不确定你想要的但是：

String str = "alter table $owner.$table_name ENABLE constraint $constraint_name;"
str = str.replace("$owner", "hr")
    .replace("$table_name", "hr")
    .replace("$constraint_name", "scma_constraint");

Javadoc可用此处。

The Javadoc is available here.

replace（）方法返回一个新字符串，该字符串是用newChar替换此字符串中所有出现的oldChar（不支持regexp）

The replace() method returns a new string resulting from replacing all occurrences of oldChar in this string with newChar (without the support of regexp)

replaceAll（）方法执行相同，但在regexp的支持下。

The replaceAll() method does the same, but with the support of regexp.

如果需要，可以更准确地编辑你想要的问题。

If needed, edit your question with more precision on what you want.