一、字符串 转 数字
1. 通过 parse 方法
public class StringToFigure {
public static void main(String[] args) {
String s = "12.35";
float y1 = Float.parseFloat(s);
System.out.printf("%f\n", y1);
double y2 = Double.parseDouble(s);
System.out.printf("%f\n", y2);
}
}
2. 通过 valueOf 方法
public class StringToFigure {
public static void main(String[] args) {
String s = "12.35";
float y3 = Float.valueOf(s).floatValue();
System.out.printf("%f\n", y3);
double y4 = Double.valueOf(s).doubleValue();
System.out.printf("%f\n", y4);
}
}
二、数字 转 字符串
1. 通过 toString 方法
public class FigureToString {
public static void main(String[] args){
int i = 1234;
float f = 12.34f;
double d = 123.4;
String s1 = Integer.toString(i);
String s2 = Float.toString(f);
String s3 = Double.toString(d);
System.out.println(s1);
System.out.println(s2);
System.out.println(s3);
}
}
2. 通过 String 类的 valueOf 方法
public class FigureToString {
public static void main(String[] args){
int i = 1234;
float f = 12.34f;
double d = 123.4;
String s4 = String.valueOf(i);
String s5 = String.valueOf(f);
String s6 = String.valueOf(d);
System.out.println(s4);
System.out.println(s5);
System.out.println(s6);
}
}