1如何將字串?String?轉換成整數?int??

A.?有兩個方法:?

1).?int?i?=?Integer.parseInt([String]);?或?
i?=?Integer.parseInt([String],[int?radix]);?

2).?int?i?=?Integer.valueOf(my_str).intValue();?

注:?字串轉成?Double,?Float,?Long?的方法大同小異.?

2?如何將整數?int?轉換成字串?String???

A.?有叁種方法:?

1.)?String?s?=?String.valueOf(i);?

2.)?String?s?=?Integer.toString(i);?

3.)?String?s?=?""?+?i;?

注:?Double,?Float,?Long?轉成字串的方法大同小異.?

?

JAVA數據類型轉換?ynniebo?[收藏]?
關鍵字?類型轉換?
出處?

這是一個例子,說的是JAVA中數據數型的轉換.供大家學習引?

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中常用數據類型轉換函數?
雖然都能在JAVA?API中找到，整理一下做個備份。?

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)?

（?附?基本數據類型的大小）
?基本型別???大小??????最小值?????????最大值?
?boolean???-----?????-----??????????------?
?char??????16-bit????Unicode?0??????Unicode?2^16-1?
?byte??????8-bit?????-128???????????+127?
?short?????16-bit????-2^15??????????+2^15-1?
?int???????32-bit????-2^31??????????+2^31-1?
?long??????64-bit????-2^63??????????+2^63-1?
?float?????32-bit????IEEE754????????IEEE754?
?double????64-bit????IEEE754????????IEEE754?
?void???

注意！：表格里的^代表的是次方哈～?