Java, the number is converted to a string, the string is converted to digital
Step 1: digital-to-string
Method 1: Use the static method valueOf String class
2: first basic types of packing an object, and then calls the object's toString
package digit;
public class TestNumber {
public static void main(String[] args) {
int i = 5;
//方法1
String str = String.valueOf(i);
//方法2
Integer it = i;
String str2 = it.toString();
}
}Step 2: String-to-digital
Static method of Integer parseInt call
package digit;
public class TestNumber {
public static void main(String[] args) {
String str = "999";
int i= Integer.parseInt(str);
System.out.println(i);
}
}Exercise : string conversion
See step
floating point numbers are converted to strings 3.14 "3.14"
then the string "3.14" into a floating point 3.14
If the string is 3.1a4, converting what would get to a float?
The answer :
package digit;
public class TestNumber {
public static void main(String[] args) {
float f = 3.14f;
//浮点数转字符串
String s = String.valueOf(f);
//字符串转浮点数
f= Float.parseFloat(s);
//如果字符串内容不是合法的数字表达，那么转换就会报错(抛出异常)
Float.parseFloat("3.1a4");
}
}