与StringBuilder不一致在循环中追加

Question

我在循环中使用StringBuilder时出现问题，因为输出不一致。请帮忙！！！

String oldStr = "job1.job2.job3";
String[] newStr = oldStr.split(Pattern.quote("."));
StringBuilder result = new StringBuilder();
for (String temp : newStr) {    
    String key = "This is "+keyStr+" ,";
    result.append(key);
    System.out.println(key.toString());
}

我希望结果是

This is job1.  
This is job1.  This is job2.
This is job1.  This is job2.  This is job3.

我确实在某个时刻看到了预期的结果，但我现在看到了这些：

This is job1.  
This is job2.  
This is job3.

如果我继续运行代码，我会看到多个元素：

This is job1.  
This is job2.  
This is job3.
This is job1.  
This is job2.  
This is job3.

我的代码是否存在问题，或者StringBuilder的行为不正确？ TIA。

Answer 1

更改此行

System.out.println(key.toString());

到

System.out.println(result.toString());