is there a way to cast any String automatically to its primitive data type in Java? For example having a List with 10 Strings:
string1 = "1234"
string2 = "12.34"
string3 = "String"
string4 = "0.53"
...
I would like to hand them all in a method and get the value back converted in its correct data type (Float, Integer, String):
int1 = 1234
float1 = 12.34
string1 = "String"
float2 = 0.53
...
Simply achieve by RegEx
String string = "/**Place your value*/";
if (string.matches("\\d+")) {
int i = Integer.parseInt(string);
} else if (string.matches("^([+-]?\\d*\\.?\\d*)$)")) {
float f = Float.parseFloat(string);
}
In the same manner you can parse double, long, ....
There is no way to do that. you can test an object for its class by using instanceof
Object integerValue = 1234;
Object doubleValue = 12.34;
Object array = new String[] { "This", "is", "a", "Stringarray" };
if (integerValue instanceof Integer) {
System.out.println("it's an Integer! Classname: " + integerValue.getClass().getName()); // will be printed
}
if (doubleValue instanceof Double) {
System.out.println("this one is a Double *___* Classname: " + doubleValue.getClass().getName()); // will be printed
}
if (array instanceof String) {
System.out.println("Is it a String?");
} else if (array instanceof String[]) {
System.out.println("It's a Stringarray :O! Classname: " + array.getClass().getName()); // will be printed
} else {
System.out.println("Huh? Something went wrong here :D");
}
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.