shortvar= (short) intvar

2. short-->int 



exp: short shortvar=0; 


int intvar=0; 


intvar=shortvar;

3. int->String 


exp: int intvar=1; 


String stringvar; 


Stringvar=string.valueOf (intvar);

4. float->String 


exp: float floatvar=9.99f; 


String stringvar; 


Stringvar=String.valueOf (floatvar);

5. double->String 


exp double doublevar=99999999.99; 


String stringvar; 


Stringvar=String.valueOf (doublevar);

6. char->String 


exp char charvar=’a’; 


String stringvar; 


Stringvar=String.valueOf (charvar);

7 String->int、float、long、double 


Exp String intstring=”10”; 


String floatstring=”10.1f”; 


String longstring=”99999999”; 


String doubleString=”99999999.9”;

Int I=Integer.parseInt (intstring); 


Float f= Integer.parseInt (floatstring); 


Long lo=long. parseInt (longstring); 


Double d=double. parseInt (doublestring);

8 String->byte、short 


Exp String s=”0”; 


Byte b=Integer.intValue(s); 


Short sh=Integer.intValue(s);

9 String->char 


Exp String s=”abc”; 


Char a=s.charAt(0); 


返回字元a

10 String-->boolean 


String s=”true”; 


Boolean flag=Boolean.valueOf (“s”);

long-->int,int-->long

這種基本類型強制轉換就可以了

int i = 1;

long l = (long)i;

double d = (double)i;

date(日期)------------>string(字元)

Date d = new Date();

String ss = d.toLocaleString();

or

SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

String ss = format(d);