java为表达式字符串设置优先级

Question

我有下面的表达式，我想为Java中的每个条件设置括号“（）”。我想转换下面的表达式

String expression = "((firstname = john AND Lastname = Eleven) OR (salary = 15000 AND location = Mexico OR (firstname = mathew AND lastname = Thirteen)))";

作为

String expression = "(((firstname = john) AND (Lastname = Eleven)) OR ((salary = 15000) AND (location = Mexico) OR ((firstname = mathew) AND (lastname = Thirteen))))";

有没有最好的方法来实现这一点

Answer 1

如果想要实现的是添加括号，那么可以创建一个正则表达式来匹配text[space]=[space]text，然后使用String#replaceAll()方法将其包装在括号中。可以使用以下正则表达式实现匹配：(\w+ = \w+)

String expression = "((firstname = john AND Lastname = Eleven) OR (salary = 15000 AND location = Mexico OR (firstname = mathew AND lastname = Thirteen)))";
String replaceAll = expression.replaceAll("(\\w+ = \\w+)", "($1)");
System.out.println(replaceAll);
//(((firstname = john) AND (Lastname = Eleven)) OR ((salary = 15000) AND (location = Mexico) OR ((firstname = mathew) AND (lastname = Thirteen))))

如果您不需要匹配=符号，而是需要匹配其他运算符，则可以增强正则表达式以包括>、<、>=、<=、!=(\w+ (=|>|<|>=|<=|!=) \w+)或任何其他你想要的