Question

给定两个字符串变量s1和s2，(s1 != s2)是否可以为真，而(s1.equals(s2))也是如此？

我会说不，因为如果String s1 = "Hello"; 和String s2 = "hello"; 由于“h”与“H”不相等，但第二部分不可能是真的，因为当作为对象进行比较时它们也不相同。那会有意义吗？

Answer 1

是。只要确保它们是相同的但不是相同的引用（即不实习或通过文字使用字符串池）。这是一个例子：

String s1="teststring";
String s2 = new String("teststring");
System.out.println(s1 != s2); //prints true, different references
System.out.println(s1.equals(s2)); //true as well, identical content.

Answer 2

对于两个字符串，s1和s2，

(s1 != s2)     //Compares the memory location of where the pointers, 
               //s1 and s2, point to

(s1.equals(s2) //compares the contents of the strings

因此，对于s1 = "Hello World"和s2 = "Hello World"：

(s1 == s2) //returns false, these do not point to the same memory location
(s1 != s2) //returns true... because they don't point to the same memory location

(s1.equals(s2)) //returns true, the contents are identical
!(s1.equals(s2)) //returns false

如果是s1 = "Hello World"和s2 = "hello world"，

(s1.equals(s2)) //This returns false because the characters at index 0 
                //and 6 are different

最后，如果你想要一个不区分大小写的比较，你可以这样做：

(s1.toLowerCase().equals(s2.toLowerCase()))  //this will make all the characters 
                                             //in each string lower case before
                                             //comparing them to each other (but
                                             //the values in s1 and s2 aren't 
                                             //actually changed)

Answer 3

String s1 = new String("Hello");
String s2 = new String("Hello");

s1 == s2返回false

s1.equals(s2)返回true

因此，是的，这是可能的，因为默认情况下这些字符串不会在公共池内存中保存/检查，因为不是文字。

分析两个字符串

3 个答案: