简单的正则表达式

一直在想着如何能写出一个正则表达式来判断一个字符串是否为json数组，想来想去没想出办法，先进行第一步，判断其是被{}或[]包裹吧，测试代码如下：

Pattern pattern = Pattern.compile("(^\\[.*\\]$|^\\{.*\\}$){1}");
 String s1 = "[aaa]"; //true
 String s2 = "[aaa";
 String s3 = "aaa]";
 String s4 = "{aaa}";//true
 String s5 = "{aaa";
 String s6 = "aaa}";
 String s7 = "aaa";
 System.out.println(pattern.matcher(s1).matches());
 System.out.println(pattern.matcher(s2).matches());
 System.out.println(pattern.matcher(s3).matches());
 System.out.println(pattern.matcher(s4).matches());
 System.out.println(pattern.matcher(s5).matches());
 System.out.println(pattern.matcher(s6).matches());
 System.out.println(pattern.matcher(s7).matches());

希望尽快找到办法.