[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();
}
}
}