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WebPage obPage1 = new WebPage(null, null, 0); obPage1.setUrl(page1.substring(st + 4, en)); System.out.println(obPage1.toString());这是给我一个空指针异常任何想法在那里我去错了吗?
This is giving me a nullpointer exception any idea where im going wrong?
推荐答案是好康你写了一个自定义类?
Is WebPage a custom class you wrote?
即使你没有实现一个toString方法,它仍然应该返回有效的字符串,因为这将是扩大对象的ToString方法
Even if you didn't implement a toString method, it should still return valid string since it would be extend the Object's toString method
getClass().getName() + '@' + Integer.toHexString(hashCode())
最快捷的方法,以确定哪些code正在做的是运行它的调试器模式,这样你可以什么存储里面的网页。
The quickest way to determine what the code is doing is running it in debugger mode so you can whats being stored inside WebPage.
看起来也像是从您要的toString返回一个页面的URL的例子。如果多数民众赞成的情况下,只是做一个getter方法的URL。
Also looks like from the example that you want toString to return the url of a page. If thats the case, just make a getter for the url.
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尝试打印对象时获得空指针异常
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