在Java 8'+'运算符用于concatinating替换为新的StringBuilder（）[重复](In Java 8 '+' operator for

在Java 8'+'运算符用于concatinating替换为新的StringBuilder（）[重复](In Java 8 '+' operator for concatinating replaced by new StringBuilder() [duplicate]) java

这个问题在这里已有答案：

StringBuilder vs Java中的字符串连接在Java 18答案 中的toString（）

在Java 8中，我编写了一些示例代码。

String s1 = "Hello"; String s2 = "world"; String s3 = s1 + s2;

反编译.class文件后，我发现第3个语句

String s3 = s1 + s2;

取而代之

String s3 = new StringBuilder(s1).append(s2).toString();

这是否意味着不再需要使用显式StringBuilder进行优化而只需使用'+'运算符而不是？

This question already has an answer here:

StringBuilder vs String concatenation in toString() in Java 18 answers

In Java 8, I wrote some sample code.

String s1 = "Hello"; String s2 = "world"; String s3 = s1 + s2;

After decompiling .class file I found that 3rd statement

String s3 = s1 + s2;

replaced by

String s3 = new StringBuilder(s1).append(s2).toString();

Does it mean that There is no longer need to use explicit StringBuilder for Optimization and just use '+' operator instead of?

最满意答案

是。 实际上，这个优化已经在Java 6中完成了。详情请参阅Bruce Eckel的“Thinking in Java”第4版pp.356-359

Yes. Actually, this optimization had been done in Java 6. See Bruce Eckel's "Thinking in Java" 4th edition pp.356-359 for details