java类型转换参考大全

来源：互联网发布：centos jdk 环境变量编辑：程序博客网时间：2024/06/15 03:02

integer   to   String   :

         int   i   =   42;
        String   str   =   Integer.toString(i);
        or
        String   str   =   ""   +   i


  double   to   String   :       String   str   =   Double.toString(i);


  long   to   String   :       String   str   =   Long.toString(l);


  float   to   String   :       String   str   =   Float.toString(f);




  String   to   integer   :       str   =   "25";
        int   i   =   Integer.valueOf(str).intValue();
        or
        int   i   =   Integer.parseInt(str);



  String   to   double   :       double   d   =   Double.valueOf(str).doubleValue();



  String   to   long   :       long   l   =   Long.valueOf(str).longValue();
        or
        long   l   =   Long.parseLong(str);



  String   to   float   :       float   f   =   Float.valueOf(str).floatValue();




  decimal   to   binary   :       int   i   =   42;
        String   binstr   =   Integer.toBinaryString(i);




  decimal   to   hexadecimal   :       int   i   =   42;
        String   hexstr   =   Integer.toString(i,   16);
        or
        String   hexstr   =   Integer.toHexString(i);




  hexadecimal   (String)   to   integer   :       int   i   =   Integer.valueOf("B8DA3",   16).intValue();
        or
        int   i   =   Integer.parseInt("B8DA3",   16);





  ASCII   code   to   String       int   i   =   64;
        String   aChar   =   new   Character((char)i).toString();




  integer   to   ASCII   code   (byte)       char   c   =   'A';
        int   i   =   (int)   c;   //   i   will   have   the   value   65   decimal




  To   extract   Ascii   codes   from   a   String           String   test   =   "ABCD";
            for   (   int   i   =   0;   i   <   test.length();   ++i   )   {
                char   c   =   test.charAt(   i   );
                int   i   =   (int)   c;
                System.out.println(i);
                }




  integer   to   boolean       b   =   (i   !=   0);



  boolean   to   integer       i   =   (b)?1:0;



note   :To   catch   illegal   number   conversion,   try   using   the   try/catch   mechanism.   try{
      i   =   Integer.parseInt(aString);
      }
  catch(NumberFormatException   e)
      {
      }