Java中的NullPointerException问题 | Java中的NullPointerException问题

本文介绍了Java中的NullPointerException问题的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我遇到了NullPointerException问题.

I'm having problems with a NullPointerException.

我正在调试，并且元素不为null，我在第一个IF中有问题，看不到是什么问题.我以为这是在元素的状态为null时发生的，但是我试图对其进行修复，但它不起作用

I was doing the debugging and the element is not null, I have the problem in the first IF and I can not see what the problem is. I thought that happened when the state of the element was null, but I tried to fix it and it did not work

//更新:问题是当我检查状态时

// Update: The problem is when I Check the status

for (Items item : master.getItems()) {
try {
    if (item.getCompany_status().equals("active") || item.getCompany_status().equals("open")) {

if (item.getAddress_snippet() == null) {
    cont2++;
    Company c = new Company(item.getTitle(), "");
    arrayCompany.add(c);
}else {
    cont2++;
    Company c = new Company(item.getTitle(), item.getAddress_snippet());
    arrayCompany.add(c);
}
} catch (Exception e) {
     e.printStackTrace();
}
}
}

推荐答案

我强烈建议采用其他方式使等式:

I strongly recommend to make the equals the other way:

代替:

item.getCompany_status().equals("active")

做:

"active".equals(item.getCompany_status())

通过这种方式，在运行时，如果状态为null，则在它首先检查字符串时不会崩溃.

This way, at runtime, if the status is null, it won't crash as it first checks the string.

"value".equals(null)比null.equals("value")的可能性更大，因为您无法从空对象调用.equals() .

It is more likely to have "value".equals(null) than null.equals("value") as you can't call .equals() from a null object.

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