java中关于String的equals()比较

public class Test2 {

public static void main(String[] args) {
// TODO Auto-generated method stub
String a1 = new String("疯狂Java讲义");
String a2 = new String("疯狂Java讲义");

System.out.println(a1.equals(a2));
System.out.println(a1.hashCode());
System.out.println(System.identityHashCode(a1));
System.out.println(a2.hashCode());
System.out.println(System.identityHashCode(a2));
}

}

true

221331276

110718392

221331276

425918570

String类重写了Object的equals()方法 ：

public boolean equals(Object obj) {
return (this == obj);
}

public boolean equals(Object anObject) {
if (this == anObject) {
return true;
}
if (anObject instanceof String) {
String anotherString = (String)anObject;
int n = value.length;
if (n == anotherString.value.length) {
char v1[] = value;
char v2[] = anotherString.value;
int i = 0;
while (n-- != 0) {
if (v1[i] != v2[i])
return false;
i++;
}
return true;
}
}
return false;
}