equals和==

java378656992

/*
* 对于基本数据类型,要用==进行比较,它比较数值数否相等就行了
* 对象用==比较的意思是:比较对象的引用是否相等,或者说两个引用是否指向同一对象.
* equals方法:表示对象的值是否相等(具体指向的值).
*
* */
package mytest;
class AClass{
int cint = 1;
}
public class Compare1 {
String s1 = new String("abc");
String s2 = new String("abc");
int i1=1;
int i2=1;
public static void main(String[] args){
Compare1 c=new Compare1();
AClass c1 = new AClass();
AClass c2 = new AClass();
System.out.println("i1==i2?"+(c.i1==c.i2));
System.out.println("s1.equals(s2)?"+(c.s1.equals(c.s2)));
System.out.println("s1==s2?"+(c.s1==c.s2));
c.s1=c.s2;
System.out.println("s1.equals(s2)afters1=s2"+(c.s1.equals(c.s2)));
System.out.println("s1==s2 after s1=s2?"+(c.s1==c.s2));
System.out.println("c1==c2?"+(c1==c2));
System.out.println("c1.equals(c2)?"+(c1.equals(c2)));
c1=c2;
System.out.println("c1==c2 after c1=c2?"+(c1==c2));
System.out.println("c1.equals(c2) after c1=c2?"+(c1.equals(c2)));

}
}