编写一个APPLICATION遇到一个奇怪的问题

String op1=new String(op);

		System.out.println("op1 len="+op1.length());

        op1=asciiToString(op1);

        System.out.println("op1="+op1);

asciiToString() 方法的作用就是把ASCII码转化成字符。op的内容为10210011510611710310011712111510311712110310211712110011510210011510611710310011712111510311712110310211712110011510210011510611710310011712111510311712110310211712110011510210011510611710310011712111510311712110310211712110011510210011510611710310011712111510311712110310211712110011510210011510611710310011712111510311712110310211712110011510210011510611710310011712111510311712110310211712110011510210011510611710310011712111510311712110310211712110011510210115106117103100117121115103117121103102117121100115102100115106117103100117121115103117121103102117121100115
转化之后乱码。
但是，我要是把代码换成

String op1="把上面一大串数字填进去";

		System.out.println("op1 len="+op1.length());

        op1=asciiToString(op1);

        System.out.println("op1="+op1);

转化之后就完全正确。
不知道是什么原因，请众大神们解答解答
java ascii string 乱码 application --------------------编程问答-------------------- 你传过来的op，能保证是正确格式的“把上面一大串数字填进去”不？在String op1=new String(op);之前，打印下op，看看是不是调用者传递的op有问题。 --------------------编程问答-------------------- 你不把asciiToString的内容打出来怎么搞 --------------------编程问答--------------------
String op1="把上面一大串数字填进去";
        System.out.println("op1 len="+op1.length());
        op1=asciiToString(op1);
        System.out.println("op1="+op1);
请问你这是asciiToString还是string to ascii?

补充：Java ,  Java SE