我正在做一个项目，从int到String的所有转换都是这样完成的:
int i = 5;
String strI = "" + i;
我不熟悉Java。
这是惯例吗，还是像我猜想的那样，出了什么问题?
当前回答
String strI = String.valueOf(i);
String string = Integer.toString(i);
两种方法都是正确的。
其他回答
String strI = String.valueOf(i);
String string = Integer.toString(i);
两种方法都是正确的。
尝试简单的类型转换
char c = (char) i;
Mostly ditto on SimonJ. I really dislike the ""+i idiom. If you say String.valueOf(i), Java converts the integer to a string and returns the result. If you say ""+i, Java creates a StringBuilder object, appends an empty string to it, converts the integer to a string, appends this to the StringBuilder, then converts the StringBuilder to a String. That's a lot of extra steps. I suppose if you do it once in a big program, it's no big deal. But if you're doing this all the time, you're making the computer do a bunch of extra work and creating all these extra objects that then have to be cleaned up. I don't want to get fanatic about micro-optimization, but I don't want to be pointlessly wasteful either.
表达式
"" + i
导致I在运行时的字符串转换。表达式的整体类型是String。i首先转换为一个Integer对象(new Integer(i))，然后是String。valueOf(Object obj)被调用。所以它等于
"" + String.valueOf(new Integer(i));
显然，这比直接调用String的性能稍差。valueOf(new Integer(i))，这将产生完全相同的结果。
“”+i的优点是打字更容易/更快，有些人可能会认为，它更容易阅读。这不是一种代码气味，因为它并不表明有任何更深层次的问题。
(参考:JLS 15.8.1)
这取决于你想如何使用你的String。这可以帮助:
String total = Integer.toString(123) + Double.toString(456.789);
