java的各种类型转换全部汇总(推荐)_JAVA教程

java 类型转换 Integer String Long Float Double Date

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.

									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); 

									  } 

									} /* 服务器之家 www.zzvips.com */

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)