How can Java determine if two strings are equal?

There are several ways to check if two strings are equal in Java.

1. Use the equals() method: Call the equals() method of a string object to compare if the contents of two strings are equal.

String str1 = "Hello";
String str2 = "World";

if (str1.equals(str2)) {
    System.out.println("两个字符串相等");
} else {
    System.out.println("两个字符串不相等");
}

1. Use the equalsIgnoreCase() method: Call the equalsIgnoreCase() method of the string object to compare the content of two strings to see if they are equal, ignoring case.

String str1 = "Hello";
String str2 = "hello";

if (str1.equalsIgnoreCase(str2)) {
    System.out.println("两个字符串相等");
} else {
    System.out.println("两个字符串不相等");
}

1. Using the compareTo() method: call the compareTo() method of a string object to compare the sizes of two strings. If the return value is 0, it means the two strings are equal.

String str1 = "Hello";
String str2 = "World";

int result = str1.compareTo(str2);

if (result == 0) {
    System.out.println("两个字符串相等");
} else {
    System.out.println("两个字符串不相等");
}

It is important to note that when using the == operator in Java to compare two string objects, it checks if their memory addresses are equal, not the contents of the strings. Therefore, it is generally not recommended to directly use == to determine if two strings are equal.