java匹配字符串'{'和'}'

闲来无事，看到别人的面试题，随手写写。

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要求："{"与"}"必须同时出现，"{"必须在"}"前面，允许嵌套

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package matcher;import java.util.Stack;public class TestMatcher {public boolean isMatch(String str){if(null==str || "".equals(str)){return false;}Stack stack = new Stack();int i = 0;int len = str.length();while(i<len){char ch = str.charAt(i);if('{'==ch){stack.push(ch);}else if('}'==ch){if(stack.isEmpty()){return false;}stack.pop();}i++;}if(!stack.isEmpty()){return false;}return true;}/** * @param args */public static void main(String[] args) {TestMatcher t = new TestMatcher();System.out.println(t.isMatch("{{}"));System.out.println(t.isMatch("}{"));System.out.println(t.isMatch("{}{}"));System.out.println(t.isMatch("{abc{123{999{}}}}"));}}

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