如何消除嵌套的括号

package java程序员面试笔试宝典;

public class 题8_8_1消除嵌套的括号 {
	public static void main(String[] args) {
		String str="(1,(2,3),(4,(5,6),7))";
		String str1="(1,(2,3),(4,(5,6),7))";
		String str2=null;
		String str3="";
		String str4="()()";
		String str5="((1,(2,3),(4,(5,6),7))";
		boolean flag=strChanger(str5);
		System.out.println(flag);
	}
	public static boolean strChanger(String str){
		if(str==null){
			return false;
		}
		StringBuffer sb=new StringBuffer();
		sb.append('(');
		char[] chs=str.toCharArray();
		int count=0;
		for (int i = 0; i < chs.length; i++) {
			if(chs[i]!='('&&chs[i]!=')'&&chs[i]!=','&&
					!(chs[i]>='0'&&chs[i]<='9')){
				return false;
			}
			if(chs[i]=='('){
				if(i+1