java String equals,intern
JAVA equals ==
== 2 , equals 2 。
, equals true ,== true;
, ,
, String
public class TestString {
public static void main(String[] args) {
String s1 = "Monday";
String s2 = "Monday";
}
}
?
1. String
, ?
: ,s1 s2
?
String final , 。
, ,
:
public class TestString {
public static void main(String[] args) {
String s1 = "Monday";
String s2 = "Monday";
if (s1 == s2)
System.out.println("s1 == s2");
else
System.out.println("s1 != s2");
}
}
,
, :s1 == s2
!
s1 == s2 ?
== :s1 s2 String -- "Monday"!
2. String
, :
public class TestString {
public static void main(String[] args) {
String s1 = "Monday";
String s2 = new String("Monday");
if (s1 == s2)
System.out.println("s1 == s2");
else
System.out.println("s1 != s2");
if (s1.equals(s2))
System.out.println("s1 equals s2");
else
System.out.println("s1 not equals s2");
}
}
s2 new
:
s1 != s2
s1 equals s2
,
s1 s2 "Monday"String
?
3. String
, :
,
s2 = "Monday" ,
String , ,s1
, s2 , s1
s2 s1 "Monday"
, new , :
“ ! !” "Monday"Sting
。 , ,
。 , , ?
4.
:
public class TestString {
public static void main(String[] args) {
String s1 = "Monday";
String s2 = new String("Monday");
s2 = s2.intern();
if (s1 == s2)
System.out.println("s1 == s2");
else
System.out.println("s1 != s2");
if (s1.equals(s2))
System.out.println("s1 equals s2");
else
System.out.println("s1 not equals s2");
}
}
:s2 = s2.intern();
! :
s1 == s2
s1 equals s2
, s2 , intern()
, s2 s1
5. == equals()
String , String
equals()
String , equals ,
, ,
:
String intern()
new
String s2 = new String("Monday").intern();
, ?
== String
, !
CSDN , :http://blog.csdn.net/ameyume/archive/2010/08/16/5815756.aspx