是否应该在生产代码中使用assert语句断言not null？[关闭]

Question

class CustomObject {
    private Object object;

    @Nullable
    public Object getObject() {
        return (object == null) ? generateObject() : object;
    }
}

现在想象一下我是这样使用的：

public void useObject(CustomObject customObject) {
    object = customObject.getObject();
    assert object != null;
    // Do stuff using object, which would throw a NPE if object is null.
}

我被告知我应该删除断言，它们永远不能用于生产代码，只能用于测试。那是真的吗？

Answer 1

为此使用objects.requirenonnull(Object)。

检查指定的对象引用是否为空。此方法主要用于在方法和构造函数中进行参数验证，[...]

在您的情况下，这将是：

java prettyprint-override">public void useObject(CustomObject customObject) {
    object = customObject.getObject();
    Objects.requireNonNull(object); // throws NPE if object is null
    // do stuff with object
}

Foo foo = Objects.requireNonNull(service.fetchFoo());

// you cannot write it in one line.
Bar bar = service.fetchBar();
assert bar != null;

service.foo(Objects.requireNonNull(service.getBar()));

// you cannot write it in one line.
Bar bar = service.getBar();
assert bar != null;
service.foo(bar);