如何确定String的内容是Integer，Boolean还是Double？

I am currently reading a .properties file in my java project and I noticed every line is read as String (not matter if I use .get() or .getProperty()). So, I was wondering how can I determine, from the contents of a String, if that value is boolean or Integer or double or even a String.

我目前正在我的java项目中读取一个.properties文件，我注意到每一行都被读为String（如果我使用.get（）或.getProperty（），则无关紧要）。所以，我想知道如何根据String的内容确定该值是boolean还是Integer或double或甚至是String。

"asavvvav" --> String
"12345678" --> Integer
"false"    --> Boolean

1 个解决方案

#1

You could use regex:

你可以使用正则表达式：

String booleanRegex = false|true;
String numberRegex = \\d+;

if(input.matches(booleanRegex)) {

} else if(input.matches(numberRegex)) {

} else {
   //is String
}

Or you could attempt to parse and catch the exception:

或者您可以尝试解析并捕获异常：

boolean isNumber = false;
try {
    Integer.parseInt(input);
    isNumber = true;
} catch(NumberFormatException e) {
    e.printStackTrace();
}

To check if it's an enum value:

要检查它是否是枚举值：

try {
    Enum.valueOf(YourEnumType.class, "VALUE");
} catch(IllegalStateException e) {
    e.printStackTrace();
    //was not enum
}

#1