java equals函数用法详解

2019-11-26 16:16:57

字体：大中小

来源：转载

供稿：网友

equals函数在基类object中已经定义，源码如下

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

从源码中可以看出默认的equals（）方法与“==”是一致的，都是比较的对象的引用，而非对象值（这里与我们常识中equals（）用于对象的比较是相饽的，原因是java中的大多数类都重写了equals（）方法，下面已String类举例，String类equals（）方法源码如下：）
[java]

复制代码代码如下:

 
/** The value is used for character storage. */ 
private final char value[]; 

/** The offset is the first index of the storage that is used. */ 
private final int offset; 

/** The count is the number of characters in the String. */ 
private final int count; 

[java] view plaincopyprint? 
public boolean equals(Object anObject) { 
if (this == anObject) { 
return true; 
} 
if (anObject instanceof String) { 
String anotherString = (String)anObject; 
int n = count; 
if (n == anotherString.count) { 
char v1[] = value; 
char v2[] = anotherString.value; 
int i = offset; 
int j = anotherString.offset; 
while (n-- != 0) { 
if (v1[i++] != v2[j++]) 
return false; 
} 
return true; 
} 
} //www.software8.co 
return false; 
} 