在JSP中怎样将数字型变量转为字符型，如何将字符型变量转为数字型，请各位老大指教__String_Integer_int_str_parseInt_

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在JSP中怎样将数字型变量转为字符型，如何将字符型变量转为数字型，请各位老大指教

来源: 互联网发布时间：2015-02-24

本文导语: | 1. Integer to String int i = 42; String str = Integer.toString(i); or String str = "" + i 2. double to String String str = Double.toString(i); 3. long to String String str = Long.toString(l); 4. float to String String str = Float.toStrin...

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

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

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

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

5. String to integer
str = "25";
int i = Integer.valueOf(str).intValue();  or  int i = Integer.parseInt(str);
parseInt(String,int)，这是正确的格式，以前用parseInt(String)是按八进制转换，
所以在使用parseInt("08")时会返回0，正确的使用方法是parseInt("08",10)指明用十进制转换。（在javascript中会发生这种情况，java中不会出现）

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

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

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

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

10. 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);

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

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

13. To extract Ascii codes from a String
String test = "ABCD";
for ( int i = 0; i