java integer对象判断两个数字是否相等
java integer对象判断两个数字是否相等,不一定对
问题发生的背景:javaweb的项目,起先,因为在java中实体类中的int类型在对象初始化之后会给int类型的数据默认赋值为0,这样在很多地方就会出现不必要的错误,比如没有判断之后就来计算分页,那么就可能出现页码为负数的情况,同时我也看了一片相关的blog,大概意思就是在javaweb中出现的这个问题,尽量不要用int。
好了受了这些影响,我在实体类里很多地方就用了integer类型,前几天都没有发现问题,在昨天做一个数据库相关的操作时,要将两个实体类的某些属性进行比较,(两个实体类中产品的Id)数据也比较巧,id=127 接下来就是id=132,然后在循环中发现127以前的数据比较结果为相等,127以后,从132开始比较时,后面所有的记录都不相等,奇怪了,132明明等于132啊,说到这里有的朋友应该猜到了并且笑了。好吧。还有朋友也会和我第一次遇到这个问题一样不明白啊。好,先看demo
- public void testIntegerAndInt() {
- Integer a = 128;
- Integer b = 128;
- if (a==b)
- {
- System.out.print("Integer Compare Integer : ");
- System.out.println("Y");
- }else
- {
- System.out.print("Integer Compare Integer : ");
- System.out.println("N");
- }
- Integer m = 127;
- Integer n = 127;
- if (m==n)
- {
- System.out.print("int Compare int : ");
- System.out.println(" Y ");
- }
- else
- {
- System.out.print("int Compare int : ");
- System.out.println(" N ");
- }
- }
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" alt="" />
看到了吧,2X2应该由4种组合,但是现在之后2中剩余的来中就不测试了,如果感兴趣可以自己试试
下面在深入的看看为啥
private static class IntegerCache {
static final int low = -128;
static final int high;
static final Integer cache[];
static {
// high value may be configured by property
int h = 127;
String integerCacheHighPropValue =
sun.misc.VM.getSavedProperty("java.lang.Integer.IntegerCache.high");
if (integerCacheHighPropValue != null) {
try {
int i = parseInt(integerCacheHighPropValue);
i = Math.max(i, 127);
// Maximum array size is Integer.MAX_VALUE
h = Math.min(i, Integer.MAX_VALUE - (-low) -1);
} catch( NumberFormatException nfe) {
// If the property cannot be parsed into an int, ignore it.
}
}
high = h;
cache = new Integer[(high - low) + 1];
int j = low;
for(int k = 0; k < cache.length; k++)
cache[k] = new Integer(j++);
// range [-128, 127] must be interned (JLS7 5.1.7)
assert IntegerCache.high >= 127;
}
private IntegerCache() {}
}
大概意思就是-128到127之间不会封装对象而是用常量池的值,不在这个范围才会创建对象。
最后今天无意间发现了一个很有用的blog
http://blog.csdn.net/jackfrued/article/details/44921941
收藏了
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