java - 字符串连接，然后在循环中附加

Question

找到了 Bruce Eckel 所著的《Thinking in Java》一书的摘录。

If you try to take shortcuts and do something like append(a + ": " + c) , the compiler will jump in and start making more StringBuilder objects again.

这是否意味着我们不应该用一行代码替换一组追加操作？例如 result.append(i + ": "+ 2*i + "")？

StringBuilder result = new StringBuilder();
for(int i = 0; i < 25; i++) {
    result.append(i);
    result.append(": ");
    result.append(2*i);
    result.append(", ") 
}

上述说法也适用于 Java 8 吗？

摘自此answer关于SO:(让我更加困惑)

At the point where you're concatenating in a loop - that's usually when the compiler can't substitute StringBuilder by itself.

也欢迎与首选编码风格相关的任何方面。

Answer 1

编译器不会有效地为您进行优化。从风格上来说，我会这样写。

StringBuilder result = new StringBuilder();
for (int i = 0; i < 25; i++) {
    result.append(i).append(": ").append(2 * i).append(", ");
}

注意:IDE(例如 IntelliJ)将检测并为此提供自动修复，因为它是常见的翻译。