[Java] double与String之间的相互转换方法

8种基本数据类型有相应的8种包装类(Wrapper)对应,分别是:Character,Byte,Short,Integer,Long,Float,Double,Boolean.

特点:

1.提供了valueOf(String)用于从字符串转换及toString()转换成字符串

2.通过xxxxValue()方法可以得到所包装的值,如Integer对象的intValue()方法.

示例代码:

 

public class DoubleAndString { public static void main(String[] args) { double d; String s; System.out.println("===Change double to String==="); d = 3.1415926;// double d s = "" + d;// this is a interesting convert way System.out.println("s is " + s); s = new Double(d).toString();// toString(String) method System.out.println("s is " + s); s = String.valueOf(d);// valueOf(String) method System.out.println("s is " + s); System.out.println("===change String to double==="); s = "6.12345"; try { d = new Double(s).doubleValue();//xxxValue() method System.out.println("d is " + d); //Returns a new double initialized to the value represented //by the specified String d = Double.parseDouble(s); System.out.println("d is " + d); d = Double.valueOf(s).doubleValue();//doubleValue() method System.out.println("d is " + d); } catch (Exception e) { e.printStackTrace(); } } }