这段代码将一个字符串分离为令牌,并将它们存储在一个字符串数组中,然后将一个变量与第一个home…为什么它不工作?
public static void main(String...aArguments) throws IOException {
String usuario = "Jorman";
String password = "14988611";
String strDatos = "Jorman 14988611";
StringTokenizer tokens = new StringTokenizer(strDatos, " ");
int nDatos = tokens.countTokens();
String[] datos = new String[nDatos];
int i = 0;
while (tokens.hasMoreTokens()) {
String str = tokens.nextToken();
datos[i] = str;
i++;
}
//System.out.println (usuario);
if ((datos[0] == usuario)) {
System.out.println("WORKING");
}
}
equals()函数是Object类的一个方法,程序员需要重写它。String类重写它,以检查两个字符串是否相等,即在内容和不引用。
==运算符检查两个对象的引用是否相同。
考虑程序
String abc = "Awesome" ;
String xyz = abc;
if(abc == xyz)
System.out.println("Refers to same string");
这里的abc和xyz,都是指同一个字符串“Awesome”。因此表达式(abc == xyz)为真。
String abc = "Hello World";
String xyz = "Hello World";
if(abc == xyz)
System.out.println("Refers to same string");
else
System.out.println("Refers to different strings");
if(abc.equals(xyz))
System.out.prinln("Contents of both strings are same");
else
System.out.prinln("Contents of strings are different");
这里abc和xyz是两个具有相同内容“Hello World”的不同字符串。因此,表达式(abc == xyz)为假,而as (abc.equals(xyz))为真。
希望你理解==和<Object>.equals()之间的区别
谢谢。
The == operator checks if the two references point to the same object or not.
.equals() checks for the actual string content (value).
注意.equals()方法属于类Object(所有类的超类)。您需要根据您的类需求重写它,但是对于String,它已经实现,并且它检查两个字符串是否具有相同的值。
Case1)
String s1 = "Stack Overflow";
String s2 = "Stack Overflow";
s1 == s1; // true
s1.equals(s2); // true
Reason: String literals created without null are stored in the string pool in the permgen area of the heap. So both s1 and s2 point to the same object in the pool.
Case2)
String s1 = new String("Stack Overflow");
String s2 = new String("Stack Overflow");
s1 == s2; // false
s1.equals(s2); // true
Reason: If you create a String object using the `new` keyword a separate space is allocated to it on the heap.