[Quote=引用 2 楼 wangqiulei1 的回复:]
我也怀疑过是编译器转化,可是编译器在什么情况下会自动转换的,这种转换是不是有什么条件,如果有条件,条件是什么?麻烦了了
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看《java语言规范》,这是规定
+= 这样的表达式,需要的情况下自动进行强制转换。 http://java.sun.com/docs/books/jls/third_edition/html/expressions.html#15.26.2
15.26.2 Compound Assignment Operators
A compound assignment expression of the form E1 op= E2 is equivalent to E1 = (T)((E1) op (E2)), where T is the type of E1, except that E1 is evaluated only once.
For example, the following code is correct:
short x = 3;
x += 4.6;
and results in x having the value 7 because it is equivalent to: