java中各种类型的相互转换

1 如何将字串 String 转换成整数 int?
A. 有两个方法:
1).int i = Integer.parseInt([String]);

i = Integer.parseInt([String],[int radix]);
2). int i = Integer.valueOf(my_str).intValue();
注: 字串转成 Double, Float, Long 的方法大同小异.

2 如何将整数 int 转换成字串 String ?

A. 有叁种方法:
1.) String s = String.valueOf(i);
2.) String s = Integer.toString(i);
3.) String s = "" + i;
注: Double, Float, Long 转成字串的方法大同小异.

java的各种变量类型的转换

integer to String : int i = 42;
String str = Integer.toString(i);
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();
int i = Integer.parseInt(str);
String to double : double d = Double.valueOf(str).doubleValue();
String to long : long l = Long.valueOf(str).longValue();
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);
String hexstr = Integer.toHexString(i);
hexadecimal (String) to integer :
int i = Integer.valueOf（"B8DA3",16).intValue();
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;
To extract Ascii codes from a Strin 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)
{
}