如果将“字符串数组”转换成“字符串”，只能通过循环，没有其他方法：
public static String getExecSqlString(String str){
StringBuffer sb = new StringBuffer();
String prefixStr = str.substring(0,str.indexOf("("));
String subStr = str.substring(str.indesOf("(")+1,str.substring(")"));
String vals[] = subStr.split("(");
for(int i=0;i<vals.length;i++){
if(i == vals.length-1){
vals[i] = "?";
}else{
if(i == 0){
vals[i] = "(?,";
}else{
vals[i] = "?,";
}
}
sb.append(vals[i]);
}
return prefixStr+sb.toString();
}
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