实现从JSON字符串中提取任意属性（包括数组）的Java方法，支持嵌套结构和多种数据类型
import java.util.regex.*;public class HelloWorld {public static void main(String[] args) {// 示例1String json1 = "{\"successflag\": true, \"ddd\":\"true\", \"voucher\":{\"bf\":[{\"cf\":\"1\"}]}}";System.out.println(extractValueByRegex(json1, "billinfo")); System.out.println(extractValueByRegex(json1, "cvoucherflow")); System.out.println(extractValueByRegex(json1, "successflag")); System.out.println(extractValueByRegex(json1, "ddd")); System.out.println(extractValueByRegex(json1, "eeee")); // 输出: [{"cvoucherflow":"1"}] 1 true true null// 示例2String json2 = "{\"billinfo\":[{\"cbillcode\":\"JK_001\"}]}";System.out.println(extractValueByRegex(json2, "billinfo")); // 输出: [{"cbillcode":"JK_001"}]// 示例3String json3 = "{\"returnCode\":[\"0000\",\"0001\"]}";System.out.println(extractValueByRegex(json3, "returnCode")); // 输出: ["0000","0001"]}/*** 提取 JSON 字符串中指定属性的值（支持数组和嵌套）* @param jsonStr JSON 字符串* @param key 要提取的属性名（如 "billinfo"）* @return 属性值的字符串形式，若不存在则返回 null*/public static String extractValueByRegex(String jsonStr, String key) {// 正则匹配：\"key\":\s*(\{[^{}]*\}|\[[^\[\]]*\]|\"[^\"]*\"|true|false|null|\d+\.?\d*)String regex = "\"" + Pattern.quote(key) + "\"\\s*:\\s*(\\{[^{}]*\\}|\\[[^\\[\\]]*\\]|\"[^\"]*\"|true|false|null|\\d+\\.?\\d*)";Pattern pattern = Pattern.compile(regex);Matcher matcher = pattern.matcher(jsonStr);if (matcher.find()) {String matchedValue = matcher.group(1);// 去除字符串值的引号（如果是字符串类型）if (matchedValue.startsWith("\"") && matchedValue.endsWith("\"")) {return matchedValue.substring(1, matchedValue.length() - 1);}return matchedValue; // 直接返回布尔值/数字/null/数组}return null;}
}
