java中对象的比较---==与equals的使用注意事项

浏览数：16 / 时间：2015年06月08日

上代码

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    public class JavaTest1
{
    public 
static void main(String[] agrs)
    {
        int 
a=100;
        int 
b=100;
        int 
c=b;
        String str1=new 
String("java");
        String str2=new 
String("java");
        String str3=str2;
         
        if(a==b)
        {
            System.out.println("a==b");
        }
        else
        {
            System.out.println("a!=b");
        }
        if(b==c)
        {
            System.out.println("b==c");
        }
        else
        {
            System.out.println("b!=c");
        }
        if(str1==str2)
        {
            System.out.println("str1==str2");
        }
        else
        {
            System.out.println("str1!=str2");
        }
        if(str2==str3)
        {
            System.out.println("str2==str3");
        }
        else
        {
            System.out.println("str2!=str3");
        }
        if(str1.equals(str2))
        {
            System.out.println("str1 equals str2");
        }
        else
        {
            System.out.println("str1 doesn‘t equal str2");
        }
        if(str2.equals(str3))
        {
            System.out.println("str2 equals str3");
        }
        else
        {
            System.out.println("str2 doesn‘t equal str3");
        }
    }
}