简要JAVA数据类型转换

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]); 或
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数据类型转换 ynniebo [收藏]
关键字 类型转换
出处

这是一个例子,说的是JAVA中数据数型的转换.供大家学习引

package cn.com.lwkj.erts.register;
import java.sql.Date;
public class TypeChange {
public TypeChange() {
}
//change the string type to the int type
public static int stringToInt(String intstr)
{
Integer integer;
integer = Integer.valueOf(intstr);
return integer.intValue();
}
//change int type to the string type
public static String intToString(int value)
{
Integer integer = new Integer(value);
return integer.toString();
}
//change the string type to the float type
public static float stringToFloat(String floatstr)
{
Float floatee;
floatee = Float.valueOf(floatstr);
return floatee.floatValue();
}
//change the float type to the string type
public static String floatToString(float value)
{
Float floatee = new Float(value);
return floatee.toString();
}
//change the string type to the sqlDate type
public static java.sql.Date stringToDate(String dateStr)
{
return java.sql.Date.valueOf(dateStr);
}
//change the sqlDate type to the string type
public static String dateToString(java.sql.Date datee)
{
return datee.toString();
}

public static void main(String[] args)
{
java.sql.Date day ;
day = TypeChange.stringToDate("2003-11-3");
String strday = TypeChange.dateToString(day);
System.out.println(strday);
}


}


JAVA中常用数据类型转换函数
虽然都能在JAVA API中找到，整理一下做个备份。

string->byte
Byte static byte parseByte(String s)

byte->string
Byte static String toString(byte b)

char->string
Character static String to String (char c)

string->Short
Short static Short parseShort(String s)

Short->String
Short static String toString(Short s)

String->Integer
Integer static int parseInt(String s)

Integer->String
Integer static String tostring(int i)

String->Long
Long static long parseLong(String s)

Long->String
Long static String toString(Long i)

String->Float
Float static float parseFloat(String s)

Float->String
Float static String toString(float f)

String->Double
Double static double parseDouble(String s)

Double->String
Double static String toString(Double