2014/03/13 关于“= =”；“compareTo”；“equals”的区别

关于对“= =”；“compareTo”；“equals”；三者的对比

“= =” 主要是两个变量值的比较,返回值为true 或者是false；

"equals()" 主要是用来比较两个对象(引用)是否相同

“compareTo”该方法用于判断一个字符串是大于、等于还是小于另一个字符串，判断字符串大小的依据是根据它们在字典中的顺序决定的，若二者相等则返回值等于0，若前者大于后者则返回值大于0。

public class Duibi {

public static void main(String[] args) {

Character a = new Character('a');

Character b = new Character('a');

Character h = new Character('c');

Boolean x = a.compareTo(b)==0;

Boolean g = h.compareTo(b)>0;

Boolean z = a.equals(b);

Boolean v = (a==b);

System.out.print("x值为"+x+" "+"g值为"+g+" "+"z值为"+z+" "+"v值为"+v+" "+"\n");

System.out.print("\\\\\\\\\\\\"+"\n");

String na1 = "nihao";

String na2 = new String("nihao");

int num1 = 35;

int num2 = 35;

Boolean e = (na1==na2);
//na1和na2在内存中的地址是不一样的，所以返回的值是一个false

Boolean q = (num1==num2);

Boolean f = na1.equals(na2);

System.out.print(e+" "+q+" "+f);

System.out.print("\n"+"\\\\\\\\\\\\"+"\n");

String an= "Niagara. O roar again!";

char aChar = an.charAt(9); // 输出指定位置的字符

System.out.print(aChar);

｝

｝

运行结果为：

x值为true g值为true z值为true v值为false

\\\\\\

false true true

\\\\\\

O